Isolation and Antimicrobial Sensitvity pattern of Salmonella species, Staphylococcus aureus and Escherichia coli from diarrheic dairy calves in selected dairy Farms of Mekelle and Wukro, Tigray, Northern Ethiopia.

Isolation and Antimicrobial Sensitvity pattern of Salmonella species, Staphylococcus aureus and Escherichia coli from diarrheic dairy calves in selected dairy Farms of Mekelle and Wukro, Tigray, Northern Ethiopia. | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Isolation and Antimicrobial Sensitvity pattern of Salmonella species, Staphylococcus aureus and Escherichia coli from diarrheic dairy calves in selected dairy Farms of Mekelle and Wukro, Tigray, Northern Ethiopia. Melesew Adisu, Girmay Hiluf, Abrhet Alem This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8512251/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A cross-sectional study was carried out from October, 2024 to February, 2025 in Mekelle and Wukro districts with the objective of isolation and determination of the antimicrobial susceptibility profile of Salmonella species, Staphylococcus aureus and Escherichia coli isolated from clinically diarrheic dairy calves. A total of 50 faecal samples were collected directly from the rectum of diarrheic calves and brought to the Microbiology laboratory of Mekelle University, College of Veterinary Medicine, for bacteriological examination. Isolation and identification of the microorganisms were done on the basis of their colony and cellular morphology, staining, and primary and secondary biochemical tests targeted for each pathogen. Furthermore, the antimicrobial susceptibility profile of the isolated bacteria were carried out using disc diffusion method. Only 38 of the total 50 faecal samples, yield Salmonella species, Staphylococcus aureus and Escherichia coli. Out of the total 38 fecal samples, 19 (50%) samples were positive for E. coli , 12 (31.6%) samples were positive for Salmonella species and 7 (18.4%) samples were positive for Staphylococcus aureus. The antibiogram study revealed that most of E.coli , Salmonella species and Staphylococcus aureus isolates were sensitive to Streptomycin, Polymyxin-B and Gentamycin. However, most of E.coli , Salmonella species and Staphylococcus aureus isolates were resistant to Clindamycin, Kanamycin and Methicillin. Most Staphylococcus aureus isolates were susceptible to penicillin, erthromycin and clindamycin whereas resistant was developed against penicillin, erthromycin and clindamycin by most isolates of E.coli and Salmonella species. In conclusion, E.coli and Salmonella were the bacterial species frequently isolated from diarrheic dairy calves in the study area. The results of this study indicated that the isolates were susceptible to limited antimicrobial agents. Most isolates were found susceptible to Streptomycin, Polymyxin-B and Gentamycin. Further characterization and potential effect of the isolated bacteria on the health and productivity of the calf needs to be studied further. General Microbiology Antibiotic susceptibility diarrheic dairy calf Escherichia coli Mekelle Salmonella species Staphylococcus aureus Wukro Figures Figure 1 Figure 2 1. INTRODUCTION Ethiopia has very large livestock populations with diverse genetic makeup inhabiting diverse agro-ecological zones (Aiello and May, 1998). Estimates for farmer holding in rural areas indicate that the country has about 50.9 million heads of cattle, 22 million goats, 26.0 million sheep and 2.3 million camels (CSA, 2010/11). In Ethiopia, livestock plays multiple economic and social roles. On the basis of statistics acquired from different sources, livestock sector offers about 16% of the total GDP that is equivalent to 40% of total agricultural GDP excluding the values of draught power, transport and manure and contributes to the livelihoods of about 60–70% of the Ethiopian population and generates 14% of the country’s foreign exchange earnings (CSA, 2009; Halderman, 2004). In Sub Sahran Africa livestock plays a curcial role in economic development of the countries and living standared of rural communities by serving as source of income and food. Export of live animals and animal products make substainal contribution to the foriegn exchange earnigs of many countries (ILCA, 1998). As in many other countries, livestocke play multiple roles in Ethiopia being a major natural source of feed, industrial raw materials, export earnings and form an integral part of the agriculture production system. However, thier productivity is low due to various constriants such as disease, poor nutrition, poor managment practies and low reproductive performance of the indigenous breeds (DACA, 2006; Lobago, 2006). Livestock is an intergral parts of the agricultural production system in most countries and plays an important role in national economy as well as in socio-economic development of millions of rural household (Radostits et al. , 2000). Dairy farming is a growing livestock production system in Ethiopia (Abdisa and Minda, 2016). Because of better availability of milk market in urban and peri-urban areas, dairy farms are concentrated in these areas of the country. A successful dairy farm operation requires that a large percentage of cows wean a live healthy calf every year. Rearing healthy dairy calves to weaning time requires maximizing the calf’s level of immunity against disease while minimizing its exposure to infectious agents. However, among the factors that have been hindering success of dairy industry, morbidity and mortality of calves is the one that causes major concern (Asefa et al ., 2016). Neonatal calf diarrhea is one of the most common diseases in young animals, causing huge economic and productivity losses to bovine industry worldwide (Cho and Yoon, 2014). Diarrhoea in farm animals, especialy in neonatal calves is one of the most challenging clinical syndromes encountered by many practicing veterinary practitionners. Diarrhoea is a leading cause of economic losses to the cattle industry and major cause of calf mortality and morbidity during first few weeks of life in most countries (Radostits et al ., 2000). Calf diarrhea is a multifactorial disease entity that can have serious financial and animal welfare implications in both dairy and beef herds. It has been estimated that 75% of early calf mortality in dairy herds is caused by acute diarrhea in the pre-weaning period (Sunday et al. , 2016). Diarrhea is a well-known clinical sign in neonatal animals with complex etiology. Managemental, environmental, nutritional, physiological variations and variety of pathogens including bacteria, viruses, protozoa and intestinal parasites are described as important agents causing diarrhea in these animals (Elham et al ., 2012). Enteropathogens have been recognized as major causes of diarrhea in calves. Enterotoxigenic E. coli (ETEC) and Salmonella are known to be the most common and economically important bacterial agents (SJ Achá etselected et al. , 2004). However, other bacteria, including Campylobacter, Staphylococcus and Clostridium spp. have also been identified as the cause of enteric disease and diarrhea in calves (Prescott et al. , 2008). In acute neonatal diarrhea, an important disease of calves, four micro-organisms in particular, are of widespread occurrence and proven entero-pathogenicity: rotavirus, coronavirus, cryptosporidium and enterotoxigenic E. coli (Elham et al ., 2016). The economic losses due to calf mortality and morbidity occur not only from mortality but also from treatment costs, subsequent chronic ill hrift and impaired growth performance (Bazeley, 2003). Overfeeding, overpopulation cold temperature bad hygienne, artificial feeding and colostrums deprivation are all predisposing factors which can be important in the complex etiology of the disease (Debnath et al ., 1987). Currently, the other major concern to animal and human health is the issue of antimicrobial resistance due to indiscriminate use of antibiotics in livestock production as well as human diseases conditions in developing countries. In Ethiopia, the major antibiotics used for treatment of animal and human diseases include Penicillin, Streptomycin, Gentamycin and Oxytetracycline. The indiscriminate use of these antibiotics leads to antibiotic resistance. Several fragmented studies conducted in different sectors magnify the problem of antibiotic resistance. Most therapeutic attempts are based on the tentative diagnosis of the disease and do not have rational basis to select effective antibiotics. Knowledge of the diversity and antibiotic sensitivity profiles of the etiologic agents is necessary for effective control of calf diarrhea. Hence, this study was carried out with the following objectives. To isolate and identify Salmonella species, Staphylococcus aureus and Escherichia coli from diarrheic dairy calves in Mekelle and Wukro districts. To determine the antimicrobial susceptibility patterns of the isolated bacteria against selected antibiotic discs. 2. MATERIALS AND METHODS 2.1. Study Area The study was conducted from October, 2024 to February, 2025 in urban and periurban dairy farrms of Mekelle and Wukro districts, Tigray region, Northern Ethiopia. Mekelle is the capital city of Tigray regional state which is geographically located at 39 0 29’E and 13 0 30’N, and 783Km far from Addis Ababa. It is also located at an altitude of 2000 m.a.s.l. The mean annual rain fall of the study area is 628.8mm and rain is associated with the North and South oscillation of the inter-tropical conversion zone. The annual minimum and maximum temperature is 11.8 0 C and 29.9 0 C, respectively (BANRO, 1998). Wukro is one of the 47 weredas in Tigray situated in the Eastern Zone 45 kms far away north of Mekelle. The town is found at 2140-2250m above sea levels with a climate of Weina Degua. The total size of the town is 860 hectares, with comfortable environment for residential, has an average temperature of 19.730 c and annual average rainfall of 690.25mm (OFED, 2008). Source (ArcGIS, 2012). 2.2. Study Animals The study animals were cross breed dairy calves which are under twelve months old of both sexes, managed under differnt farming system located in Mekelle and Wukro districts. First the study animals were selected purposively and divided according to their location as urban (Mekelle and Wukro town) and peri-urban (the surrounding area within Mekelle and Wukro town). Fecal samples were collected from calves selected based on the diarrheic clinical signs. 2.2.1. Case definition Diarrheic Calves are those with diarrhea and exhibiting signs of systemic disease such as increased rectal temperature, poor appetite, dehydration, decreased mentation, and reduced suckle reflex and had pasty–watery feces with different colors. 2.3. Study Design A cross-sectional study was carried out from October, 2018 to February, 2019 to isolate and determine the antimicrobial susceptibility profile of Salmonella species, Staphylococcus aureus and Escherichia coli from feces of clinically diarrheic calves in Mekelle and Wukro districts. 2.4. Sample Size Determination and Sampling Technique The dairy farms were purposively selected based on the accessibility and availability of diarheic calves. All calves fulfilling the inclusion criteria were considered for sampling. The sample size was fixed based on the avialability of the cases and representative samples were taken from selected dairy farms within the study period. Accordingly, a total of 50 fecal samples were collected from diarheic dairy calves in selected dairy farms in the Mekelle and Wukro districts. 2.5. Sample Collection, Handling and Transportation Each diarrheic calf was individually identified and restrained by an assistant and kept fixed before the sampling procedures. A total of 50 fecal samples were collected aseptically from clinically diarrheic calves. Approximately 30 ml of fecal samples were collected directly from the rectum and put into sterilized universal screwed caped bottle and all samples were properly labeled with permanent markers. The specimens were put into ice box having ice pack and then transported to Mekelle University College of veterinary medicine microbiology laboratory for bacteriological analysis. Information on ecology, environment, management and host factors mainly (age, sex, type of diarrhea, method/ awareness/ time of colostrum feeding, management/ production system and medication/vaccination) that would be used in the analysis and interpretation were recorded for each individual calf during sampling. 2.6. Isolation and Identification of Bacterial Pathogens Associated with Calf Diarrhea Isolation and identification of bacterial pathogens were performed as per the procedures described by Marchant and Packer (1967), (ISO, 2002), (Hu et al. , 2010) and (Thorns et al ., 1992). 2.7.1 Isolation and identification of Salmonella species Salmonella species were isolated and identified according to the techniques recommended by the International Organization for Standardization (ISO, 2002; Quinn et al. , 2004). Accordingly, the detection of salmonella in fecal samples was conducted in four stages: Non-selective pre-enrichment Buffered peptone water (BPW) was used at ambient temperature with the test portion of about 25ml of fecal sample which was measured using a sterile measuring cylinder. Each sample was put into sterile universal bottle, and 225 ml of BPW was added and mixed thoroughly using vortex mixer and incubated overnight at 37°C (ISO, 2002). Selective enrichment The pre-enrichment broth after incubation was mixed and 0.1 ml of the broth was transferred aseptically into a tube containing 10 ml of Rappaport-Vassiliadis medium (RV broth) and, another 1 ml of the pre-enrichment broth was transferred in to a tube containing 10 ml of Muller-Kauffmann tetrathionate broth (MKTT).The inoculated RV and MKTT broths were incubated at 42°C for 24 ± 3 hours at 37°C for 24 ± 3 hours respectively (ISO, 2002). Selective plating out and identification From the RV broth and MKTT broth cultures, selective solid media namely Xylose lysine deoxycholate (XLD) agar was used for plating out and identification purpose. A loop-full of inoculums from the RV broth and MKTT was streaked onto the surface of xylose lysine deoxycholate agar prepared in two separate Petri dishes. The plates were incubated at 37°C for 24 hours. After proper incubation, the plates were examined for the presence of suspected Salmonella colonies, which appeared pink with a darker pink center on XLD agar (ISO, 2002). Confirmation Suspicious colonies were further sub cultured in nutrient media for biochemical tests. Biochemical tests : All suspected non-lactose fermenting Salmonella colonies were picked from the nutrient agar and inoculated into the following biochemical tubes for identification: triple sugar iron (TSI) agar, Simmon’s citrate agar, urea broth, tryptone soya broth, MR-VP broth and then incubated for 24 to 48 hours at 37 o C. Triple Sugar Iron Agar (TSIA), Urease, Citrate, Indole, Methyl red and Voges Proskauer (VP) tests were done. Colonies producing red slant (alkaline), with yellow butt (acid) on TSI with blackening (H 2 S- hydrogen sulphide production) and bubbles (gas production) in butt, negative for urea hydrolysis (yellow), positive for citrate utilization (deep blue slant), negative for tryptophan utilization (indole test) (yellow-brown ring), positive for Methyl red and negative for Voges-Proskauer (VP) test were considered to be salmonella positive (ISO 6579, 2002; Quinn et al. , 2004). Isolate presumptive of salmonella for all biochemical tests were cultured on Nutrient Agar (NA) for antimicrobial susceptibility testing. 2.7.2. Isolation and identification of Escherichia coli Bacteriological culturing and examination : All samples were cultured on blood agar and incubated aerobically at 37°C for 24-48hrs. After colony morphological examination, type of hemolytic, and gram staining characteristics pure colonies were further sub cultured on nutrient and MacConkey agars for 24-48hrs at 37°C. The presence of growth on MacConkey agar was used as primary criteria to proceed for isolation and identification of E. coli . Furthermore, the colony characteristics observed on MacConkey agar was used to classify suspected bacteria isolated into two groups: lactose fermenter and non-lactose fermenter. Suspected E. coli colonies were presumptively identified their lactose fermenting character (pink colonies). Suspected E. coli were further sub cultured in Eosin methyl blue (EMB) agar medium for further identification. The characteristic colonies on EMB were identified based on green metallic sheen or blue-black to brown color. All isolated colonies were preserved on nutrient agar for further biochemical tests. Primary identification of bacterial isolates All isolates were checked for purity using gram staining technique and primary biochemical tests including Oxidase test, Catalase test and Oxidation-fermentation tests. Bacterial isolates that showed a positive result on Catalase tests, negative result on oxidation test and fermentative up on O-F test were presumed to be members of Enterobacteria and were used for further studies. Secondary identification of bacterial isolates Isolated bacterial pathogens with specific cultural characteristics of E. coli were maintained on nutrient agar, and subjected to biochemical tests such as Methyl red (MR), Vogues Proskauer (VP) test, Indole test, Citrate test, and Urease test (Marchant and Packer, 1967). 2.7.3. Isolation and identification of pathogenic Staphylococcus aureus Bacteriological culturing and examination A loop full of fecal sample was streaked on 5% sheep blood agar and the plates were incubated aerobically at 37°C and examined after 24 hrs of incubation for growth. The colonies were provisionally identified on the basis of staining reaction with Gram's stain, cellular morphology and hemolytic pattern on blood agar. Primary and secondary identification of bacterial isolates The culture colonies were sub cultured on nutrient agar and incubated at 37°C for 24 hrs for primary and secondary identification of Staphylococcus aureus . The isolated colonies from nutrient agar were exposed to Catalase test,Citrate utilation test and Methyl-red test. Colonies were grown on manitol salt agar grow and produce yellow color colony and S. aureus were isolated for anti-microbial susceptibility testing (Quinn et al ., 2004). 2.8. Antimicrobial Susceptibility Test The antibiotic susceptibility tests of Salmonella species, Staphylococcus aureus and Escherichia coli isolates were performed according to the National Committee for Clinical Laboratory Standards (NCCLS) method using Kibry-Bauer disk diffusion test on Muller-Hinton agar (CLSI, 2014). Pure colonies from nutrient agar were taken with a wire loop and transferred to a tube containing 5 ml of Saline water, emulsified and the turbidity was compared with 0.5 McFarland turbidity standards. Sterile cotton swab was dipped into the suspension and the bacteria were swabbed uniformly over the surface of Muller- Hinton agar plate within a sterile bio-safety cabinet. The plates were held at room temperature for 15 minutes to allow drying. Antibiotic discs with known concentration of antimicrobials were placed at equal distance and the plates were incubated at 37°C for 24 hrs. Each isolate was tested for a series of nine different antimicrobials. Following incubation, the diameters of clear zones produced by antimicrobial inhibition of bacterial growth were measured and recorded to the nearest mm for each disc using transparent digital caliper and then classified as resistant, intermediate or susceptible/sensitive according to published interpretive chart of (CLSI, 2014). 2.9. Data Management and Analysis Data collected from both field and laboratory were recorded in the format developed for this purpose and later on entered into the Microsoft excel 2013 program and analyzed using STATA 13 software. It was summarized by descriptive statistics and then displayed by tables to illustrate the relationships between the dependent variables (Salmonella species, Staphylococcus aureus and Escherichia coli isolates) and their total and independent variables (age, sex, type of diarrhea, method/ awareness/ time of colostrum feeding, management/ production system and medication/vaccination). Association of host risk factors with culture positives isolates was calculated. Antibiotic efficacy was determined by comparing zone of inhibition of each drug with the standard. 3. RESULTS 3.1. Bacterial Isolation and Identification 3.1.1. Frequency of isolation of E. coli , Salmonella species and Staphylococcus aureus Fecal samples were examined for the presence of E. coli, Staphylococcus aureus and Salmonella species using standard bacteriological techniques. The present finding indicated that E-coli was detected in 19(50%) where as Salmonella species and Staphylococcus aureus were detected in 12(31.6%) and 7(18.4%) respectively from the total samples of diarrheic calves examined, as summarized in Fig. 2 . 3.1.2. Association of E. coli , Salmonella species and Staphylococcus aureus with different risk factors During the present study association among the factors with the isolates was done as shown in Table 3 . Seventy five percent of E. coli were isolated from the age group of 9 up to 12 months where as 40% of Salmonella species isolates were found from age group of 6–9 months and 23.5% of Staphylococcus aureus were isolated from age group of 3–6 months. Most of the isolates of E. coli (37.8%), Salmonella species (29.7%) were found from female calves whereas 15.4% of isolates Staphylococcus aureus were found from male calves. Majority of the calf owner have the awareness on the importance of colostrum feeding. Most of the E. coli (54.6%) and Salmonella species (27.8%) isolates were found from the dairy calves whose owners don’t have awareness about colostrum feeding. Hand feeding was the most common method of colostrum feeding and most of the owners feed their calves within the first 6 hours after birth. About 16.7% Staphylococcus aureus was isolated from hand fed calves. However, 42% of E. coli , 28.6% salmonella species were isolated from calves that suckle directly from their dam. On the basis of time of colostrum feeding, E. coli (45.5%), Salmonella (27.8%) were found on those calves that took colostrum after 6 hours of birth. Regarding the treatment, 50% of E. coli , 25% Salmonella and Staphylococcus aureus were isolated from those calves who didn’t take any treatment within the study period. Similarly, relatively higher E. coli (50%), Salmonella (25%) and Staphylococcus aureus (14.3%) isolates were found from semi-intensive production system. Related to the type of diarrhea, 43.8% of E. coli were isolated from watery diarrhea, 28.6% of Salmonella species were isolated from bloody diarrhea and 21.4% of Staphylococcus aureus were isolated from mixed diarrhea. Table 1 The proportion of bacterial isolates with different risk factors Isolated Bacterial Species Varibles E.coli Salmonella spp. Staphylococcus aureus Categories N N (%) N (%) N (%) Age(months) ≤ 3 month 10 3(30) 1(10) 1(10) (3–6] 17 5(29.41) 3(17.67) 4(23.53) (6–9] 15 5(33.33) 6(40) 2(13.33) (9–12] 8 6(75) 2(25) 0(0) Sex Female 37 14(37.84) 11(29.73) 5(13.51) Male 13 5(38.46) 1(7.69) 2(15.38) District Mekelle 21 8(38.10) 7(33.33) 2(9.52) Wukro 29 11(37.93) 5(17.24) 5(17.24) Awareness of colostrum feeding Yes 39 13(33.33) 9(23.08) 7(14) No 11 6(54.55) 3(27.27) 0(0) Method of colostrum feeding Suckling 14 6(42.86) 4(28.57) 1(7.14) Hand feeding 36 13(36.11) 8(22.22) 6(16.67) Colostrum feeding time Before 6 hrs 28 9(32.14) 6(21.43) 6(21.43) After 6 hrs 22 10(45.45) 6(27.27) 1(4.55) Treatment status Treated 26 7(26.92) 6(23.8) 1(3.85) Non-treated 24 12(50) 6(25) 6(25) Production system Intensive 22 5(22.73) 5(22.73) 3(13.64) Semi-intensive 28 14(50) 7(25) 4(14.29) Type of Diarrhea Watery 16 7(43.75) 3(18.75) 2(12.50) Bloody 7 3(42.86) 2(28.57) 0(0) Mucoid 13 4(30.77) 3(23.08) 2(15.38) Mixed 14 5(35.71) 4(28.57) 3(21.43) 3.1.3. Biochemical profile of the bacterial isolates As indicated in Table 3 , on the basis of colony characteistics, all E.coli isolates were lactose fermenter on Macconkey agar, dark green metallic sheen colony on EMB agar and pink colored colony on Salmonella shigella agar whereas Salmonella species isolates were colorless on Macconkey and shamonella shigella agar and doesn’t grow on EMB agar. All Staphylococcus aureus isolates were grown on Mannitol salt agar with yellow colony. On the basis of biochemical tests, Both Salmonella species and E.coli isolates were postive for methyl red test and motile on SIM media whereas they were negative on citrate utilization test. Further more, hydrogen sulphide production was observed only by the isolated salmonella species. All E.coli , Salmonella species and Staphylococcus aureus isolates were catalase and Methyl red positive. Staphylococcus aureus isolates were β-hemolytic on blood agar, fermentative on O-F basal media and utilized sodium citrate on citrate utilization test. Table 2 Gram reaction, Colony and Biochemical characterstics of the isolated bacteria Variable Characteristics of the isolated bacteria E.coli (19) Salmonella spp. (12) S. aureus (7) Colony characteristics Macconkey agar Lactose fermenter (Pink) Colorless No growth EMB agar Methalic sheen colony No growth No growth Salmonella shigella agar Pink colour Colourless No growth Manitol salt agar No Growth No Growth Yellow Hemolytic character Negative Hemolytic β-Hemolytic Gram reaction Negative Negative Postive Biochemical tests Catalase test Postive Postive Postive Motility: Postive Postive Negative O-F test: Fermentative Non- Fermentative Fermentative H 2 S production Negative Postive Negative Indole test Postive Negative Negative Citrate utilization test Negative Negative Postive Methyl red test Postive Postive Postive 3.2. Antimicrobial Susceptibility Test Antimicrobial susceptibility testing was performed for all of the bacteria isolated from the diarrheic calves and the result was as presented in Table 3 below. Most of E.coli , Salmonella species and Staphylococcus aureus isolates were sensitive to Streptomycin, Polymyxin-B and Gentamycin. However, most of E.coli , Salmonella species and Staphylococcus aureus isolates were resistant to Clindamycin, Kanamycin and Methicillin. Detail antimicrobial susceptibility profiles of the isolated bacteria against the tested antibiotics is indicated in Table 3 . Table 3 Antimicrobial susceptibility pattern of E. coli, Salmonella spp and Stapylococcus aureus isolated from diarheic calves Antimicrobial discs Species of bacteria E. coli (N = 19) N (%) Salmonella spp. (N = 12) N (%) Staphylococcus aureus (N = 7) N (%) S I R S I R S I R Pencillin G 5 (26.3) 4(21.1) 10(52.6) 2(16.7) 2(16.7) 8(66.7) 4(57.1) 2(28.6) 1(14.3) Steptomycin 10(52.6) 5(26.3) 4(21.1%) 7(58.3%) 2(16.7) 3(25) 5(71.4) 1(14.3) 1(14.3) Clindamycine 4(21.1) 6(31.6) 9(47.4) 3(25%) 4(33.3) 5(41.7) 2(28.6) 4(57.1) 1(14.3) Kanamycin 7(36.8) 2(10.5) 10(52.7) 3(25) 3(25) 6(50) 1(14.3) 2(28.6) 4(57.1) Vancomycin 9(47.4) 7(36.8) 3(15.8) 3(25) 2(16.7) 7(53.8) 3(42.9) 2(28.6) 2(28.6) Polymyxin-B 14(73.7) 2(10.5) 3(15.9) 7(58.3) 2(16.7) 3(25) 5(71.4) 1(14.3) 1(14.3) Gentamycin 15(78.9) 2(10.5) 2(10.5) 8(66.6) 2(16.7) 2(16.7) 4(57.1) 2(28.6) 1(14.3) Erythromycin 3(15.8) 7(36.8) 9(47.4) 3(25%) 4(33.3) 5(41.7) 5(71.4) 1(14.3) 1(14.3) Methicillin 4(21.1) 7(36.8) 8(42.1) 4(33.3) 4(33.3) 4(33.3) 2(28.6) 2(28.6) 3(42.9) N- Number, S-Susceptible, I-Intermediate and R-Resistance 4. DISCUSSION In the current study, an attempt has been made to isolate and identify E. coli , Salmonella species and Staphylococcus aureus from calves suffering from diarrhea, to identify the associated risk factors and also to determine the antibacterial susceptibility patterns of those isolated E. coli in selected dairy farms located in Mekelle and Wukro. Various study findings revealed that calf diarrhea is major health problems in dairy farms via causing high mortality and morbidity of calves. In addition, calf diarrhea has played a great economic loss like money spent on treatment costs, loss of genetic potential both from the loss of calves and reluctance of farmer to invest in higher price semen in the face of calf mortality problem, also impair appropriate heifer replacement (Svenson et al ., 2003) and this influence the ability of dairy men to increase production by allowing them to practice selective culling of low productive cows. Out of 50 faecal samples, 38 bacteria were isolated and 19(50%) were postive for E.coli giving lactose fermentation on MacConkey agar plate, methalic green sheen colonies on EMB plates and pink color colony on Salmonella Shigela agar plate whereas 12(31.6%) samples were found postive for Salmonella species, giving negative reaction to lactose fermentation on MacConkey agar plate and Salmonella species produce translucent and colorless colonie on s Salmonella Shigela agar plate. 7(18%) samples were postive for stoaphlococcous producing yellowish colonies on Manitol salt agar and beta hemolysis on Blood agar. Differences in colony morphology manifested by the isolates may be due to to loosing or acquiring some roperties by the transfer of host or choice of host tissue as observed by Dubreuil et. al (1991). The isolated E. Coli, Staphylococcus aureus and Salmonella species showed identical result in different biochemical test including sugar fermention, Indole test, H 2 S production test, Citrate utilization test, Motility and methyl-red test. It is reported that more than one predisposing factor such as environmental and managment factors (housing, climate) inbalance nutrition, immune status of the calves might help in the production of calf diarrhea along with the presence of one or more than one type of bacteria (Fouquet, 1979 and Debnath et al. , 1987). The result of frequency distribustion of bacterial isolates are presented Out of 50 faecal samples, 19 (50% ) Sample were postive for E. Coli, 12 (31.6%) samples were postive for Salmonella spp., 7 (18.4%) postive for satphylococcus spp., were found in the fecal calf diarrhea. Result of present study indicated that all the three different type of bacteria were present in the faecal sample collected from diarrheac calves. The incidence of different type of bacteria isolated from calve diarrhea, correlated with the finding of Raseswari shomel et al. (1996). Haque samad ( 1996) isolated 9.61% Salmonella from calves, Joon and Kaura (1993) isolated 23 (23%) E.coli and 5 (5%) Salmenella from 100 facecal samples. This variation in the occurrence of the bacterial isolates could come from the difference in climatic conditions, sample size, variations in age groups examined (sample collected), feeding managements, environment condition, and poor hygiene often allows buildup of pathogenic strains in young animal’s environment. In the present study, an attempt has been made to isolate and identify E. coli Salmonella species and Staphylococcus aureus associated with calf diarrhea, as well as investigation of the potential risk factors, which could influence the occurrence of calf diarrhea. In addition, determination of antimicrobial susceptibility of the bacterial isolates was conducted. The research was comducted to isolate, identfy and characterised the bacterial pathogens causing calf diarrhea in Mekelle city and Wukro town Tigray, Ethiopia. A total sample 50 faecal samples were collected and examined bacteriologicaly for the isolation, iydentificatin, frequency distribustion, and antimicrobial susceptibility test for the isolated pathogenic bacteria from calve diarrhea. the result of isolation and iydentrificationof E. Coli, salmonella spp and stapyloccus spp. The patogenic bacteria charactrised using by Gram staining, cultural bioichemical test. Out of 50 faecal samples 19 were postive for E.coli giving lactose fermentation on MacConkey agar plate,methalic green sheen colonies on EMB plates and pink color colony on salmonella shigela agar plate. 12 samples were found postive foe salmonella spp,giving negative reaction to lactose fermentation on MacConkey agar plate.and salmonella spp produce translucent and colorless colonie on s-s agar plate. 7 samples were postive for stoaphlococcous producing yellowish colonies on Manitol salt agar and hemolysis on Blood agar.Differences in colony morphology manifested by the isolates may be due to to loosing or acquiring som properties by the trans fer of host or choice of host tissue as observed by Dubreuil et al. (1991). The isolated E. Coli, Staphylococcus and Salmonella showed iydentical result in different biochemical test including sugar fermention, Indole test,H 2 S production test,Citrate utilization test, Motility and methyl-red test. It is reported that more than one predisposing factor such as environmental and managment factors (housing, climate) inbalance nutrition, immune status of the calves might help in the production of calve diarrhea along w ith the presence of one or more than one type of bacteria ( Fouquet,1979 and Debnath et,.1987). The result of frequency distribustion of bacterial isolates are presented Out of 50 faecal samples, 22 (44% ) Sample were postive for E. Coli, 14 (28%) samples were postive for Salmonella spp., 8 (16%) postive for satphylococcus spp., 9 ( 18%) samples were mixed infection and 6 (12%) samples were negative for bacteria. The frequency distribustion of different species of bacterial isolates in different faecal samples were found variable. Result of present study indicated that all the three different type of bacteria were not present in same faecal sample collected from diarrheac calves. The incidence of different type of bacteria isolated from calve diarrhea, correlated with the finding of Raseswari shomel et al. (1996). Haque samad ( 1996) isolated 9.61% Salmonella from calves, Joon and Kaura (1993) isolated 23 (23%) E.coli and 5 (5%) Salmenella from 100 facecal samples. The isolated pathogenic bacteria isoalated from calf diarrhea E.coli, salmenella spp, and staphylococcus spp, were correlated with finding of Abdullah et al.,(21013). Atotal 114 faecal samples was collected from diarrhic calf diarrhea out of thsese, 44 (38.6%) samples were postive for E.coli, 25 (21.9%) samples were postive for Salmonella spp., 15 (13.2%) samples were postive for Staphylococcus aureus , 18 (15.8%) samples wre mixed infection and 12 (10.5%) samples were negative for bacteria. 5. CONCLUSION AND RECOMMENDATIONS Out of the 50 fecal samples colected from diarheic calves, 76% were found harboring one or more GI bacteria at varying levels. E.coli , Salmonella species and S.aureus were isolated at a rate of 50%, 31.6% and 18.4% repectively from the diarheic dairy calves in the study districts. It was found that age, method of colostrum feeding, colostrum feeding time and production system were associated with higher bacterial isolation and occurrence of calf diarrhea. Accordingly, higher bacterial species were isolated from 6–9 months old calves mnaged in semiextensive production system which consumed colostrum after 6 hrs of birth. Majority of the dairy farm owners have awarenes on the importance of colostrum feeding. The antibiogram conducted in the current work has shown an increased level of resistance among the isolated bacteria against the commonly used antibiotic drugs. Most of E.coli , Salmonella species and Staphylococcus aureus isolates were sensitive to Streptomycin, Polymyxin-B and Gentamycin. Therefore, based on the above concluding remarks the following points are recommended: The extension works to improve care to calves and ensuring ingestion of adequate colostrum as early as 24 hour of life is the best way of giving calves a good start to life and is crucial to reduce calf diarrhea. Further characterization and potential effect of the isolated bacteria on the health and productivity of the calf needs to be studied further. Diarrhea in calves is caused by the synergistic effect of predisposing factors. Hence, further studies should be carried out to look in the role of viruses, parasites, fungi and anaerobic bacteria as primary or secondary causes of calf diarrhea. In consideration of the most effective in-vitro antibacterial agents against the isolated bacteria, Streptomycin, Polymyxin-B and Gentamycin should be the drugs of choice in controlling diarrhea in calves. Declarations Animal Ethics Statement for Preprint Ethical clearance was obtained prior to conducting the study from the Mekelle University, College of Veterinary Sciences Research Ethics Review Committee (RE: Notification of Protocol Approval No. MU-IRB2156/2024). All animal handling and experimental procedures were carried out in accordance with accepted ethical guidelines for the care and use of animals. Efforts were made to ensure animal welfare and to minimize stress, discomfort, and suffering throughout the study. References CLSI. (2014): Performance standards for antimicrobial susceptibility testing. CLSI document M100-S24. Wayne, PA: Clinical and Laboratory Standards Institute; 65. Quinn, P. J., Carter, M. E., Markey, B. and Carter, R. G. (2005): Clinical Veterinary Microbiology, 7th edition, (Elsevier Health Science Ltd., Philadelphia). Quinn, P. J., Markey, B. K., Carter, M. E., Donnelly, W. J. and Leonard, F. C. (2002): Veterinary Microbiology and Microbial Disease, Black well Science, pp 137–143. ISO 6579 (2002). Microbiology of food and animal feeding stuff: horizontal method for the detection of Salmonella spp . Geneva, 511–525. Thorns, C., Bell, M., Chasey, D., Chesham, J. and Roeder, P. (1992). Development of monoclonal antibody ELISA for simultaneous detection of bovine coronavirus, rotavirus serogroup A, and Escherichia coli K99 antigen in feces of calves. Am. Vet. Res. , 53 :36–43. Hu, X., Li, L., Cao, Y., Zhang, J., Gong, M. and Yang F. (2010). “Isolation and identification of a phosphate-solubilizing bacterium Pantoea stewartii subsp. stewartii g6, and effects of temperature, salinity, and pH on its growth under indoor culture conditions.” Aqua. Inter ., 18 (6): 1079–1091. Merchant, I. and Packer, R. (1967). Veterinary Bacteriology and Virology 6th Ed., Iowa State University Press USA, 128–133. Elham, I., Atwa-Eman, M., Sharaf, and Eman, M. (2012).Bacterial Diarrhoea in Newly Born Calves in Menoufiea Governorate. Assiut Vet. Med. , 58 : 135. Aiello, S. E, May, A. (1998): The Merck Veterinary Manual. 8th edition. New Jersey. USA: Merck and Co, Inc, Pp. 1053–1057. Lobago, F. B. Bekana, H. Gustafsson and H. Kindahl, (2006): Reproductive performance of dairy cows in small holder production system in selalle, Central Ethiopia. Trop. Anim. Prod. Health , 38 : 333–342. Central Statistical Agency, (2009): The Federal democratic republic of Ethiopia Central Statistical Agency, agriculture in figure key findings of the 2008/09-2010/11 agricultural sample surveys for all sectors and seasons Country Summary, FDRECSA Addis Ababa, Ethiopia, Pp.: 14–18. Abdisa B. and Minda A. (2016). Major Calf Health Problems and Exposing Risk Factors at Holeta Agricultural Research Center Dairy Farm, Holeta, Ethiopia. Journal of Global Veterinaria , 17 (1): 05–14. Achá, S., Kühn, I., Jonsson, P., Mbazima, G., Katouli M. and Möllby R. (2004): Studies on Calf Diarrhoea in Mozambique: Prevalence of Bacterial Pathogens Acta Vet. Scand. 45 (1): 27–36. Amaha, K. (2002): An Integrated Urban, Peri- Urban and Rural Dairy Development Program in Tigray .Diary animal health project (Final Report). Asefa A., Asmare W. and Ashenafi K.(2016). Dairy calf morbidity and mortality and associated risk factors in Sodo town and its suburbs, Wolaita zone, Ethiopia. Slovak Journal Animal Science , 49 (1): 44–56. Bazeley, K. (2003). Investigation of diarrhea in the neonatal calf. In practice, 25: 152–159. BOANR (1997): Tigray Livestock development action program main report, Vol.1. bureu of Agriculture and Natural Resourses, Mekkelle, Tigray .Pp. 1–10. ChoY. And Yoon K. (2014). An overview of calf diarrhea-infectious etiology, diagnosis, and intervention. Journal of Veterinary Science, 15 (1):1–17. Clinical and laboratory standards institute (2006). Performance standareds for antimicrobial disk susceptibility testing. 16th informational supplement. M100-S16. Wayne, Pa. CSA (Central Statistics Authority), 20010/11. Agricultural sample survey 2010/2011. Vol. II. CSA. DACA, (2006): Standared veterinary treatment guide lines for vet.Practice 1st ed DACA. Addis Ababa, Ethiopia. Efficiency of Boss indicus (Zebu) cows under artificial insemination. Amin. Report. Sci. 24:63–72 Elham I., Atwa. Eman M., Sharaf and Eman M. (2012). Bacterial Diarrhoea in Newly Born Calves in Menoufiea Governorate. Journal of Assiut Veterinary Medicine , 58 : 135. Halderman, M.N. 2004. The political economy of pro-poor livestock policy making in Ethiopia . FAO working paper No. 19. Rome: FAO. Hemashenpagan N; B. Kiruthiga; T. Selvaraj and A. Panneerselvam, (2007). Isolation, Iydentification and Characterization of Bacterial pathogens causing Calf diarrhea with special reference to Escherichia coli. The intrnat journal of Microbiology, 7(2), DOI: 10.5580/9c7. ILCA, (1998): Animal reproduction for for African counties, Report of ajoint ajiont seminar bi internationl foundation for science and Swedish international program on animal production. ILCA, Addis Ababa, Ethiopia. Lemma,M, Kasha T, Azage T(2001) Clinically manifesed major health problems of cross breed dairy breeds in urban and peri-urban production systems in central highlands of Ethiopia TROP Animal health Prod 33(2):85–93 OIE (Office International Des Epizooties ) (200).Manual of standards for diagnostics test and vaccine. OIE Guide − 2. OFED(Office of Finance and Economic Development), 2008. Socio-economic statistical abstract, Wukro,Tigray. Prescott B., Kee M., Glock R., Cuneo P., Young D., Reggiardo C., Trinh H., and Songer J. (2008): A possible role for Clostridium difficile in the etiology of calf enteritis. Journal of Veterinary Microbiology , 127 (3–4): 343–352. Radostits, O,M; D.C. Blood and G.c. Gay (2000). Veterinary Medicine : Atext Book of the Disease of Cattle, Sheep, Pig, Goat and Horse. 8th Edn.W.B. Saunders Company, philadelphia, London. Report on livestock and livestock characteristics. Statistical Bulletin. Addis Ababa, Ethiopia: Additional Declarations The authors declare no competing interests. Supplementary Files MeleeeeethesisFinalEditionbyMGS.doc IMG20240805100804.jpg IMG20240805100755.jpg IMG20240805100710.jpg IMG20240805100656.jpg IMG20240805100649.jpg IMG20240805100637.jpg IMG20240805100629.jpg IMG20240805100508.jpg IMG20240805100506.jpg IMG20240805100459.jpg Antimicrobialtest.jpg Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8512251","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":568990677,"identity":"5645ae1b-5273-4aa7-a35d-649cab8d010c","order_by":0,"name":"Melesew Adisu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIiWNgGAWjYFAC5gYIfRiIP4BZCYS0MCK0MM6Aa8GrDablANBCHmK06LY3Nj78UcEgz3ec/Zm0bc5hBn72HAOGjz9wazE7c7DZmOcMg+HMwzxm0rnbDjNI9rwxYJyBxxazG4lt0oxtDIwbDvOwgbUY3MgxYObBp+X+w/afP/8x2G84DHSYJVCLPUjLH7y2AK3gbWBI3HCYwUyaEWSLBFALPu+bnUlsluY5JpEM9IuxZe+2dB6JM88KDvak4dFy/PDBjz9qbGz7zh9/eOPnNms5/vbkjQ9+2ODWAgUScBY4ag4Q1DAKRsEoGAWjAC8AAH0UUfjhxvy/AAAAAElFTkSuQmCC","orcid":"","institution":"College of Veterinary science,Mekelle University po. Box. 231","correspondingAuthor":true,"prefix":"","firstName":"Melesew","middleName":"","lastName":"Adisu","suffix":""},{"id":568991046,"identity":"6124cf07-e8e4-494e-96ee-70beaa9f9cb1","order_by":1,"name":"Girmay Hiluf","email":"","orcid":"","institution":"College College of Veterinary science, Mekelle Univesity Po. Box. 231","correspondingAuthor":false,"prefix":"","firstName":"Girmay","middleName":"","lastName":"Hiluf","suffix":""},{"id":568991114,"identity":"1d5993ad-f857-4c8a-8045-20cce48c08ca","order_by":2,"name":"Abrhet Alem","email":"","orcid":"","institution":"College of Veterinary Science,Mekelle Univesity","correspondingAuthor":false,"prefix":"","firstName":"Abrhet","middleName":"","lastName":"Alem","suffix":""}],"badges":[],"createdAt":"2026-01-04 10:16:47","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":true,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":true},"doi":"10.21203/rs.3.rs-8512251/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8512251/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":100358505,"identity":"f430e09d-a9d7-4636-a23e-28d57d0af82e","added_by":"auto","created_at":"2026-01-16 07:21:07","extension":"doc","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":556032,"visible":true,"origin":"","legend":"","description":"","filename":"AbrhaMelesewmanuscriptA.doc","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/58c6e71e2bf4b438e53ff423.doc"},{"id":99866482,"identity":"f2a7aeff-27f6-438c-afd5-ed59de7cd07a","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":342,"visible":true,"origin":"","legend":"","description":"","filename":"rs8512251.json","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/384e73852734e6d8528a5741.json"},{"id":100357877,"identity":"55b30f16-f546-4eae-8a8b-841e3cd33cc0","added_by":"auto","created_at":"2026-01-16 07:20:27","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":88612,"visible":true,"origin":"","legend":"","description":"","filename":"rs85122510enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/ecc5c1edb5da156e8c2e39f5.xml"},{"id":99866486,"identity":"99c141d6-d6b1-47f7-83ff-3b46091fc7a7","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"png","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":24749,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/3166ca4486057d57b8abeafb.png"},{"id":100358572,"identity":"8d51cb9b-47ff-4c07-ba2c-06006cbb7b9c","added_by":"auto","created_at":"2026-01-16 07:21:10","extension":"png","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":10406,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/eaac530261a172d6e6055f10.png"},{"id":99866495,"identity":"04a99781-5e00-4db0-877b-148d6430dc11","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"xml","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":87402,"visible":true,"origin":"","legend":"","description":"","filename":"rs85122510structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/666cd36966023f2ae5ce4cec.xml"},{"id":99866499,"identity":"61511b19-c8d3-4cf4-8e27-2dd0f6ea8934","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"html","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":95011,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/5502740ca8b5a8189c4ca7e5.html"},{"id":99866481,"identity":"d8ede6dc-8b69-4c81-98b7-29aecef95569","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":132538,"visible":true,"origin":"","legend":"\u003cp\u003eMap of the study area\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSource:\u003c/strong\u003e (ArcGIS, 2012).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/0b66735a6570c5b2e217f82c.png"},{"id":99866484,"identity":"f78f0866-d321-40a7-96fc-20e425abcc95","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":60509,"visible":true,"origin":"","legend":"\u003cp\u003eFrequency of bacterial isolates from total examined samples\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/7faaa45f896778cbe937ce26.png"},{"id":100377036,"identity":"86407136-acf1-4a1a-b30f-a64356b7c325","added_by":"auto","created_at":"2026-01-16 08:46:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1510562,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/c1efb4c9-2086-4fe5-ac1f-57e7bf249bf0.pdf"},{"id":99866483,"identity":"1109a204-bfab-4388-bfcb-d8ac23e3fce2","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"doc","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":875008,"visible":true,"origin":"","legend":"","description":"","filename":"MeleeeeethesisFinalEditionbyMGS.doc","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/6406a09f60db24be1e753a13.doc"},{"id":99866488,"identity":"7b5403bc-5a67-43a8-95ee-b5ff0c6386e3","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":1285322,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100804.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/23bbae1793176c2d926233c8.jpg"},{"id":100357895,"identity":"d1b59d18-6db3-4c62-ab47-84faea0035f4","added_by":"auto","created_at":"2026-01-16 07:20:28","extension":"jpg","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":1305269,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100755.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/fa3d9123c949d1f90149e05c.jpg"},{"id":99866496,"identity":"a402c649-3f9f-4558-8132-31acd7b8803d","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"jpg","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":1306798,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100710.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/0f578c50f09a6a9bac408eee.jpg"},{"id":99866492,"identity":"a7082076-2c13-492b-bd5a-9fc39adc5299","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"jpg","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":1379543,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100656.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/d5d1ab12f25694816d151412.jpg"},{"id":100357352,"identity":"194db499-cdcb-49ac-93c0-49bc758f5b27","added_by":"auto","created_at":"2026-01-16 07:19:44","extension":"jpg","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":1422721,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100649.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/b7f8220897d04ae06041510a.jpg"},{"id":100358282,"identity":"11a60454-ef5e-4833-98c5-e0307be3c0b0","added_by":"auto","created_at":"2026-01-16 07:20:51","extension":"jpg","order_by":7,"title":"","display":"","copyAsset":false,"role":"supplement","size":1497305,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100637.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/1f2669ef353c022ff9a43e80.jpg"},{"id":100357741,"identity":"d0078e49-b551-44f5-8535-fada1c344367","added_by":"auto","created_at":"2026-01-16 07:20:16","extension":"jpg","order_by":8,"title":"","display":"","copyAsset":false,"role":"supplement","size":1462507,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100629.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/c811886b635b94b2b94855bd.jpg"},{"id":99866491,"identity":"edd1295f-be68-4f51-bbba-05f17aee6f40","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"jpg","order_by":9,"title":"","display":"","copyAsset":false,"role":"supplement","size":1401756,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100508.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/1e298d4cbf2c8a353d88e1ea.jpg"},{"id":99866500,"identity":"49bf03be-6025-4971-8035-cc5a825773c6","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"jpg","order_by":10,"title":"","display":"","copyAsset":false,"role":"supplement","size":1385681,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100506.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/bc48f4ff2d51298e036dc731.jpg"},{"id":99866490,"identity":"0248d7db-69bb-4f12-bf1e-b3eb8517d31c","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"jpg","order_by":11,"title":"","display":"","copyAsset":false,"role":"supplement","size":1257562,"visible":true,"origin":"","legend":"","description":"","filename":"IMG20240805100459.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/1644573317f8aa3ad9f18e3c.jpg"},{"id":99866501,"identity":"e184d39a-6554-493f-a1d8-37a88bc29443","added_by":"auto","created_at":"2026-01-09 08:17:42","extension":"jpg","order_by":12,"title":"","display":"","copyAsset":false,"role":"supplement","size":1427862,"visible":true,"origin":"","legend":"","description":"","filename":"Antimicrobialtest.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8512251/v1/54b9972cb9a6a2c3424e2d93.jpg"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eIsolation and Antimicrobial Sensitvity pattern of Salmonella species, Staphylococcus aureus and Escherichia coli from diarrheic dairy calves in selected dairy Farms of Mekelle and Wukro, Tigray, Northern Ethiopia.\u003c/p\u003e","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eEthiopia has very large livestock populations with diverse genetic makeup inhabiting diverse agro-ecological zones (Aiello and May, 1998). Estimates for farmer holding in rural areas indicate that the country has about 50.9\u0026nbsp;million heads of cattle, 22\u0026nbsp;million goats, 26.0\u0026nbsp;million sheep and 2.3\u0026nbsp;million camels (CSA, 2010/11). In Ethiopia, livestock plays multiple economic and social roles. On the basis of statistics acquired from different sources, livestock sector offers about 16% of the total GDP that is equivalent to 40% of total agricultural GDP excluding the values of draught power, transport and manure and contributes to the livelihoods of about 60\u0026#150;70% of the Ethiopian population and generates 14% of the country\u0026#146;s foreign exchange earnings (CSA, 2009; Halderman, 2004).\u003c/p\u003e \u003cp\u003eIn Sub Sahran Africa livestock plays a curcial role in economic development of the countries and living standared of rural communities by serving as source of income and food. Export of live animals and animal products make substainal contribution to the foriegn exchange earnigs of many countries (ILCA, 1998). As in many other countries, livestocke play multiple roles in Ethiopia being a major natural source of feed, industrial raw materials, export earnings and form an integral part of the agriculture production system. However, thier productivity is low due to various constriants such as disease, poor nutrition, poor managment practies and low reproductive performance of the indigenous breeds (DACA, 2006; Lobago, 2006).\u003c/p\u003e \u003cp\u003eLivestock is an intergral parts of the agricultural production system in most countries and plays an important role in national economy as well as in socio-economic development of millions of rural household (Radostits \u003cem\u003eet al.\u003c/em\u003e, 2000). Dairy farming is a growing livestock production system in Ethiopia (Abdisa and Minda, 2016). Because of better availability of milk market in urban and peri-urban areas, dairy farms are concentrated in these areas of the country. A successful dairy farm operation requires that a large percentage of cows wean a live healthy calf every year. Rearing healthy dairy calves to weaning time requires maximizing the calf\u0026#146;s level of immunity against disease while minimizing its exposure to infectious agents. However, among the factors that have been hindering success of dairy industry, morbidity and mortality of calves is the one that causes major concern (Asefa \u003cem\u003eet al\u003c/em\u003e., 2016).\u003c/p\u003e \u003cp\u003eNeonatal calf diarrhea is one of the most common diseases in young animals, causing huge economic and productivity losses to bovine industry worldwide (Cho and Yoon, 2014). Diarrhoea in farm animals, especialy in neonatal calves is one of the most challenging clinical syndromes encountered by many practicing veterinary practitionners. Diarrhoea is a leading cause of economic losses to the cattle industry and major cause of calf mortality and morbidity during first few weeks of life in most countries (Radostits \u003cem\u003eet al\u003c/em\u003e., 2000).\u003c/p\u003e \u003cp\u003eCalf diarrhea is a multifactorial disease entity that can have serious financial and animal welfare implications in both dairy and beef herds. It has been estimated that 75% of early calf mortality in dairy herds is caused by acute diarrhea in the pre-weaning period (Sunday \u003cem\u003eet al.\u003c/em\u003e, 2016). Diarrhea is a well-known clinical sign in neonatal animals with complex etiology. Managemental, environmental, nutritional, physiological variations and variety of pathogens including bacteria, viruses, protozoa and intestinal parasites are described as important agents causing diarrhea in these animals (Elham \u003cem\u003eet al\u003c/em\u003e., 2012).\u003c/p\u003e \u003cp\u003eEnteropathogens have been recognized as major causes of diarrhea in calves. Enterotoxigenic \u003cem\u003eE. coli (ETEC)\u003c/em\u003e and Salmonella are known to be the most common and economically important bacterial agents (SJ Ach\u0026aacute; etselected \u003cem\u003eet al.\u003c/em\u003e, 2004). However, other bacteria, including Campylobacter, Staphylococcus and Clostridium spp. have also been identified as the cause of enteric disease and diarrhea in calves (Prescott \u003cem\u003eet al.\u003c/em\u003e, 2008). In acute neonatal diarrhea, an important disease of calves, four micro-organisms in particular, are of widespread occurrence and proven entero-pathogenicity: rotavirus, coronavirus, cryptosporidium and enterotoxigenic \u003cem\u003eE. coli\u003c/em\u003e (Elham \u003cem\u003eet al\u003c/em\u003e., 2016).\u003c/p\u003e \u003cp\u003eThe economic losses due to calf mortality and morbidity occur not only from mortality but also from treatment costs, subsequent chronic ill hrift and impaired growth performance (Bazeley, 2003). Overfeeding, overpopulation cold temperature bad hygienne, artificial feeding and colostrums deprivation are all predisposing factors which can be important in the complex etiology of the disease (Debnath \u003cem\u003eet al\u003c/em\u003e., 1987).\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eCurrently, the other major concern to animal and human health is the issue of antimicrobial resistance due to indiscriminate use of antibiotics in livestock production as well as human diseases conditions in developing countries. In Ethiopia, the major antibiotics used for treatment of animal and human diseases include Penicillin, Streptomycin, Gentamycin and Oxytetracycline. The indiscriminate use of these antibiotics leads to antibiotic resistance. Several fragmented studies conducted in different sectors magnify the problem of antibiotic resistance. Most therapeutic attempts are based on the tentative diagnosis of the disease and do not have rational basis to select effective antibiotics. Knowledge of the diversity and antibiotic sensitivity profiles of the etiologic agents is necessary for effective control of calf diarrhea. Hence, this study was carried out with the following objectives.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eTo isolate and identify Salmonella species, \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eEscherichia coli\u003c/em\u003e from diarrheic dairy calves in Mekelle and Wukro districts.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eTo determine the antimicrobial susceptibility patterns of the isolated bacteria against selected antibiotic discs.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"2. MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Study Area\u003c/h2\u003e \u003cp\u003eThe study was conducted from October, 2024 to February, 2025 in urban and periurban dairy farrms of Mekelle and Wukro districts, Tigray region, Northern Ethiopia.\u003c/p\u003e \u003cp\u003eMekelle is the capital city of Tigray regional state which is geographically located at 39\u003csup\u003e0\u003c/sup\u003e 29\u0026#146;E and 13\u003csup\u003e0\u003c/sup\u003e 30\u0026#146;N, and 783Km far from Addis Ababa. It is also located at an altitude of 2000 m.a.s.l. The mean annual rain fall of the study area is 628.8mm and rain is associated with the North and South oscillation of the inter-tropical conversion zone. The annual minimum and maximum temperature is 11.8\u003csup\u003e0\u003c/sup\u003eC and 29.9\u003csup\u003e0\u003c/sup\u003eC, respectively (BANRO, 1998).\u003c/p\u003e \u003cp\u003eWukro is one of the 47 weredas in Tigray situated in the Eastern Zone 45 kms far away north of Mekelle. The town is found at 2140-2250m above sea levels with a climate of Weina Degua. The total size of the town is 860 hectares, with comfortable environment for residential, has an average temperature of 19.730\u003csup\u003ec\u003c/sup\u003e and annual average rainfall of 690.25mm (OFED, 2008).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSource\u003c/strong\u003e \u003cp\u003e(ArcGIS, 2012).\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Study Animals\u003c/h2\u003e \u003cp\u003eThe study animals were cross breed dairy calves which are under twelve months old of both sexes, managed under differnt farming system located in Mekelle and Wukro districts. First the study animals were selected purposively and divided according to their location as urban (Mekelle and Wukro town) and peri-urban (the surrounding area within Mekelle and Wukro town). Fecal samples were collected from calves selected based on the diarrheic clinical signs.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1. Case definition\u003c/h2\u003e \u003cp\u003e \u003cstrong\u003eDiarrheic Calves\u003c/strong\u003e \u003cp\u003eare those with diarrhea and exhibiting signs of systemic disease such as increased rectal temperature, poor appetite, dehydration, decreased mentation, and reduced suckle reflex and had pasty\u0026#150;watery feces with different colors.\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Study Design\u003c/h2\u003e \u003cp\u003eA cross-sectional study was carried out from October, 2018 to February, 2019 to isolate and determine the antimicrobial susceptibility profile of Salmonella species, \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eEscherichia coli\u003c/em\u003e from feces of clinically diarrheic calves in Mekelle and Wukro districts.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Sample Size Determination and Sampling Technique\u003c/h2\u003e \u003cp\u003eThe dairy farms were purposively selected based on the accessibility and availability of diarheic calves. All calves fulfilling the inclusion criteria were considered for sampling. The sample size was fixed based on the avialability of the cases and representative samples were taken from selected dairy farms within the study period. Accordingly, a total of 50 fecal samples were collected from diarheic dairy calves in selected dairy farms in the Mekelle and Wukro districts.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Sample Collection, Handling and Transportation\u003c/h2\u003e \u003cp\u003eEach diarrheic calf was individually identified and restrained by an assistant and kept fixed before the sampling procedures. A total of 50 fecal samples were collected aseptically from clinically diarrheic calves. Approximately 30 ml of fecal samples were collected directly from the rectum and put into sterilized universal screwed caped bottle and all samples were properly labeled with permanent markers. The specimens were put into ice box having ice pack and then transported to Mekelle University College of veterinary medicine microbiology laboratory for bacteriological analysis.\u003c/p\u003e \u003cp\u003eInformation on ecology, environment, management and host factors mainly (age, sex, type of diarrhea, method/ awareness/ time of colostrum feeding, management/ production system and medication/vaccination) that would be used in the analysis and interpretation were recorded for each individual calf during sampling.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e2.6. Isolation and Identification of Bacterial Pathogens Associated with Calf Diarrhea\u003c/h2\u003e \u003cp\u003eIsolation and identification of bacterial pathogens were performed as per the procedures described by Marchant and Packer (1967), (ISO, 2002), (Hu \u003cem\u003eet al.\u003c/em\u003e, 2010) and (Thorns \u003cem\u003eet al\u003c/em\u003e., 1992).\u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.7.1 Isolation and identification of \u003cem\u003eSalmonella species\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eSalmonella species were isolated and identified according to the techniques recommended by the International Organization for Standardization (ISO, 2002; Quinn \u003cem\u003eet al.\u003c/em\u003e, 2004). Accordingly, the detection of salmonella in fecal samples was conducted in four stages:\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eNon-selective pre-enrichment\u003c/strong\u003e \u003cp\u003eBuffered peptone water (BPW) was used at ambient temperature with the test portion of about 25ml of fecal sample which was measured using a sterile measuring cylinder. Each sample was put into sterile universal bottle, and 225 ml of BPW was added and mixed thoroughly using vortex mixer and incubated overnight at 37\u0026deg;C (ISO, 2002).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSelective enrichment\u003c/strong\u003e \u003cp\u003eThe pre-enrichment broth after incubation was mixed and 0.1 ml of the broth was transferred aseptically into a tube containing 10 ml of Rappaport-Vassiliadis medium (RV broth) and, another 1 ml of the pre-enrichment broth was transferred in to a tube containing 10 ml of Muller-Kauffmann tetrathionate broth (MKTT).The inoculated RV and MKTT broths were incubated at 42\u0026deg;C for 24\u0026thinsp;\u0026plusmn;\u0026thinsp;3 hours at 37\u0026deg;C for 24\u0026thinsp;\u0026plusmn;\u0026thinsp;3 hours respectively (ISO, 2002).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSelective plating out and identification\u003c/strong\u003e \u003cp\u003eFrom the RV broth and MKTT broth cultures, selective solid media namely Xylose lysine deoxycholate (XLD) agar was used for plating out and identification purpose. A loop-full of inoculums from the RV broth and MKTT was streaked onto the surface of xylose lysine deoxycholate agar prepared in two separate Petri dishes. The plates were incubated at 37\u0026deg;C for 24 hours. After proper incubation, the plates were examined for the presence of suspected Salmonella colonies, which appeared pink with a darker pink center on XLD agar (ISO, 2002).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConfirmation\u003c/strong\u003e \u003cp\u003eSuspicious colonies were further sub cultured in nutrient media for biochemical tests.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eBiochemical tests\u003c/b\u003e: All suspected non-lactose fermenting Salmonella colonies were picked from the nutrient agar and inoculated into the following biochemical tubes for identification: triple sugar iron (TSI) agar, Simmon\u0026#146;s citrate agar, urea broth, tryptone soya broth, MR-VP broth and then incubated for 24 to 48 hours at 37\u003csup\u003eo\u003c/sup\u003eC. Triple Sugar Iron Agar (TSIA), Urease, Citrate, Indole, Methyl red and Voges Proskauer (VP) tests were done. Colonies producing red slant (alkaline), with yellow butt (acid) on TSI with blackening (H\u003csub\u003e2\u003c/sub\u003eS- hydrogen sulphide production) and bubbles (gas production) in butt, negative for urea hydrolysis (yellow), positive for citrate utilization (deep blue slant), negative for tryptophan utilization (indole test) (yellow-brown ring), positive for Methyl red and negative for Voges-Proskauer (VP) test were considered to be salmonella positive (ISO 6579, 2002; Quinn \u003cem\u003eet al.\u003c/em\u003e, 2004). Isolate presumptive of salmonella for all biochemical tests were cultured on Nutrient Agar (NA) for antimicrobial susceptibility testing.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.7.2. Isolation and identification of \u003cem\u003eEscherichia coli\u003c/em\u003e\u003c/h2\u003e \u003cp\u003e \u003cb\u003eBacteriological culturing and examination\u003c/b\u003e: All samples were cultured on blood agar and incubated aerobically at 37\u0026deg;C for 24-48hrs. After colony morphological examination, type of hemolytic, and gram staining characteristics pure colonies were further sub cultured on nutrient and MacConkey agars for 24-48hrs at 37\u0026deg;C. The presence of growth on MacConkey agar was used as primary criteria to proceed for isolation and identification of \u003cem\u003eE. coli\u003c/em\u003e. Furthermore, the colony characteristics observed on MacConkey agar was used to classify suspected bacteria isolated into two groups: lactose fermenter and non-lactose fermenter. Suspected \u003cem\u003eE. coli\u003c/em\u003e colonies were presumptively identified their lactose fermenting character (pink colonies). Suspected \u003cem\u003eE. coli\u003c/em\u003e were further sub cultured in Eosin methyl blue (EMB) agar medium for further identification. The characteristic colonies on EMB were identified based on green metallic sheen or blue-black to brown color. All isolated colonies were preserved on nutrient agar for further biochemical tests.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003ePrimary identification of bacterial isolates\u003c/strong\u003e \u003cp\u003eAll isolates were checked for purity using gram staining technique and primary biochemical tests including Oxidase test, Catalase test and Oxidation-fermentation tests. Bacterial isolates that showed a positive result on Catalase tests, negative result on oxidation test and fermentative up on O-F test were presumed to be members of Enterobacteria and were used for further studies.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSecondary identification of bacterial isolates\u003c/strong\u003e \u003cp\u003eIsolated bacterial pathogens with specific cultural characteristics of \u003cem\u003eE. coli\u003c/em\u003e were maintained on nutrient agar, and subjected to biochemical tests such as Methyl red (MR), Vogues Proskauer (VP) test, Indole test, Citrate test, and Urease test (Marchant and Packer, 1967).\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e2.7.3. Isolation and identification of pathogenic \u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/h2\u003e \u003cp\u003e \u003cstrong\u003eBacteriological culturing and examination\u003c/strong\u003e \u003cp\u003eA loop full of fecal sample was streaked on 5% sheep blood agar and the plates were incubated aerobically at 37\u0026deg;C and examined after 24 hrs of incubation for growth. The colonies were provisionally identified on the basis of staining reaction with Gram's stain, cellular morphology and hemolytic pattern on blood agar.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003ePrimary and secondary identification of bacterial isolates\u003c/strong\u003e \u003cp\u003eThe culture colonies were sub cultured on nutrient agar and incubated at 37\u0026deg;C for 24 hrs for primary and secondary identification of \u003cem\u003eStaphylococcus aureus\u003c/em\u003e. The isolated colonies from nutrient agar were exposed to Catalase test,Citrate utilation test and Methyl-red test. Colonies were grown on manitol salt agar grow and produce yellow color colony and \u003cem\u003eS. aureus\u003c/em\u003e were isolated for anti-microbial susceptibility testing (Quinn \u003cem\u003eet al\u003c/em\u003e., 2004).\u003c/p\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e2.8. Antimicrobial Susceptibility Test\u003c/h2\u003e \u003cp\u003eThe antibiotic susceptibility tests of Salmonella species, \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eEscherichia coli\u003c/em\u003e isolates were performed according to the National Committee for Clinical Laboratory Standards (NCCLS) method using Kibry-Bauer disk diffusion test on Muller-Hinton agar (CLSI, 2014).\u003c/p\u003e \u003cp\u003ePure colonies from nutrient agar were taken with a wire loop and transferred to a tube containing 5 ml of Saline water, emulsified and the turbidity was compared with 0.5 McFarland turbidity standards. Sterile cotton swab was dipped into the suspension and the bacteria were swabbed uniformly over the surface of Muller- Hinton agar plate within a sterile bio-safety cabinet. The plates were held at room temperature for 15 minutes to allow drying. Antibiotic discs with known concentration of antimicrobials were placed at equal distance and the plates were incubated at 37\u0026deg;C for 24 hrs. Each isolate was tested for a series of nine different antimicrobials. Following incubation, the diameters of clear zones produced by antimicrobial inhibition of bacterial growth were measured and recorded to the nearest mm for each disc using transparent digital caliper and then classified as resistant, intermediate or susceptible/sensitive according to published interpretive chart of (CLSI, 2014).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e2.9. Data Management and Analysis\u003c/h2\u003e \u003cp\u003eData collected from both field and laboratory were recorded in the format developed for this purpose and later on entered into the Microsoft excel 2013 program and analyzed using STATA 13 software. It was summarized by descriptive statistics and then displayed by tables to illustrate the relationships between the dependent variables (Salmonella species, \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eEscherichia coli\u003c/em\u003e isolates) and their total and independent variables (age, sex, type of diarrhea, method/ awareness/ time of colostrum feeding, management/ production system and medication/vaccination). Association of host risk factors with culture positives isolates was calculated. Antibiotic efficacy was determined by comparing zone of inhibition of each drug with the standard.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. RESULTS","content":"\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Bacterial Isolation and Identification\u003c/h2\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e3.1.1. Frequency of isolation of \u003cem\u003eE. coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eFecal samples were examined for the presence of \u003cem\u003eE. coli, Staphylococcus aureus\u003c/em\u003e and Salmonella species using standard bacteriological techniques. The present finding indicated that \u003cem\u003eE-coli\u003c/em\u003e was detected in 19(50%) where as Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e were detected in 12(31.6%) and 7(18.4%) respectively from the total samples of diarrheic calves examined, as summarized in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e \u003ch2\u003e3.1.2. Association of \u003cem\u003eE. coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e with different risk factors\u003c/h2\u003e \u003cp\u003eDuring the present study association among the factors with the isolates was done as shown in Table \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Seventy five percent of \u003cem\u003eE. coli\u003c/em\u003e were isolated from the age group of 9 up to 12 months where as 40% of Salmonella species isolates were found from age group of 6\u0026ndash;9 months and 23.5% of \u003cem\u003eStaphylococcus aureus\u003c/em\u003e were isolated from age group of 3\u0026ndash;6 months. Most of the isolates of \u003cem\u003eE. coli\u003c/em\u003e (37.8%), Salmonella species (29.7%) were found from female calves whereas 15.4% of isolates \u003cem\u003eStaphylococcus aureus\u003c/em\u003e were found from male calves.\u003c/p\u003e \u003cp\u003eMajority of the calf owner have the awareness on the importance of colostrum feeding. Most of the \u003cem\u003eE. coli\u003c/em\u003e (54.6%) and Salmonella species (27.8%) isolates were found from the dairy calves whose owners don\u0026#146;t have awareness about colostrum feeding. Hand feeding was the most common method of colostrum feeding and most of the owners feed their calves within the first 6 hours after birth. About 16.7% \u003cem\u003eStaphylococcus aureus\u003c/em\u003e was isolated from hand fed calves. However, 42% of \u003cem\u003eE. coli\u003c/em\u003e, 28.6% salmonella species were isolated from calves that suckle directly from their dam.\u003c/p\u003e \u003cp\u003eOn the basis of time of colostrum feeding, \u003cem\u003eE. coli\u003c/em\u003e (45.5%), Salmonella (27.8%) were found on those calves that took colostrum after 6 hours of birth. Regarding the treatment, 50% of \u003cem\u003eE. coli\u003c/em\u003e, 25% Salmonella and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e were isolated from those calves who didn\u0026#146;t take any treatment within the study period. Similarly, relatively higher \u003cem\u003eE. coli\u003c/em\u003e (50%), Salmonella (25%) and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e (14.3%) isolates were found from semi-intensive production system. Related to the type of diarrhea, 43.8% of \u003cem\u003eE. coli\u003c/em\u003e were isolated from watery diarrhea, 28.6% of Salmonella species were isolated from bloody diarrhea and 21.4% of \u003cem\u003eStaphylococcus aureus\u003c/em\u003e were isolated from mixed diarrhea.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe proportion of bacterial isolates with different risk factors\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003eIsolated Bacterial Species\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVaribles\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eE.coli\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eSalmonella spp.\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCategories\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eAge(months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;3 month\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3(30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1(10)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(3\u0026ndash;6]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(29.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(17.67)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4(23.53)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(6\u0026ndash;9]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(33.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(13.33)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(9\u0026ndash;12]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0(0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14(37.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11(29.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5(13.51)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(38.46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(7.69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(15.38)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDistrict\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMekelle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8(38.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(33.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(9.52)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWukro\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11(37.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5(17.24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5(17.24)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAwareness of colostrum feeding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13(33.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9(23.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7(14)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(54.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(27.27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0(0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMethod of colostrum feeding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSuckling\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(42.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4(28.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1(7.14)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHand feeding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13(36.11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8(22.22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6(16.67)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eColostrum feeding time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBefore 6 hrs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9(32.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(21.43)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6(21.43)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAfter 6 hrs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10(45.45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(27.27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1(4.55)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTreatment status\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTreated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7(26.92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(23.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1(3.85)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNon-treated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12(50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6(25)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eProduction system\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIntensive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(22.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5(22.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3(13.64)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSemi-intensive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14(50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4(14.29)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eType of Diarrhea\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWatery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7(43.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(18.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(12.50)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBloody\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3(42.86)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(28.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0(0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMucoid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4(30.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(23.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(15.38)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMixed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(35.71)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4(28.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3(21.43)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e3.1.3. Biochemical profile of the bacterial isolates\u003c/h2\u003e \u003cp\u003eAs indicated in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, on the basis of colony characteistics, all \u003cem\u003eE.coli\u003c/em\u003e isolates were lactose fermenter on Macconkey agar, dark green metallic sheen colony on EMB agar and pink colored colony on Salmonella shigella agar whereas Salmonella species isolates were colorless on Macconkey and shamonella shigella agar and doesn\u0026#146;t grow on EMB agar. All \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were grown on Mannitol salt agar with yellow colony.\u003c/p\u003e \u003cp\u003eOn the basis of biochemical tests, Both Salmonella species and \u003cem\u003eE.coli\u003c/em\u003e isolates were postive for methyl red test and motile on SIM media whereas they were negative on citrate utilization test. Further more, hydrogen sulphide production was observed only by the isolated salmonella species. All \u003cem\u003eE.coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were catalase and Methyl red positive. \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were β-hemolytic on blood agar, fermentative on O-F basal media and utilized sodium citrate on citrate utilization test.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eGram reaction, Colony and Biochemical characterstics of the isolated bacteria\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eCharacteristics of the isolated bacteria\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eE.coli (19)\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSalmonella spp. (12)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS. \u003cem\u003eaureus\u003c/em\u003e (7)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eColony characteristics\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMacconkey agar\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLactose fermenter (Pink)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eColorless\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo growth\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEMB agar\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMethalic sheen colony\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo growth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo growth\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSalmonella shigella agar\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePink colour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eColourless\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo growth\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eManitol salt agar\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo Growth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo Growth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYellow\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemolytic character\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHemolytic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eβ-Hemolytic\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGram reaction\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBiochemical tests\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCatalase test\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMotility:\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eO-F test:\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFermentative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNon- Fermentative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFermentative\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eS production\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndole test\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCitrate utilization test\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMethyl red test\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePostive\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Antimicrobial Susceptibility Test\u003c/h2\u003e \u003cp\u003eAntimicrobial susceptibility testing was performed for all of the bacteria isolated from the diarrheic calves and the result was as presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e below.\u003c/p\u003e \u003cp\u003eMost of \u003cem\u003eE.coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were sensitive to Streptomycin, Polymyxin-B and Gentamycin. However, most of \u003cem\u003eE.coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were resistant to Clindamycin, Kanamycin and Methicillin. Detail antimicrobial susceptibility profiles of the isolated bacteria against the tested antibiotics is indicated in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAntimicrobial susceptibility pattern of \u003cem\u003eE. coli, Salmonella spp and Stapylococcus aureus\u003c/em\u003e isolated from diarheic calves\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eAntimicrobial discs\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"9\" nameend=\"c10\" namest=\"c2\"\u003e \u003cp\u003eSpecies of bacteria\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e\u003cem\u003eE. coli\u003c/em\u003e (N\u0026thinsp;=\u0026thinsp;19)\u003c/p\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003e\u003cem\u003eSalmonella spp.\u003c/em\u003e (N\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003e\u003cem\u003eStaphylococcus aureus\u003c/em\u003e (N\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePencillin G\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5 (26.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4(21.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10(52.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e8(66.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e4(57.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSteptomycin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10(52.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5(26.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4(21.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(58.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5(71.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClindamycine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4(21.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6(31.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e9(47.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5(41.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e4(57.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKanamycin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7(36.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2(10.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10(52.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6(50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e4(57.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVancomycin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e9(47.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7(36.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3(15.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7(53.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e3(42.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePolymyxin-B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14(73.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2(10.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3(15.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(58.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3(25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5(71.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGentamycin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15(78.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2(10.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2(10.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8(66.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e4(57.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eErythromycin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3(15.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7(36.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e9(47.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5(41.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5(71.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMethicillin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4(21.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7(36.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8(42.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e2(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e3(42.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eN- Number, S-Susceptible, I-Intermediate and R-Resistance\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. DISCUSSION","content":"\u003cp\u003eIn the current study, an attempt has been made to isolate and identify \u003cem\u003eE. coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e from calves suffering from diarrhea, to identify the associated risk factors and also to determine the antibacterial susceptibility patterns of those isolated \u003cem\u003eE. coli\u003c/em\u003e in selected dairy farms located in Mekelle and Wukro. Various study findings revealed that calf diarrhea is major health problems in dairy farms via causing high mortality and morbidity of calves. In addition, calf diarrhea has played a great economic loss like money spent on treatment costs, loss of genetic potential both from the loss of calves and reluctance of farmer to invest in higher price semen in the face of calf mortality problem, also impair appropriate heifer replacement (Svenson \u003cem\u003eet al\u003c/em\u003e., 2003) and this influence the ability of dairy men to increase production by allowing them to practice selective culling of low productive cows.\u003c/p\u003e \u003cp\u003eOut of 50 faecal samples, 38 bacteria were isolated and 19(50%) were postive for \u003cem\u003eE.coli\u003c/em\u003e giving lactose fermentation on MacConkey agar plate, methalic green sheen colonies on EMB plates and pink color colony on Salmonella Shigela agar plate whereas 12(31.6%) samples were found postive for Salmonella species, giving negative reaction to lactose fermentation on MacConkey agar plate and Salmonella species produce translucent and colorless colonie on s Salmonella Shigela agar plate. 7(18%) samples were postive for stoaphlococcous producing yellowish colonies on Manitol salt agar and beta hemolysis on Blood agar. Differences in colony morphology manifested by the isolates may be due to to loosing or acquiring some roperties by the transfer of host or choice of host tissue as observed by Dubreuil et. al (1991).\u003c/p\u003e \u003cp\u003eThe isolated \u003cem\u003eE. Coli, Staphylococcus aureus\u003c/em\u003e and Salmonella species showed identical result in different biochemical test including sugar fermention, Indole test, H\u003csub\u003e2\u003c/sub\u003eS production test, Citrate utilization test, Motility and methyl-red test. It is reported that more than one predisposing factor such as environmental and managment factors (housing, climate) inbalance nutrition, immune status of the calves might help in the production of calf diarrhea along with the presence of one or more than one type of bacteria (Fouquet, 1979 and Debnath \u003cem\u003eet al.\u003c/em\u003e, 1987).\u003c/p\u003e \u003cp\u003eThe result of frequency distribustion of bacterial isolates are presented Out of 50 faecal samples, 19 (50% ) Sample were postive for E. Coli, 12 (31.6%) samples were postive for Salmonella spp., 7 (18.4%) postive for satphylococcus spp., were found in the fecal calf diarrhea. Result of present study indicated that all the three different type of bacteria were present in the faecal sample collected from diarrheac calves. The incidence of different type of bacteria isolated from calve diarrhea, correlated with the finding of Raseswari shomel et al. (1996). Haque samad ( 1996) isolated 9.61% Salmonella from calves, Joon and Kaura (1993) isolated 23 (23%) E.coli and 5 (5%) Salmenella from 100 facecal samples. This variation in the occurrence of the bacterial isolates could come from the difference in climatic conditions, sample size, variations in age groups examined (sample collected), feeding managements, environment condition, and poor hygiene often allows buildup of pathogenic strains in young animal\u0026#146;s environment.\u003c/p\u003e \u003cp\u003eIn the present study, an attempt has been made to isolate and identify \u003cem\u003eE. coli\u003c/em\u003e Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e associated with calf diarrhea, as well as investigation of the potential risk factors, which could influence the occurrence of calf diarrhea. In addition, determination of antimicrobial susceptibility of the bacterial isolates was conducted.\u003c/p\u003e \u003cp\u003eThe research was comducted to isolate, identfy and characterised the bacterial pathogens causing calf diarrhea in Mekelle city and Wukro town Tigray, Ethiopia. A total sample 50 faecal samples were collected and examined bacteriologicaly for the isolation, iydentificatin, frequency distribustion, and antimicrobial susceptibility test for the isolated pathogenic bacteria from calve diarrhea. the result of isolation and iydentrificationof E. Coli, salmonella spp and stapyloccus spp. The patogenic bacteria charactrised using by Gram staining, cultural bioichemical test.\u003c/p\u003e \u003cp\u003eOut of 50 faecal samples 19 were postive for E.coli giving lactose fermentation on MacConkey agar plate,methalic green sheen colonies on EMB plates and pink color colony on salmonella shigela agar plate. 12 samples were found postive foe salmonella spp,giving negative reaction to lactose fermentation on MacConkey agar plate.and salmonella spp produce translucent and colorless colonie on s-s agar plate. 7 samples were postive for stoaphlococcous producing yellowish colonies on Manitol salt agar and hemolysis on Blood agar.Differences in colony morphology manifested by the isolates may be due to to loosing or acquiring som properties by the trans fer of host or choice of host tissue as observed by Dubreuil et al. (1991).\u003c/p\u003e \u003cp\u003eThe isolated E. Coli, Staphylococcus and Salmonella showed iydentical result in different biochemical test including sugar fermention, Indole test,H\u003csub\u003e2\u003c/sub\u003eS production test,Citrate utilization test, Motility and methyl-red test. It is reported that more than one predisposing factor such as environmental and managment factors (housing, climate) inbalance nutrition, immune status of the calves might help in the production of calve diarrhea along w ith the presence of one or more than one type of bacteria ( Fouquet,1979 and Debnath et,.1987).\u003c/p\u003e \u003cp\u003eThe result of frequency distribustion of bacterial isolates are presented Out of 50 faecal samples, 22 (44% ) Sample were postive for E. Coli, 14 (28%) samples were postive for Salmonella spp., 8 (16%) postive for satphylococcus spp., 9 ( 18%) samples were mixed infection and 6 (12%) samples were negative for bacteria.\u003c/p\u003e \u003cp\u003eThe frequency distribustion of different species of bacterial isolates in different faecal samples were found variable. Result of present study indicated that all the three different type of bacteria were not present in same faecal sample collected from diarrheac calves. The incidence of different type of bacteria isolated from calve diarrhea, correlated with the finding of Raseswari shomel et al. (1996). Haque samad ( 1996) isolated 9.61% Salmonella from calves, Joon and Kaura (1993) isolated 23 (23%) E.coli and 5 (5%) Salmenella from 100 facecal samples.\u003c/p\u003e \u003cp\u003eThe isolated pathogenic bacteria isoalated from calf diarrhea E.coli, salmenella spp, and staphylococcus spp, were correlated with finding of Abdullah et al.,(21013). Atotal 114 faecal samples was collected from diarrhic calf diarrhea out of thsese, 44 (38.6%) samples were postive for E.coli, 25 (21.9%) samples were postive for Salmonella spp., 15 (13.2%) samples were postive for \u003cem\u003eStaphylococcus aureus\u003c/em\u003e, 18 (15.8%) samples wre mixed infection and 12 (10.5%) samples were negative for bacteria.\u003c/p\u003e"},{"header":"5. CONCLUSION AND RECOMMENDATIONS","content":"\u003cp\u003eOut of the 50 fecal samples colected from diarheic calves, 76% were found harboring one or more GI bacteria at varying levels. \u003cem\u003eE.coli\u003c/em\u003e, Salmonella species and \u003cem\u003eS.aureus\u003c/em\u003e were isolated at a rate of 50%, 31.6% and 18.4% repectively from the diarheic dairy calves in the study districts. It was found that age, method of colostrum feeding, colostrum feeding time and production system were associated with higher bacterial isolation and occurrence of calf diarrhea. Accordingly, higher bacterial species were isolated from 6\u0026ndash;9 months old calves mnaged in semiextensive production system which consumed colostrum after 6 hrs of birth. Majority of the dairy farm owners have awarenes on the importance of colostrum feeding. The antibiogram conducted in the current work has shown an increased level of resistance among the isolated bacteria against the commonly used antibiotic drugs. Most of \u003cem\u003eE.coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were sensitive to Streptomycin, Polymyxin-B and Gentamycin.\u003c/p\u003e \u003cp\u003eTherefore, based on the above concluding remarks the following points are recommended:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eThe extension works to improve care to calves and ensuring ingestion of adequate colostrum as early as 24 hour of life is the best way of giving calves a good start to life and is crucial to reduce calf diarrhea.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFurther characterization and potential effect of the isolated bacteria on the health and productivity of the calf needs to be studied further.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eDiarrhea in calves is caused by the synergistic effect of predisposing factors. Hence, further studies should be carried out to look in the role of viruses, parasites, fungi and anaerobic bacteria as primary or secondary causes of calf diarrhea.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIn consideration of the most effective \u003cem\u003ein-vitro\u003c/em\u003e antibacterial agents against the isolated bacteria, Streptomycin, Polymyxin-B and Gentamycin should be the drugs of choice in controlling diarrhea in calves.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAnimal Ethics Statement for Preprint\u003c/p\u003e\n\u003cp\u003eEthical clearance was obtained prior to conducting the study from the Mekelle University, College of Veterinary Sciences Research Ethics Review Committee (RE: Notification of Protocol Approval No. MU-IRB2156/2024). All animal handling and experimental procedures were carried out in accordance with accepted ethical guidelines for the care and use of animals. Efforts were made to ensure animal welfare and to minimize stress, discomfort, and suffering throughout the study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eCLSI. (2014): Performance standards for antimicrobial susceptibility testing. CLSI document M100-S24. Wayne, PA: Clinical and Laboratory Standards Institute; 65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQuinn, P. J., Carter, M. E., Markey, B. and Carter, R. G. (2005): Clinical Veterinary Microbiology, 7th edition, (Elsevier Health Science Ltd., Philadelphia).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQuinn, P. J., Markey, B. K., Carter, M. E., Donnelly, W. J. and Leonard, F. C. (2002): Veterinary Microbiology and Microbial Disease, Black well Science, pp 137\u0026ndash;143.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eISO 6579 (2002). Microbiology of food and animal feeding stuff: horizontal method for the detection of \u003cem\u003eSalmonella spp\u003c/em\u003e. Geneva, 511\u0026ndash;525.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThorns, C., Bell, M., Chasey, D., Chesham, J. and Roeder, P. (1992). Development of monoclonal antibody ELISA for simultaneous detection of bovine coronavirus, rotavirus serogroup A, and \u003cem\u003eEscherichia coli\u003c/em\u003e K99 antigen in feces of calves. \u003cem\u003eAm. Vet. Res.\u003c/em\u003e, \u003cb\u003e53\u003c/b\u003e:36\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHu, X., Li, L., Cao, Y., Zhang, J., Gong, M. and Yang F. (2010). \u0026#147;Isolation and identification of a phosphate-solubilizing bacterium Pantoea stewartii subsp. stewartii g6, and effects of temperature, salinity, and pH on its growth under indoor culture conditions.\u0026#148; \u003cem\u003eAqua. Inter\u003c/em\u003e., \u003cb\u003e18\u003c/b\u003e(6): 1079\u0026#150;1091.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMerchant, I. and Packer, R. (1967). Veterinary Bacteriology and Virology 6th Ed., Iowa State University Press USA, 128\u0026ndash;133.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElham, I., Atwa-Eman, M., Sharaf, and Eman, M. (2012).Bacterial Diarrhoea in Newly Born Calves in Menoufiea Governorate. \u003cem\u003eAssiut Vet. Med.\u003c/em\u003e, \u003cb\u003e58\u003c/b\u003e: 135.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAiello, S. E, May, A. (1998): The Merck Veterinary Manual. 8th edition. New Jersey. USA: Merck and Co, Inc, Pp. 1053\u0026ndash;1057.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLobago, F. B. Bekana, H. Gustafsson and H. Kindahl, (2006): Reproductive performance of dairy cows in small holder production system in selalle, Central Ethiopia. \u003cem\u003eTrop. Anim. Prod. Health\u003c/em\u003e, \u003cb\u003e38\u003c/b\u003e: 333\u0026ndash;342.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCentral Statistical Agency, (2009): The Federal democratic republic of Ethiopia Central Statistical Agency, agriculture in figure key findings of the 2008/09-2010/11 agricultural sample surveys for all sectors and seasons Country Summary, FDRECSA Addis Ababa, Ethiopia, Pp.: 14\u0026ndash;18.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbdisa B. and Minda A. (2016). Major Calf Health Problems and Exposing Risk Factors at Holeta Agricultural Research Center Dairy Farm, Holeta, Ethiopia. \u003cem\u003eJournal of Global Veterinaria\u003c/em\u003e, 17 (1): 05\u0026ndash;14.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAch\u0026aacute;, S., K\u0026uuml;hn, I., Jonsson, P., Mbazima, G., Katouli M. and M\u0026ouml;llby R. (2004): Studies on Calf Diarrhoea in Mozambique: Prevalence of Bacterial Pathogens Acta Vet. Scand. \u003cb\u003e45\u003c/b\u003e(1): 27\u0026#150;36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmaha, K. (2002): An Integrated Urban, Peri- Urban and Rural Dairy Development Program in Tigray .Diary animal health project (Final Report).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAsefa A., Asmare W. and Ashenafi K.(2016). Dairy calf morbidity and mortality and associated risk factors in Sodo town and its suburbs, Wolaita zone, Ethiopia. \u003cem\u003eSlovak Journal Animal Science\u003c/em\u003e, \u003cspan type=\"BoldItalic\" class=\"BoldItalic\" name=\"Emphasis\"\u003e49\u003c/span\u003e \u003cem\u003e(1): 44\u0026#150;56.\u003c/em\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBazeley, K. (2003). Investigation of diarrhea in the neonatal calf. In practice, 25: 152\u0026ndash;159.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBOANR (1997): Tigray Livestock development action program main report, Vol.1. bureu of Agriculture and Natural Resourses, Mekkelle, Tigray .Pp. 1\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChoY. And Yoon K. (2014). An overview of calf diarrhea-infectious etiology, diagnosis, and intervention. Journal of Veterinary Science, \u003cb\u003e15\u003c/b\u003e (1):1\u0026#150;17.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eClinical and laboratory standards institute (2006). Performance standareds for antimicrobial disk susceptibility testing. 16th informational supplement. M100-S16. Wayne, Pa.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCSA (Central Statistics Authority), 20010/11. \u003cem\u003eAgricultural sample survey 2010/2011.\u003c/em\u003e Vol. II.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCSA.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDACA, (2006): Standared veterinary treatment guide lines for vet.Practice 1st ed DACA. Addis Ababa, Ethiopia. Efficiency of Boss indicus (Zebu) cows under artificial insemination. Amin. Report. Sci. 24:63\u0026ndash;72\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElham I., Atwa. Eman M., Sharaf and Eman M. (2012). Bacterial Diarrhoea in Newly Born Calves in Menoufiea Governorate. \u003cem\u003eJournal of Assiut Veterinary Medicine\u003c/em\u003e, \u003cb\u003e58\u003c/b\u003e: 135.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHalderman, M.N. 2004. \u003cem\u003eThe political economy of pro-poor livestock policy making in Ethiopia\u003c/em\u003e. FAO working paper No. 19. Rome: FAO.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHemashenpagan N; B. Kiruthiga; T. Selvaraj and A. Panneerselvam, (2007). Isolation, Iydentification and Characterization of Bacterial pathogens causing Calf diarrhea with special reference to Escherichia coli. The intrnat journal of Microbiology, 7(2), DOI: 10.5580/9c7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eILCA, (1998): Animal reproduction for for African counties, Report of ajoint ajiont seminar bi internationl foundation for science and Swedish international program on animal production. ILCA, Addis Ababa, Ethiopia.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLemma,M, Kasha T, Azage T(2001) Clinically manifesed major health problems of cross breed dairy breeds in urban and peri-urban production systems in central highlands of Ethiopia TROP Animal health Prod 33(2):85\u0026ndash;93\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOIE (Office International Des Epizooties ) (200).Manual of standards for diagnostics test and vaccine. OIE Guide \u0026minus;\u0026thinsp;2.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOFED(Office of Finance and Economic Development), 2008. Socio-economic statistical abstract, Wukro,Tigray.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrescott B., Kee M., Glock R., Cuneo P., Young D., Reggiardo C., Trinh H., and Songer J. (2008): A possible role for Clostridium difficile in the etiology of calf enteritis. \u003cem\u003eJournal of Veterinary Microbiology\u003c/em\u003e, \u003cb\u003e127\u003c/b\u003e(3\u0026ndash;4): 343\u0026ndash;352.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRadostits, O,M; D.C. Blood and G.c. Gay (2000). Veterinary Medicine : Atext Book of the Disease of Cattle, Sheep, Pig, Goat and Horse. 8th Edn.W.B. Saunders Company, philadelphia, London.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReport on livestock and livestock characteristics. Statistical Bulletin. Addis Ababa, Ethiopia:\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Mekelle University","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Antibiotic susceptibility, diarrheic dairy calf, Escherichia coli, Mekelle, Salmonella species, Staphylococcus aureus, Wukro","lastPublishedDoi":"10.21203/rs.3.rs-8512251/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8512251/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA cross-sectional study was carried out from October, 2024 to February, 2025 in Mekelle and Wukro districts with the objective of isolation and determination of the antimicrobial susceptibility profile of Salmonella species, \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eEscherichia coli\u003c/em\u003e isolated from clinically diarrheic dairy calves. A total of 50 faecal samples were collected directly from the rectum of diarrheic calves and brought to the Microbiology laboratory of Mekelle University, College of Veterinary Medicine, for bacteriological examination. Isolation and identification of the microorganisms were done on the basis of their colony and cellular morphology, staining, and primary and secondary biochemical tests targeted for each pathogen. Furthermore, the antimicrobial susceptibility profile of the isolated bacteria were carried out using disc diffusion method. Only 38 of the total 50 faecal samples, yield Salmonella species, \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and \u003cem\u003eEscherichia coli.\u003c/em\u003e Out of the total 38 fecal samples, 19 (50%) samples were positive for \u003cem\u003eE. coli\u003c/em\u003e, 12 (31.6%) samples were positive for \u003cem\u003eSalmonella species and\u003c/em\u003e 7 (18.4%) samples were positive for \u003cem\u003eStaphylococcus aureus.\u003c/em\u003e The antibiogram study revealed that most of \u003cem\u003eE.coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were sensitive to Streptomycin, Polymyxin-B and Gentamycin. However, most of \u003cem\u003eE.coli\u003c/em\u003e, Salmonella species and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were resistant to Clindamycin, Kanamycin and Methicillin. Most \u003cem\u003eStaphylococcus aureus\u003c/em\u003e isolates were susceptible to penicillin, erthromycin and clindamycin whereas resistant was developed against penicillin, erthromycin and clindamycin by most isolates of \u003cem\u003eE.coli\u003c/em\u003e and Salmonella species. In conclusion, \u003cem\u003eE.coli\u003c/em\u003e and Salmonella were the bacterial species frequently isolated from diarrheic dairy calves in the study area. The results of this study indicated that the isolates were susceptible to limited antimicrobial agents. Most isolates were found susceptible to Streptomycin, Polymyxin-B and Gentamycin. Further characterization and potential effect of the isolated bacteria on the health and productivity of the calf needs to be studied further.\u003c/p\u003e","manuscriptTitle":"Isolation and Antimicrobial Sensitvity pattern of Salmonella species, Staphylococcus aureus and Escherichia coli from diarrheic dairy calves in selected dairy Farms of Mekelle and Wukro, Tigray, Northern Ethiopia.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-09 08:17:36","doi":"10.21203/rs.3.rs-8512251/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2b5fde99-97cc-47b5-985c-2817be6ece81","owner":[],"postedDate":"January 9th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":60862467,"name":"General Microbiology"}],"tags":[],"updatedAt":"2026-01-09T08:17:37+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-09 08:17:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8512251","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8512251","identity":"rs-8512251","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}