Molecular Characterization of Virulence Factors and Microbial Resistance of Different Bacterial Isolates in some Dairy Products

Abstract Background: Bacterial contamination of milk and dairy products is a common problem. Foodborne microbial diseases reason for 20 million cases annually in the world. In the last two years, foodborne diseases caused by the intake of dairy products have been mostly disturbed with Salmonella entertica, Listeria monocytogenes Escherichia coli 0157:H7 and Campylobacter jejune. Aim of the study is to isolate MDR bacteria in dairy product and study of molecular characterization of that isolates.Results: A total 30 out of 131 bacterial isolates were MDR and distributed as 50 % from white cheese, 36.7% from industrial white cheese, 13.3 from old cheese and 6.6 % roomy cheese. The incidence of MDR bacterial isolates revealed the abundance of Staphylococcus sp. with 43.3% among all the tested bacterial isolates, while the other tested isolates showed Bacillus sp 16.7%, Salmonella 13.3%, E.coli 10 %, Enterococcus 6.7 % Psedoumonas 3.3 %, Shegella 3.3 % and Proteous 3.3 %. Molecular studies of genes presence or absence for class A (TEM, CTX and BSHV), class B (VIM, IMP, KPC and NDM), class C (FOX) and class D (OXA-10, OXA-24 and OXA-58) were tested. NDM, TEM, CITM and (OXA -10) genes were the most abundant the selected bacterial isolates.Conclusions: The results of this study indicate that cheese made from unpasteurized milk can pose a significant risk to consumers. Product manufacturing processes should be subject to health control-to-control pathogens. Reducing the surface area exposed to air reduces harmful microbial growth in dairy products.