Unmasking rifampicin mono-resistance in tuberculosis patients in Cross River State, Nigeria

Unmasking rifampicin mono-resistance in tuberculosis patients in Cross River State, Nigeria | 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 Unmasking rifampicin mono-resistance in tuberculosis patients in Cross River State, Nigeria Ernest Afu Ochang, Ubong Aniefiok Udoh, Akaninyene Asuquo Otu, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5424699/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 Sep, 2025 Read the published version in Discover Public Health → Version 1 posted 9 You are reading this latest preprint version Abstract Background Current tuberculosis management algorithm in Nigeria recommends commencement of multi-drug resistant tuberculosis (MDR-TB) treatment on rifampicin resistance detection, following XpertMTB/Rif (Genexpert) test and subsequent re-direction of therapy after phenotypic drug susceptibility testing. With the current dearth of phenotypic drug susceptibility testing facilities in Nigeria, for quick and precise identification of drug resistant tuberculosis, several rifampicin mono-resistant tuberculosis patients may be inappropriately placed on toxic second line drugs used for MDR-TB treatment for prolonged periods before susceptibility results are available. Method XpertMTB/Rif were performed on a total of 3,580 patient samples from 10 sites across Cross River State, Nigeria as a prospective cross sectional study. Rifampicin resistant specimens were reprocessed and cultured on Lowenstein Jensen medium. Indirect susceptibility testing following the microscopic observation drug susceptibility technique was performed using Rifampicin (1 µg/ml), Isoniazid (0.4 µg/ml), Flouroquinolone (Ofloxacin-1.0 µg), Capreomycin (2.5 µg/ml), Amikacin (2 µg/ml) and Kanamycin (5.0 µg/ml). Result Mycobacterium tuberculosis was detected in 21.3% (763) of the 3,580 presumptive tuberculosis cases recruited, of which 4.6% (35/763) were resistant to rifampicin. Culture yielded isolates from 89.6% (31/35) of these rifampicin resistant cases while susceptibility testing using first and second line antimicrobials, revealed 32.2% (10/31) and 64.5% (20/31) rifampicin mono-resistant and MDR-TB respectively. When categorized into treatment groups, 25.7% (27/105) and 1.2% (8/658) of patients with rifampicin resistance belonged to retreatment and naïve patient groups respectively. There was no correlation between rifampicin mono-resistant and MDR-TB with gender (χ2 = 0.793, P = 0.308) or HIV status (χ2 = 0.416, P = 0.398). Patients who presented with first line treatment failure were most likely to have MDR-TB (χ2 = 9.121, P = 0.028). Conclusion With the current MDR-TB treatment algorithm and lack of programmatic support for drug susceptibility testing, a significant number of patients with rifampicin mono-resistance are treated as MDR-TB for prolonged periods. More programmatic support and scale up of simpler susceptibility techniques are required. XpertMTB/Rif Genexpert MDR-TB DR-TB Drug Susceptibility Testing Mycobacterium tuberculosis Figures Figure 1 Introduction About 2 billion people (one quarter of the world’s population) are infected with Mycobacterium tuberculosis , the causative organism for tuberculosis which has accounted for about 1.3 million deaths( WHO 2023) [ 1 , 2 ]. Currently, Nigeria has a tuberculosis incidence of 361,000 with an incidence rate of 219/100,000 amongst a population of 191 million [ 2 , 3 ]. The emergence and spread of strains resistant to anti-tuberculosis chemotherapy has grossly undermined global control efforts [ 4 ]. Several strains resistant to rifampicin and isoniazid, described as multi-drug resistant tuberculosis (MDR-TB) and some MDR-TB also resistant to aminoglycosides and quinolones described as extensively drug resistant tuberculosis (XDR-TB) have continued to spread across the world [ 5 – 8 ]. Recently, totally drug resistant tuberculosis (TDR-TB) strains have also emerged [ 9 , 10 , 11 ]. MDR/RRTB incidence rate in Nigeria is estimated at 12/100,000 population with the proportion of MDR/RRTB patients estimated to have MDR-TB put at 66% [ 2 , 12 ]. Following the endorsement of XpertMTB/Rif (Cepheid Inc. CA USA) popularly referred to as Genexpert by the WHO for prompt detection of tuberculosis, it was deployed into the Nigerian National Tuberculosis Programme in 2015 [ 13 ]. This real time multiplex polymerase chain reaction technology rapidly detects organisms of the Mycobacterium tuberculosis complex and rifampicin resistance [ 14 , 15 , 16 ]. It has significantly improved tuberculosis diagnosis in the country [ 17 , 18 , 19 , 20 ]. The operational algorithm for XpertMTB/Rif used in Nigeria recommends commencement of MDR-TB treatment on rifampicin resistance detection and subsequent re-direction of therapy after phenotypic drug susceptibility testing (DST) [ 3 , 14 ]. The WHO in 2016, published guidelines for MDR-TB care of 20 months duration but suggested a possible short course of 12 months for rifampicin mono-resistant patients [ 21 ]. This can only be implemented with increased access to DST. Most DST facilities in the country are however still not functional and all specimens are shipped to the National reference laboratory in Zaria, Kaduna State [ 22 ]. With the current dearth of phenotypic DST facilities in Nigeria for the quick delineation of DR-TB cases, several rifampicin mono-resistant TB patients may be inappropriately placed on toxic second line drugs used for MDR-TB treatment for prolonged periods before DST results are available [ 23 ]. We decided to determine the proportion of non MDR-TB patients enrolled for treatment following rifampicin resistance detection with XpertMTB/Rif in Cross River State and possibly document evidence for the concomitant deployment of cheaper, safer alternative Mycobacterium tuberculosis culture methods in National programmes across resource limited settings. Materials and methods Study setting/subjects selection This study was coordinated from the Department of Medical Microbiology and Parasitology, University of Calabar Teaching Hospital (UCTH) Calabar, Cross River State, Nigeria from June 2015 to July 2016. Patients presenting with presumptive diagnosis of tuberculosis (patients with ≥ 2 of cough ≥ 2 weeks, fever, excessive night sweats, weight loss and history of contact with a patient with tuberculosis) [ 19 ] at 10 facilities across the State, with capacity for smear microscopy and genexpert were enrolled. Paediatric patients (patients < 16 years of age) with a National TB and Leprosy Control Programme (NTBLCP)/WHO risk score ≥ 7 and those with score ≤ 7 but unresponsive to high dose broad spectrum antibiotics [ 19 ] were also included. Patients who had already commenced anti-tuberculosis medication were excluded since they could be excreting dead (non-cultivable) bacilli. Written informed consent was obtained from all participants. Where the participants were under 18, written informed consent was obtained from a parent and/or legal guardian. Ethical consideration Ethics approval was obtained from the University of Calabar Teaching Hospital (UCTH) Health Research Ethics Committee (UCTH/HREC/33/259) and the Cross River State Human Research Ethics Committee (CRS/MH/CGS/E-H/018/Vol.II/119). The research was carried out following the guidelines of the ethics committees. Sample size The minimum sample size was calculated using the formula n = z 2 pq/d 2 , where: n = desired sample size (when population is greater than 10,000), z = the standard normal deviation which corresponds to 95% confidence level set at 1.96, p = proportion of target population, q = 1- p and d = desired degree of accuracy set at 0.05 [ 24 ]. A WHO incidence of 66% of MDR among MDR/RR-TB 2 was used to estimate a minimum sample size of tuberculosis positive cases of 344. A10% attrition was added to bring the minimum sample size of positive cases to 378. Specimen collection and processing Two sputum specimens were obtained by expectoration (one of which was an early morning specimen) from all adults and older children who could expectorate. Two early morning gastric aspirate were obtained from those less than 3 years of age who could not expectorate. In patients with suspected extra pulmonary tuberculosis, aspirates (lymph node, ascitic fluid, peritoneal fluid, pericardial fluid and cerebrospinal fluid) were collected according to the possible site of infection. Specimens were preserved at 2-8 o C until processed but not for longer than three days from the date of production. All processes were carried out by trained personnel. XpertMTB/Rif was performed as described in the standard operating procedure manual [ 13 ]. This was done by inoculating the XpertMTB/Rif cartridge with specimen, which was inserted into the machine within 30 minutes of inoculation. The XpertMTB/Rif machine would then automatically complete the gene extraction process and detect both Mycobacterium tuberculosis and the presence of mutations in the rpoB gene which codes for rifampicin resistance. Rifampicin resistant specimens were sent to UCTH Calabar and Dr. Lawrence Henshaw Memorial Hospital Calabar for LJ culture. Indirect MODS Phenotypic DST was then performed in the Mycobacteriology Research Laboratory, Department of Medical Microbiology and Parasitology, UCTH, Calabar. Due to a lack of equipment and capacity in other sites extra pulmonary specimens were evaluated in UCTH only. All LJ media were prepared in-house using standard protocol. Culture involved a decontamination step using the Sodium Hydroxide-Sodium Citrate-N-Acetyl Cysteine (NaOH-NALC) method. After centrifugation and discard of supernatant, the resulting pellet was inoculated on two LJ slants. MODS was carried out as described in the technique for preparation of positive controls in the MODS protocol manual [ 25 ]. Indirect MODS assay was chosen instead of direct MODS to avoid wastage that could have arisen from testing single samples as they arrived the laboratory, since the detection of Rifampicin resistance was infrequent. This was done by harvesting colonies of M. tuberculosis from LJ cultures (using sterile loops) into sterile tubes containing 100µl of water-tween-80 solution and six sterile glass beads. The tubes were vortexed for 2 minutes, allowed to stand for 5 minutes, then vortexed again for 20 seconds after adding 3ml of water-tween-80 solution and allowed to stand for another 30 minutes. The supernatant was transferred to another tube and its turbidity adjusted to 0.5 McFarland turbidity equivalent before culturing. During culture, 5µl of the 0.5 McFarland adjusted suspensions were added to 5ml of supplemented Middlebrook 7H9 broth. The preparations were cultured in 24-well tissue culture plates as described for processing positive controls in the MODS protocol. Two wells in each of 4 rows of the 24-well plate contained isoniazid and rifampicin at final diluted concentrations of 0.4µg/ml and 1µg/ml respectively. The plates were placed in ziploc bags and incubated at 37 ° C. A different plate was used for susceptibility testing of second line drugs with the following final concentrations; Flouroquinolones (Ofloxacin-1.0µg), Injectables (Capreomycin-2.5µg, Amikacin-2µg, and Kanamycin-5.0µg). Cultures were examined with an inverted microscope every alternate day from day 5 to 21. M. tuberculosis was identified by characteristic serpentine cord-like growth on inverted microscopy. Positive controls using previously LJ evaluated MDR and mono-resistant strains of M. tuberculosis were cultured after the specimens had been secured in the ziploc bags to prevent cross contamination. Culture media without samples were added to one row of wells in each plate as negative control. Specimens were regarded as positive if ≥ 2 colony forming units (CFU) were seen in the drug free wells and negative if none was seen. Wells with only 1CFU were regarded as indeterminate and the test repeated. Isolates were regarded as susceptible to any drug if no CFU was seen in the drug containing wells read on the same day as the drug free wells, and resistant if ≥ 2CFU were seen. Drug containing wells with 1CFU were regarded as indeterminate and the test repeated. Contaminated cultures were reprocessed. Data analysis All data was analyzed using the Statistical Package for Social Sciences (SPSS) software version 20.0. (SPSS Inc. Chicago, USA). Categorical data are presented as %(n) when data was available for all participants and as %(n/sample size) when data was only available for a subset of the study population. The χ 2 test was used to compare categorical data between groups. All p-values are two-sided and a p-value of < 0.05 was considered to be statistically significant. Results A total of 3,580 presumptive tuberculosis cases were recruited from 10 Genexpert sites in Cross River State, Nigeria. This included 53.1% (1904) females and 46.7% (1674) males with sex not indicated in 0.2% (8) of cases. Of the 98.9% (3541/3579) of patients whose ages were appropriately indicated, the mean age was 38.16 years and ranged from 10 months to 92 years. A total of 97.8% (3499) of specimens were sputum while 2.2% (80) were extra-pulmonary with pleural fluid, gastric aspirate, lymph node aspirate and ascitic fluid predominating (Table 1 ). It was observed that multiple re-testing at different sites with eventual multiple capture of patients into the national data was common. All multiple entries identified by similarity of names, sex and/or age were expunged from our data set. Table 1 Distribution of TB according to specimens Specimen type Genexpert Positive n (%) Ascitic fluid (n = 9) 0 (0) Lung tissue-Autopsy Specimen (n = 2) 2 (100.0) CSF(n = 4) 0 (0.0) Gastric Aspirate (n = 22) 1 (4.5) Knee Joint Aspirate(n = 1) 0 (0.0) Lumbar Aspirate (n = 1) 0 (0.0) Lymph node biopsy (n = 2) 0 (0.0) Lymph node aspirate (n = 11) 5 (45.5) Pleural Fluid (n = 27) 4 (14.8) Sputum (n = 3500) 751 (21.5) Tissue Biopsy (n = 1) 0 (0.0) Total TB Positive (n = 3580) 763 (21.3) Mycobacterium tuberculosis was detected in 21.3% (763) of the presumptive cases of which 4.6% (35/763) were rifampicin resistant. All rifampicin resistant specimens were from sputum samples. On LJ culture, growth was achieved from 89.6% (31/35) of specimens that were rifampicin resistant on genexpert. Using MODS first and second line, 32.2% (10/31) and 64.5% (20/31) were rifampicin mono-resistant and MDR respectively, while one XDR isolate was identified (Fig. 1). It was resistant to ofloxacin and the aminoglyosides (capreomycin, kanamycin, and amikacin). This was confirmed in the National TB reference laboratory Zaria and the patient enrolled on XDR-TB treatment. Figure 1. Flow diagram depicting steps in sample selection and specimen processing. When categorized into treatment groups, 25.7% (27/105) and 1.2% (8/658) of the rifampicin resistant patients belonged to retreatment and new patients respectively (Table 2 ). There was a cluster of TB and DR-TB between the ages of 21–50 years (Table 3 ). There was no correlation between rifampicin mono-resistance and MDR-TB with gender (χ2 = 0.793, P = 0.308) or HIV status (χ2 = 0.416, P = 0.398). Patients who presented with first line treatment failure were most likely to have MDR-TB (χ2 = 9.121, P = 0.028) Table 4 . Discussion Over 90% of resistance to rifampicin is attributable to mutations in the 81bp region of the rpoB gene known as the Rifampicin Resistant Determinant Region (RRDR) [ 14 , 26 ]. The Cepheid XpertMTB/Rif uses molecular beacons to probe five overlapping regions in the RRDR. These probes are represented as Probe A (507–511), Probe B (512–518), Probe C (518–523), Probe D (523–529) and Probe E (529–533) [ 26 ]. Rifampicin remains the most important drug in the management of tuberculosis and resistance to it, is assumed to suggest a possible resistance to other first line anti-TB drugs. With the advent of genexpert, it has become easier to detect rifampicin resistance in many resource poor settings. Unfortunately, there appears to be a mindset shift from providing required support for full drug susceptibility testing which should promptly re-define treatment. Table 2 Distribution of DR-TB according to patient treatment category TB Status Category Xpert Rifampicin Resistant n (%) MDR Rifampicin Mono-resistant n (%) Retreatment (n = 105) 27(25.7) 18(17.9) 6(5.7) New (n = 658) 8(1.2) 3(1.1) 4(0.6) Total (n = 763) 35(4.5) 21(2.7) 10(1.3) Table 3 Age related distribution of TB and DR-TB in genexpert tested presumptive TB patients. Age group TB Positive Genexpert Rif Resistant Rif Mono-Resistant MDR 0–5 (n = 44) 5(0.7) 0(0.0) 0(0.0) 0(0.0) 6–10(n = 98) 11(1.5) 0(0.0) 0(0.0) 0(0.0) 11–15(n = 131) 13(1.7) 0(0.0) 0(0.0) 0(0.0) 16–20(n = 164) 47(6.2) 2(5.7) 0(0.0) 1(4.8) 21–25(n = 335) 104(13.8) 1(2.8) 1(10.0) 0(0.0) 26–30(n = 421) 96(12.8) 4(11.4) 1(10.0) 3(14.2) 31–35(n = 537) 157(20.9) 8(22.9) 2(20.0) 5(23.8) 36–40(n = 359) 80(10.6) 10(28.6) 3(30.0) 6(28.5) 41–45(n = 396) 88(11.7) 4(11.4) 1(10.0) 2(9.5) 46–50(n = 255) 43(5.7) 3(8.6) 1(10.0) 2(9.5) 51–55(n = 247) 38(5.1) 1(2.8) 0(0.0) 1(4.8) 56–60(n = 198) 31(4.1) 0(0.0) 0(0.0) 0(0.0) 61–65(n = 122) 11(1.5) 1(2.8) 0(0.0) 1(4.8) 66–70(n = 87) 15(2.0) 1(2.8) 1(10.0) 0(0.0) 71–75(n = 88) 8(1.1) 0(0.0) 0(0.0) 0(0.0) 76–80(n = 26) 2(0.3) 0(0.0) 0(0.0) 0(0.0) 81–85(n = 19) 3(0.4) 0(0.0) 0(0.0) 0(0.0) 86–90(n = 2) 0(0.0) 0(0.0) 0(0.0) 0(0.0) 91–95(n = 2) 0(0.0) 0(0.0) 0(0.0) 0(0.0) Total 752(100) 35(100) 10(100) 21(100) Table 4 Correlates of Drug resistant tuberculosis Rif Mono-Resistant MDR χ2 df P HIV Status Positive(n = 16) 6 10 0.416 1 0.398 Negative(n = 15) 4 11 Total(n = 31) 10 21 Sex Female(n = 12) 5 7 0.793 1 0.308 Male(n = 19) 5 14 Total(n = 31) 10 21 Treatment Category New (n = 7) 4 3 Failure(n = 15) 2 13 9.121 3 0.028 RAD(n = 6) 4 2 Relapse(3) 0 3 Total(31) 10 21 In our study, 4.6% of all TB was rifampicin resistant, lower than a 12.1% resistance reported in Nasarawa State, Nigeria [ 27 ]. We also found a rifampicin mono-resistance of 32.2%., close to the 39.1% (45/115) prevalence detected in a Nigerian national survey conducted in 2012 using the Molecular Line Probe assay [ 28 ]. Kurbatova and colleagues on evaluating data from several supra-national tuberculosis reference laboratories across the world had noted a high proportion of rifampicin-resistant isoniazid-susceptible tuberculosis and issued caution on the universal application of MDR-TB treatment based on genexpert results [ 29 ]. In another retrospective evaluation of data from several centers globally, variations ranging from 14–45% directly proportional to the MDR-TB burden of the country were observed [ 30 ]. These authors also observed that rifampicin mono-resistant isolates were more likely to be susceptible to other second-line drugs than MDR strains. They re-enforced the need for isoniazid testing before commencement of MDR-TB treatment. The WHO global tuberculosis report 2018 also reported a 66% estimate of MDR among MDR/RR-TB patients [ 2 ]. The universal enrolment of patients with genexpert detected rifampicin resistance into MDR-TB treatment does not also consider patients with possible dormant rpoB genes. In India 4.6% of isolates initially diagnosed as resistant to rifampicin by XpertMTB/RIF, tested susceptible to rifampicin by phenotypic DST [ 26 ]. These strains of Mycobacterium tuberculosis although not encountered in our study, bear dormant rpoB mutations and demonstrate phenotypic and clinical rifampicin susceptibility. We adopted the MODS technique in this study because it had a lower cost and shorter time to susceptibility detection of about 5–11 days [ 31 – 33 ], though in this study, average was 9 days. It was also safer to perform the MODS technique, since it needed less stringent biosafety requirements such as a level 2 laboratory [ 34 ]. Laboratories at this biosafety level abound in the country and so MODS could be effectively decentralized and samples pooled from adjoining genexpert sites. The sensitivity and specificity of the MODS technique has been shown to outperform the conventional LJ method DST [ 30 , 35 – 37 ]. The second line cut-offs (Ofloxacin-1.0µg, Capreomycin-2.5µg, Amikacin-2µg, and Kanamycin-5.0µg) were adapted from the study by Trollip et al who had demonstrated a correlation of this cut-offs when using MODS with other standard phenotypic techniques [ 38 ]. A limitation of the study was that we adopted indirect first- and second-line MODS due to the infrequent detection of rifampicin resistance. It was more cost effective to run direct MODS in batches of at least 10 specimens. Conclusion With the current MDR-TB treatment algorithm and lack of support for susceptibility testing, a significant number of patients with rifampicin mono-resistance are being treated as MDR-TB for prolonged periods. More tuberculosis culture facilities are therefore needed. This will go a long way to unmasking rifampicin mono-resistance and re-classifying DR-TB. Declarations Conflicts of interest None to declare Funding statement This work was supported by the Association for Reproductive and Family Health (ARFH), FHI 360 KNCV and OMS Medicare Clinic and Research Center Author Contribution E.A.O . and D.A.J.M. conceived the study. Material preparation, data collection and analysis were performed by E.A.O., U.A.U., A.A.O, A.U.E., D.A.J.M. E.A.O., U.A.U., A.A.O, A.U.E., D.A.J.M. and C.I. wrote the main manuscript text and prepared the figure. All authors discussed the results and contributed substantially to the final manuscript. Acknowledgement We deeply appreciate the Association for Reproductive and Family Health (ARFH) and FHI 360 who provided the XpertMTB/Rif machines, KNCV who supported sites with XpertMTB/Rif Cartridges and OMS Medicare Clinic and Research Center, Calabar, Nigeria. 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Zürcher K, Ballif M, Fenner L, Borrell S, Keller PM, Gnokoro J, Marcy O, Yotebieng M, Diero L, Carter EJ, Rockwood N, Wilkinson RJ, Cox H, Ezati N, Abimiku AG, Collantes J, Avihingsanon A, Kawkitinarong K, Reinhard M, Hömke R, Huebner R, Gagneux S, Böttger EC, Egger M, International epidemiology Databases to Evaluate AIDS (IeDEA) consortium. (2019). Drug susceptibility testing and mortality in patients treated for tuberculosis in high-burden countries: a multicentre cohort study. Lancet Infect Dis. 2019;19(3):298–307. doi: 10.1016/S1473-3099(18)30673-X. Epub 2019 Feb 8. PMID: 30744962; PMCID: PMC6482382. Naidoo K, Perumal R, Ngema SL, Shunmugam L, Somboro AM. (2023). Rapid Diagnosis of Drug-Resistant Tuberculosis-Opportunities and Challenges. Pathogens. 2023;13(1):27. 10.3390/pathogens13010027 Araoye MO. Research Methodology with Statistics for Health and Social Sciences. Ilorin: Nathadex; 2004. pp. 115–21. Coronel J, Roper M, Caviedes L, Moore DAJ. MODS User Guide version 12.1. 2008 http://www.modsperu.org.Accessed06/07/2014 Ullah I, Shah AA, Basit A, Ali M, Khan A, Ullah U, et al. Rifampicin resistance mutations in the 81 bp RRDR of rpoB gene in Mycobacterium tuberculosis clinical isolates using XpertMTB/RIF in Khyber Pakhtunkhwa, Pakistan: a retrospective study. BMC Inf Dis. 2016;16:413. Audu ES, Gambo MS, Yakubu AA. Rifampicin resistant mycobacterium tuberculosis in Nasarawa State, Nigeria. Niger J Basic Clin Sci. 2017;14:21–5. Nigeria National Tuberculosis and Leprosy Control Programme (NNTBLCP). National drug resistant Tuberculosis prevalence survey report 2012 . Federal Ministry of Health Abuja, Nigeria. Kurbatova EV, Cavanaugh JS, Shah NS, Wright A, Kim HJ, Metchok B, et al. Rifampicin-resistant Mycobacterium tuberculosis : susceptibility to isoniazid and other anti-tuberculosis drugs. Int J Tuberc Lung Dis. 2012;16(3):355–7. 10.5588/ijtld.11.0542 . Smith SE, Kurbatova EV, Cavanaugh JS, Cegielski JP. Global isoniazid resistance patterns in rifampin-resistant and rifampin-susceptible tuberculosis. Int J Tuberc Lung Dis. 2012;16(2):203–5. 10.5588/ijtld.11.0445 . Moore DAJ, Evans CAW, Gilman RH, Caviedes L, Coronel J, Vivar A. Microscopic-Observation Drug-Susceptibility Assay for the Diagnosis of TB. N Eng J Med. 2006;355:1539–50. Ochang EA, Oduyebo OO, Onwuezobe IA, Collier D, Bode-Sojobi I, Odo M. Feasibility and cost analysis of programmatic implementation of Microscopic-Observation Drug Susceptibility (MODS) assay in Nigeria. Niger J Med. 2016;25(3):226–33. Minion J, Leung E, Menzies D, Pai M. Microscopic-Observation drug susceptibility and thin layer agar assays for the detection of drug resistant tuberculosis: a systematic review and meta-analysis. Lancet Infect Dis. 2010;10(10):688–98. Kim SJ, Lee SH, Kim IS, Kim HJ, Kim SK, Rieder HL. (2007) Risk of occupational tuberculosis in National Tuberculosis Programme laboratories in Korea. Int J Tuberc Lung Dis. 2007;11(2): 138–142. Oberhelman RA, Soto-Castellares G, Caviedes L, Castillo ME, Kissinger P, Moore DAJ, et al. Improved recovery of Mycobacterium tuberculosis from children using the microscopic observation drug susceptibility method. Pediatrics. 2006;118:100–6. Shiferaw G, Woldeamanuel Y, Gebeyehu M, Girmachew F, Demessie D, et al. Evaluation of Microscopic Observation Drug Susceptibility Assay for Detection of Multidrug-Resistant Mycobacterium tuberculosis . J Clin Microbiol. 2007;45(4):1093–7. Ha DTM, Lan NTN, Wolbers M, Duong TN, Quang ND, Thinh TTV et al. Microscopic Observation Drug Susceptibility Assay (MODS) for Early Diagnosis of Tuberculosis in Children. PLoS ONE. 2009;4(12). Available: http/www.plosone.com.Accessed27/07/2017 Trollip AP, Moore D, Coronel J, Caviedes L, Klages S, Victor T, et al. Second-line drug susceptibility breakpoints for Mycobacterium tuberculosis using the MODS assay. Int J Tuberc Lung Dis. 2014;18(2):227–32. Additional Declarations No competing interests reported. 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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-5424699","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":384681642,"identity":"5a9c0c94-d81f-40b8-b916-16a5ea3f784a","order_by":0,"name":"Ernest Afu Ochang","email":"","orcid":"","institution":"University of Calabar","correspondingAuthor":false,"prefix":"","firstName":"Ernest","middleName":"Afu","lastName":"Ochang","suffix":""},{"id":384681643,"identity":"68276aba-cd2f-43ef-a262-b2cb47bfefda","order_by":1,"name":"Ubong Aniefiok Udoh","email":"","orcid":"","institution":"University of Calabar","correspondingAuthor":false,"prefix":"","firstName":"Ubong","middleName":"Aniefiok","lastName":"Udoh","suffix":""},{"id":384681645,"identity":"0e94fdb9-6668-4cb7-abda-a9239224fc9f","order_by":2,"name":"Akaninyene Asuquo Otu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuElEQVRIiWNgGAWjYDACHgglB2cRqSWBwZh0LYkNRGvh7zn87MHHH4fTNxw/e/DBBwY7Od0GAlokzraZG85IOJy74UxesuEMhmRjswOErDnPYCbNA9JyIAfIYDiQuI2QFvnz7N9AWtINzr8hUovB2R6wLQkGN4i1xfDMmTLJGWnphjNvvDE2nGFAhF/kzqRvk/hgYy3Pdz7H8MGHCjs5wt6HAQWwSgNilYOAfAMpqkfBKBgFo2BEAQA6gkIwH0UmHwAAAABJRU5ErkJggg==","orcid":"","institution":"University of Calabar","correspondingAuthor":true,"prefix":"","firstName":"Akaninyene","middleName":"Asuquo","lastName":"Otu","suffix":""},{"id":384681648,"identity":"03379e72-652d-4518-ad5a-d869a93ed777","order_by":3,"name":"Atana Uket","email":"","orcid":"","institution":"University of Calabar","correspondingAuthor":false,"prefix":"","firstName":"Atana","middleName":"","lastName":"Uket","suffix":""},{"id":384681650,"identity":"e654fca2-6f6f-41ca-9db8-f06f26c4c13f","order_by":4,"name":"Chibuke Ibe","email":"","orcid":"","institution":"University of the Free State","correspondingAuthor":false,"prefix":"","firstName":"Chibuke","middleName":"","lastName":"Ibe","suffix":""},{"id":384681651,"identity":"267300d7-bbb0-457d-af31-55752aeceafb","order_by":5,"name":"David A. J. Moore","email":"","orcid":"","institution":"London School of Hygiene \u0026 Tropical Medicine","correspondingAuthor":false,"prefix":"","firstName":"David","middleName":"A. J.","lastName":"Moore","suffix":""}],"badges":[],"createdAt":"2024-11-10 07:23:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5424699/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5424699/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12982-025-00926-7","type":"published","date":"2025-09-04T15:57:19+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":71888456,"identity":"5280a1a2-fde2-4329-ab4c-56f10519bba4","added_by":"auto","created_at":"2024-12-19 12:39:37","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":210713,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFlow diagram depicting steps in sample selection and specimen processing.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5424699/v1/2ee3a5bfaa52a7681eced7bf.jpg"},{"id":90828071,"identity":"aae3278f-caa8-4889-9453-28f3ac3d15ac","added_by":"auto","created_at":"2025-09-08 16:05:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":992336,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5424699/v1/9cc391f8-1da7-4dc1-a06d-b86c43ecf068.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Unmasking rifampicin mono-resistance in tuberculosis patients in Cross River State, Nigeria","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAbout 2\u0026nbsp;billion people (one quarter of the world\u0026rsquo;s population) are infected with \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e, the causative organism for tuberculosis which has accounted for about 1.3\u0026nbsp;million deaths( WHO 2023) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Currently, Nigeria has a tuberculosis incidence of 361,000 with an incidence rate of 219/100,000 amongst a population of 191\u0026nbsp;million [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe emergence and spread of strains resistant to anti-tuberculosis chemotherapy has grossly undermined global control efforts [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Several strains resistant to rifampicin and isoniazid, described as multi-drug resistant tuberculosis (MDR-TB) and some MDR-TB also resistant to aminoglycosides and quinolones described as extensively drug resistant tuberculosis (XDR-TB) have continued to spread across the world [\u003cspan additionalcitationids=\"CR6 CR7\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Recently, totally drug resistant tuberculosis (TDR-TB) strains have also emerged [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. MDR/RRTB incidence rate in Nigeria is estimated at 12/100,000 population with the proportion of MDR/RRTB patients estimated to have MDR-TB put at 66% [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFollowing the endorsement of XpertMTB/Rif (Cepheid Inc. CA USA) popularly referred to as Genexpert by the WHO for prompt detection of tuberculosis, it was deployed into the Nigerian National Tuberculosis Programme in 2015 [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This real time multiplex polymerase chain reaction technology rapidly detects organisms of the \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e complex and rifampicin resistance [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. It has significantly improved tuberculosis diagnosis in the country [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The operational algorithm for XpertMTB/Rif used in Nigeria recommends commencement of MDR-TB treatment on rifampicin resistance detection and subsequent re-direction of therapy after phenotypic drug susceptibility testing (DST) [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The WHO in 2016, published guidelines for MDR-TB care of 20 months duration but suggested a possible short course of 12 months for rifampicin mono-resistant patients [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. This can only be implemented with increased access to DST. Most DST facilities in the country are however still not functional and all specimens are shipped to the National reference laboratory in Zaria, Kaduna State [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. With the current dearth of phenotypic DST facilities in Nigeria for the quick delineation of DR-TB cases, several rifampicin mono-resistant TB patients may be inappropriately placed on toxic second line drugs used for MDR-TB treatment for prolonged periods before DST results are available [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. We decided to determine the proportion of non MDR-TB patients enrolled for treatment following rifampicin resistance detection with XpertMTB/Rif in Cross River State and possibly document evidence for the concomitant deployment of cheaper, safer alternative \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e culture methods in National programmes across resource limited settings.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy setting/subjects selection\u003c/h2\u003e \u003cp\u003eThis study was coordinated from the Department of Medical Microbiology and Parasitology, University of Calabar Teaching Hospital (UCTH) Calabar, Cross River State, Nigeria from June 2015 to July 2016. Patients presenting with presumptive diagnosis of tuberculosis (patients with \u0026ge;\u0026thinsp;2 of cough\u0026thinsp;\u0026ge;\u0026thinsp;2 weeks, fever, excessive night sweats, weight loss and history of contact with a patient with tuberculosis) [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] at 10 facilities across the State, with capacity for smear microscopy and genexpert were enrolled. Paediatric patients (patients\u0026thinsp;\u0026lt;\u0026thinsp;16 years of age) with a National TB and Leprosy Control Programme (NTBLCP)/WHO risk score\u0026thinsp;\u0026ge;\u0026thinsp;7 and those with score\u0026thinsp;\u0026le;\u0026thinsp;7 but unresponsive to high dose broad spectrum antibiotics [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] were also included. Patients who had already commenced anti-tuberculosis medication were excluded since they could be excreting dead (non-cultivable) bacilli. Written informed consent was obtained from all participants. Where the participants were under 18, written informed consent was obtained from a parent and/or legal guardian.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEthical consideration\u003c/h3\u003e\n\u003cp\u003e \u003cstrong\u003eEthics approval\u003c/strong\u003e \u003cp\u003e was obtained from the University of Calabar Teaching Hospital (UCTH) Health Research Ethics Committee (UCTH/HREC/33/259) and the Cross River State Human Research Ethics Committee (CRS/MH/CGS/E-H/018/Vol.II/119). The research was carried out following the guidelines of the ethics committees.\u003c/p\u003e \u003c/p\u003e\n\u003ch3\u003eSample size\u003c/h3\u003e\n\u003cp\u003eThe minimum sample size was calculated using the formula n\u0026thinsp;=\u0026thinsp;\u003cem\u003ez\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u003cem\u003epq/d\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e, where: n\u0026thinsp;=\u0026thinsp;desired sample size (when population is greater than 10,000), z\u0026thinsp;=\u0026thinsp;the standard normal deviation which corresponds to 95% confidence level set at 1.96, p\u0026thinsp;=\u0026thinsp;proportion of target population, q\u0026thinsp;=\u0026thinsp;1-\u003cem\u003ep\u003c/em\u003e and d\u0026thinsp;=\u0026thinsp;desired degree of accuracy set at 0.05 [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. A WHO incidence of 66% of MDR among MDR/RR-TB\u003csup\u003e2\u003c/sup\u003e was used to estimate a minimum sample size of tuberculosis positive cases of 344. A10% attrition was added to bring the minimum sample size of positive cases to 378.\u003c/p\u003e\n\u003ch3\u003eSpecimen collection and processing\u003c/h3\u003e\n\u003cp\u003eTwo sputum specimens were obtained by expectoration (one of which was an early morning specimen) from all adults and older children who could expectorate. Two early morning gastric aspirate were obtained from those less than 3 years of age who could not expectorate. In patients with suspected extra pulmonary tuberculosis, aspirates (lymph node, ascitic fluid, peritoneal fluid, pericardial fluid and cerebrospinal fluid) were collected according to the possible site of infection. Specimens were preserved at 2-8\u003csup\u003eo\u003c/sup\u003eC until processed but not for longer than three days from the date of production.\u003c/p\u003e \u003cp\u003eAll processes were carried out by trained personnel. XpertMTB/Rif was performed as described in the standard operating procedure manual [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This was done by inoculating the XpertMTB/Rif cartridge with specimen, which was inserted into the machine within 30 minutes of inoculation. The XpertMTB/Rif machine would then automatically complete the gene extraction process and detect both \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e and the presence of mutations in the \u003cem\u003erpoB\u003c/em\u003e gene which codes for rifampicin resistance. Rifampicin resistant specimens were sent to UCTH Calabar and Dr. Lawrence Henshaw Memorial Hospital Calabar for LJ culture. Indirect MODS Phenotypic DST was then performed in the Mycobacteriology Research Laboratory, Department of Medical Microbiology and Parasitology, UCTH, Calabar. Due to a lack of equipment and capacity in other sites extra pulmonary specimens were evaluated in UCTH only.\u003c/p\u003e \u003cp\u003eAll LJ media were prepared in-house using standard protocol. Culture involved a decontamination step using the Sodium Hydroxide-Sodium Citrate-N-Acetyl Cysteine (NaOH-NALC) method. After centrifugation and discard of supernatant, the resulting pellet was inoculated on two LJ slants.\u003c/p\u003e \u003cp\u003eMODS was carried out as described in the technique for preparation of positive controls in the MODS protocol manual [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Indirect MODS assay was chosen instead of direct MODS to avoid wastage that could have arisen from testing single samples as they arrived the laboratory, since the detection of Rifampicin resistance was infrequent. This was done by harvesting colonies of \u003cem\u003eM. tuberculosis\u003c/em\u003e from LJ cultures (using sterile loops) into sterile tubes containing 100\u0026micro;l of water-tween-80 solution and six sterile glass beads. The tubes were vortexed for 2 minutes, allowed to stand for 5 minutes, then vortexed again for 20 seconds after adding 3ml of water-tween-80 solution and allowed to stand for another 30 minutes. The supernatant was transferred to another tube and its turbidity adjusted to 0.5 McFarland turbidity equivalent before culturing. During culture, 5\u0026micro;l of the 0.5 McFarland adjusted suspensions were added to 5ml of supplemented Middlebrook 7H9 broth. The preparations were cultured in 24-well tissue culture plates as described for processing positive controls in the MODS protocol. Two wells in each of 4 rows of the 24-well plate contained isoniazid and rifampicin at final diluted concentrations of 0.4\u0026micro;g/ml and 1\u0026micro;g/ml respectively. The plates were placed in ziploc bags and incubated at 37\u003csup\u003e\u0026deg;\u003c/sup\u003eC. A different plate was used for susceptibility testing of second line drugs with the following final concentrations; Flouroquinolones (Ofloxacin-1.0\u0026micro;g), Injectables (Capreomycin-2.5\u0026micro;g, Amikacin-2\u0026micro;g, and Kanamycin-5.0\u0026micro;g).\u003c/p\u003e \u003cp\u003eCultures were examined with an inverted microscope every alternate day from day 5 to 21. \u003cem\u003eM. tuberculosis\u003c/em\u003e was identified by characteristic serpentine cord-like growth on inverted microscopy. Positive controls using previously LJ evaluated MDR and mono-resistant strains of \u003cem\u003eM. tuberculosis\u003c/em\u003e were cultured after the specimens had been secured in the ziploc bags to prevent cross contamination. Culture media without samples were added to one row of wells in each plate as negative control. Specimens were regarded as positive if\u0026thinsp;\u0026ge;\u0026thinsp;2 colony forming units (CFU) were seen in the drug free wells and negative if none was seen. Wells with only 1CFU were regarded as indeterminate and the test repeated. Isolates were regarded as susceptible to any drug if no CFU was seen in the drug containing wells read on the same day as the drug free wells, and resistant if\u0026thinsp;\u0026ge;\u0026thinsp;2CFU were seen. Drug containing wells with 1CFU were regarded as indeterminate and the test repeated. Contaminated cultures were reprocessed.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eAll data was analyzed using the Statistical Package for Social Sciences (SPSS) software version 20.0. (SPSS Inc. Chicago, USA). Categorical data are presented as %(n) when data was available for all participants and as %(n/sample size) when data was only available for a subset of the study population. The χ\u003csup\u003e2\u003c/sup\u003e test was used to compare categorical data between groups. All p-values are two-sided and a p-value of \u0026lt;\u0026thinsp;0.05 was considered to be statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 3,580 presumptive tuberculosis cases were recruited from 10 Genexpert sites in Cross River State, Nigeria. This included 53.1% (1904) females and 46.7% (1674) males with sex not indicated in 0.2% (8) of cases. Of the 98.9% (3541/3579) of patients whose ages were appropriately indicated, the mean age was 38.16 years and ranged from 10 months to 92 years. A total of 97.8% (3499) of specimens were sputum while 2.2% (80) were extra-pulmonary with pleural fluid, gastric aspirate, lymph node aspirate and ascitic fluid predominating (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). It was observed that multiple re-testing at different sites with eventual multiple capture of patients into the national data was common. All multiple entries identified by similarity of names, sex and/or age were expunged from our data set.\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\u003eDistribution of TB according to specimens\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\"\u003e \u003cp\u003eSpecimen type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eGenexpert Positive\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscitic fluid (n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLung tissue-Autopsy Specimen (n\u0026thinsp;=\u0026thinsp;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(100.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCSF(n\u0026thinsp;=\u0026thinsp;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGastric Aspirate (n\u0026thinsp;=\u0026thinsp;22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(4.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKnee Joint Aspirate(n\u0026thinsp;=\u0026thinsp;1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLumbar Aspirate (n\u0026thinsp;=\u0026thinsp;1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLymph node biopsy (n\u0026thinsp;=\u0026thinsp;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLymph node aspirate (n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(45.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePleural Fluid (n\u0026thinsp;=\u0026thinsp;27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(14.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSputum (n\u0026thinsp;=\u0026thinsp;3500)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e751\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(21.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTissue Biopsy (n\u0026thinsp;=\u0026thinsp;1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal TB Positive (n\u0026thinsp;=\u0026thinsp;3580)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e763\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(21.3)\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 \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e was detected in 21.3% (763) of the presumptive cases of which 4.6% (35/763) were rifampicin resistant. All rifampicin resistant specimens were from sputum samples. On LJ culture, growth was achieved from 89.6% (31/35) of specimens that were rifampicin resistant on genexpert. Using MODS first and second line, 32.2% (10/31) and 64.5% (20/31) were rifampicin mono-resistant and MDR respectively, while one XDR isolate was identified (Fig.\u0026nbsp;1). It was resistant to ofloxacin and the aminoglyosides (capreomycin, kanamycin, and amikacin). This was confirmed in the National TB reference laboratory Zaria and the patient enrolled on XDR-TB treatment.\u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure\u0026nbsp;1. Flow diagram depicting steps in sample selection and specimen processing.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eWhen categorized into treatment groups, 25.7% (27/105) and 1.2% (8/658) of the rifampicin resistant patients belonged to retreatment and new patients respectively (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). There was a cluster of TB and DR-TB between the ages of 21\u0026ndash;50 years (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). There was no correlation between rifampicin mono-resistance and MDR-TB with gender (χ2\u0026thinsp;=\u0026thinsp;0.793, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.308) or HIV status (χ2\u0026thinsp;=\u0026thinsp;0.416, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.398). Patients who presented with first line treatment failure were most likely to have MDR-TB (χ2\u0026thinsp;=\u0026thinsp;9.121, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.028) Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOver 90% of resistance to rifampicin is attributable to mutations in the 81bp region of the \u003cem\u003erpoB\u003c/em\u003e gene known as the Rifampicin Resistant Determinant Region (RRDR) [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The Cepheid XpertMTB/Rif uses molecular beacons to probe five overlapping regions in the RRDR. These probes are represented as Probe A (507\u0026ndash;511), Probe B (512\u0026ndash;518), Probe C (518\u0026ndash;523), Probe D (523\u0026ndash;529) and Probe E (529\u0026ndash;533) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Rifampicin remains the most important drug in the management of tuberculosis and resistance to it, is assumed to suggest a possible resistance to other first line anti-TB drugs. With the advent of genexpert, it has become easier to detect rifampicin resistance in many resource poor settings. Unfortunately, there appears to be a mindset shift from providing required support for full drug susceptibility testing which should promptly re-define treatment.\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\u003eDistribution of DR-TB according to patient treatment category\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\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTB Status\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCategory\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eXpert Rifampicin Resistant\u003c/p\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMDR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRifampicin Mono-resistant\u003c/p\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRetreatment (n\u0026thinsp;=\u0026thinsp;105)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27(25.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18(17.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(5.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNew (n\u0026thinsp;=\u0026thinsp;658)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8(1.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(1.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4(0.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal (n\u0026thinsp;=\u0026thinsp;763)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35(4.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21(2.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10(1.3)\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=\"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\u003eAge related distribution of TB and DR-TB in genexpert tested presumptive TB patients.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eAge group\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTB Positive\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGenexpert Rif Resistant\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRif Mono-Resistant\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMDR\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u0026ndash;5 (n\u0026thinsp;=\u0026thinsp;44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5(0.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u0026ndash;10(n\u0026thinsp;=\u0026thinsp;98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(1.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11\u0026ndash;15(n\u0026thinsp;=\u0026thinsp;131)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13(1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16\u0026ndash;20(n\u0026thinsp;=\u0026thinsp;164)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e47(6.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2(5.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(4.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e21\u0026ndash;25(n\u0026thinsp;=\u0026thinsp;335)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e104(13.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1(2.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e26\u0026ndash;30(n\u0026thinsp;=\u0026thinsp;421)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e96(12.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4(11.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(14.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e31\u0026ndash;35(n\u0026thinsp;=\u0026thinsp;537)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e157(20.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8(22.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2(20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5(23.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e36\u0026ndash;40(n\u0026thinsp;=\u0026thinsp;359)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80(10.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10(28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3(30.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(28.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e41\u0026ndash;45(n\u0026thinsp;=\u0026thinsp;396)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e88(11.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4(11.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(9.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e46\u0026ndash;50(n\u0026thinsp;=\u0026thinsp;255)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e43(5.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(8.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(9.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e51\u0026ndash;55(n\u0026thinsp;=\u0026thinsp;247)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38(5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1(2.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(4.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e56\u0026ndash;60(n\u0026thinsp;=\u0026thinsp;198)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31(4.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e61\u0026ndash;65(n\u0026thinsp;=\u0026thinsp;122)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(1.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1(2.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(4.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e66\u0026ndash;70(n\u0026thinsp;=\u0026thinsp;87)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15(2.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1(2.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e71\u0026ndash;75(n\u0026thinsp;=\u0026thinsp;88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8(1.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e76\u0026ndash;80(n\u0026thinsp;=\u0026thinsp;26)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2(0.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e81\u0026ndash;85(n\u0026thinsp;=\u0026thinsp;19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3(0.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e86\u0026ndash;90(n\u0026thinsp;=\u0026thinsp;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e91\u0026ndash;95(n\u0026thinsp;=\u0026thinsp;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0(0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e752(100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35(100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10(100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21(100)\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=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCorrelates of Drug resistant tuberculosis\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRif Mono-Resistant\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMDR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eχ2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003edf\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eHIV Status\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePositive(n\u0026thinsp;=\u0026thinsp;16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.416\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.398\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNegative(n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal(n\u0026thinsp;=\u0026thinsp;31)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e10\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e21\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eSex\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale(n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.793\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.308\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale(n\u0026thinsp;=\u0026thinsp;19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal(n\u0026thinsp;=\u0026thinsp;31)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e10\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e21\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eTreatment Category\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNew (n\u0026thinsp;=\u0026thinsp;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFailure(n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e9.121\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.028\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRAD(n\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRelapse(3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal(31)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e10\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e21\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn our study, 4.6% of all TB was rifampicin resistant, lower than a 12.1% resistance reported in Nasarawa State, Nigeria [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. We also found a rifampicin mono-resistance of 32.2%., close to the 39.1% (45/115) prevalence detected in a Nigerian national survey conducted in 2012 using the Molecular Line Probe assay [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Kurbatova and colleagues on evaluating data from several supra-national tuberculosis reference laboratories across the world had noted a high proportion of rifampicin-resistant isoniazid-susceptible tuberculosis and issued caution on the universal application of MDR-TB treatment based on genexpert results [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. In another retrospective evaluation of data from several centers globally, variations ranging from 14\u0026ndash;45% directly proportional to the MDR-TB burden of the country were observed [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. These authors also observed that rifampicin mono-resistant isolates were more likely to be susceptible to other second-line drugs than MDR strains. They re-enforced the need for isoniazid testing before commencement of MDR-TB treatment. The WHO global tuberculosis report 2018 also reported a 66% estimate of MDR among MDR/RR-TB patients [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe universal enrolment of patients with genexpert detected rifampicin resistance into MDR-TB treatment does not also consider patients with possible dormant \u003cem\u003erpoB\u003c/em\u003e genes. In India 4.6% of isolates initially diagnosed as resistant to rifampicin by XpertMTB/RIF, tested susceptible to rifampicin by phenotypic DST [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. These strains of \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e although not encountered in our study, bear dormant \u003cem\u003erpoB\u003c/em\u003e mutations and demonstrate phenotypic and clinical rifampicin susceptibility.\u003c/p\u003e \u003cp\u003eWe adopted the MODS technique in this study because it had a lower cost and shorter time to susceptibility detection of about 5\u0026ndash;11 days [\u003cspan additionalcitationids=\"CR32\" citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], though in this study, average was 9 days. It was also safer to perform the MODS technique, since it needed less stringent biosafety requirements such as a level 2 laboratory [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Laboratories at this biosafety level abound in the country and so MODS could be effectively decentralized and samples pooled from adjoining genexpert sites. The sensitivity and specificity of the MODS technique has been shown to outperform the conventional LJ method DST [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan additionalcitationids=\"CR36\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. The second line cut-offs (Ofloxacin-1.0\u0026micro;g, Capreomycin-2.5\u0026micro;g, Amikacin-2\u0026micro;g, and Kanamycin-5.0\u0026micro;g) were adapted from the study by Trollip et al who had demonstrated a correlation of this cut-offs when using MODS with other standard phenotypic techniques [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. A limitation of the study was that we adopted indirect first- and second-line MODS due to the infrequent detection of rifampicin resistance. It was more cost effective to run direct MODS in batches of at least 10 specimens.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWith the current MDR-TB treatment algorithm and lack of support for susceptibility testing, a significant number of patients with rifampicin mono-resistance are being treated as MDR-TB for prolonged periods. More tuberculosis culture facilities are therefore needed. This will go a long way to unmasking rifampicin mono-resistance and re-classifying DR-TB.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflicts of interest\u003c/h2\u003e \u003cp\u003eNone to declare\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding statement\u003c/h2\u003e \u003cp\u003eThis work was supported by the Association for Reproductive and Family Health (ARFH), FHI 360 KNCV and OMS Medicare Clinic and Research Center\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eE.A.O . and D.A.J.M. conceived the study. Material preparation, data collection and analysis were performed by E.A.O., U.A.U., A.A.O, A.U.E., D.A.J.M. E.A.O., U.A.U., A.A.O, A.U.E., D.A.J.M. and C.I. wrote the main manuscript text and prepared the figure. All authors discussed the results and contributed substantially to the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe deeply appreciate the Association for Reproductive and Family Health (ARFH) and FHI 360 who provided the XpertMTB/Rif machines, KNCV who supported sites with XpertMTB/Rif Cartridges and OMS Medicare Clinic and Research Center, Calabar, Nigeria.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eFurther data from this study is available upon request\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWorld Health Organization. Global tuberculosis report 2017. WHO/HTM/TB/2017.11. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.who.int/iris/handle/10665/259366\u003c/span\u003e\u003cspan address=\"http://www.who.int/iris/handle/10665/259366\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 04/05/2018.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWorld Health Organization. Global tuberculosis report 2018. WHO/CDS/TB/2018.20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.who.int/tb/publications/global_report/en/Accessed04/02/2019\u003c/span\u003e\u003cspan address=\"https://www.who.int/tb/publications/global_report/en/Accessed04/02/2019\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFederal Ministry Of Health. (FMoH 2023) National Strategic Plan for Tuberculosis Control 2021\u0026ndash;2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZine S, Patankar SA, Raopati SS. Rise of antibiotic resistance in tuberculosis. Res J Pharm Technol. 2018;11(7):3201\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRamazanzadeh R, Sayhemiri K. 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Available: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp/www.plosone.com.Accessed27/07/2017\u003c/span\u003e\u003cspan address=\"http://www.plosone.com.Accessed27/07/2017\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTrollip AP, Moore D, Coronel J, Caviedes L, Klages S, Victor T, et al. Second-line drug susceptibility breakpoints for Mycobacterium tuberculosis using the MODS assay. Int J Tuberc Lung Dis. 2014;18(2):227\u0026ndash;32.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Public Health](https://link.springer.com/journal/12982)","snPcode":"12982","submissionUrl":"https://submission.springernature.com/new-submission/12982/3","title":"Discover Public Health","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"XpertMTB/Rif, Genexpert, MDR-TB, DR-TB, Drug Susceptibility Testing, Mycobacterium tuberculosis","lastPublishedDoi":"10.21203/rs.3.rs-5424699/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5424699/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eCurrent tuberculosis management algorithm in Nigeria recommends commencement of multi-drug resistant tuberculosis (MDR-TB) treatment on rifampicin resistance detection, following XpertMTB/Rif (Genexpert) test and subsequent re-direction of therapy after phenotypic drug susceptibility testing. With the current dearth of phenotypic drug susceptibility testing facilities in Nigeria, for quick and precise identification of drug resistant tuberculosis, several rifampicin mono-resistant tuberculosis patients may be inappropriately placed on toxic second line drugs used for MDR-TB treatment for prolonged periods before susceptibility results are available.\u003c/p\u003e\u003ch2\u003eMethod\u003c/h2\u003e \u003cp\u003eXpertMTB/Rif were performed on a total of 3,580 patient samples from 10 sites across Cross River State, Nigeria as a prospective cross sectional study. Rifampicin resistant specimens were reprocessed and cultured on Lowenstein Jensen medium. Indirect susceptibility testing following the microscopic observation drug susceptibility technique was performed using Rifampicin (1 \u0026micro;g/ml), Isoniazid (0.4 \u0026micro;g/ml), Flouroquinolone (Ofloxacin-1.0 \u0026micro;g), Capreomycin (2.5 \u0026micro;g/ml), Amikacin (2 \u0026micro;g/ml) and Kanamycin (5.0 \u0026micro;g/ml).\u003c/p\u003e\u003ch2\u003eResult\u003c/h2\u003e \u003cp\u003e \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e was detected in 21.3% (763) of the 3,580 presumptive tuberculosis cases recruited, of which 4.6% (35/763) were resistant to rifampicin. Culture yielded isolates from 89.6% (31/35) of these rifampicin resistant cases while susceptibility testing using first and second line antimicrobials, revealed 32.2% (10/31) and 64.5% (20/31) rifampicin mono-resistant and MDR-TB respectively. When categorized into treatment groups, 25.7% (27/105) and 1.2% (8/658) of patients with rifampicin resistance belonged to retreatment and na\u0026iuml;ve patient groups respectively. There was no correlation between rifampicin mono-resistant and MDR-TB with gender (χ2\u0026thinsp;=\u0026thinsp;0.793, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.308) or HIV status (χ2\u0026thinsp;=\u0026thinsp;0.416, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.398). Patients who presented with first line treatment failure were most likely to have MDR-TB (χ2\u0026thinsp;=\u0026thinsp;9.121, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.028).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eWith the current MDR-TB treatment algorithm and lack of programmatic support for drug susceptibility testing, a significant number of patients with rifampicin mono-resistance are treated as MDR-TB for prolonged periods. More programmatic support and scale up of simpler susceptibility techniques are required.\u003c/p\u003e","manuscriptTitle":"Unmasking rifampicin mono-resistance in tuberculosis patients in Cross River State, Nigeria","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-19 12:38:18","doi":"10.21203/rs.3.rs-5424699/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-12-19T16:41:26+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-05T01:43:24+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-01T05:40:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"263138283173201648374145393760910978388","date":"2024-12-01T04:40:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"58039290991402194816454555140932325761","date":"2024-11-25T12:05:14+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-11-25T10:06:23+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-11-21T14:47:18+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-11-20T18:19:35+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Public Health","date":"2024-11-10T07:17:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Public Health](https://link.springer.com/journal/12982)","snPcode":"12982","submissionUrl":"https://submission.springernature.com/new-submission/12982/3","title":"Discover Public Health","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cf044c09-cded-4dcd-b929-4142fb949f41","owner":[],"postedDate":"December 19th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-09-08T16:03:37+00:00","versionOfRecord":{"articleIdentity":"rs-5424699","link":"https://doi.org/10.1186/s12982-025-00926-7","journal":{"identity":"discover-public-health","isVorOnly":false,"title":"Discover Public Health"},"publishedOn":"2025-09-04 15:57:19","publishedOnDateReadable":"September 4th, 2025"},"versionCreatedAt":"2024-12-19 12:38:18","video":"","vorDoi":"10.1186/s12982-025-00926-7","vorDoiUrl":"https://doi.org/10.1186/s12982-025-00926-7","workflowStages":[]},"version":"v1","identity":"rs-5424699","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5424699","identity":"rs-5424699","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}