Molecular study of Salmonella typhimurium integrons gene isolated from food sources and the effect of probiotic Bifidobacterium bifidum on its expression by Real time PCR

Background: Salmonella belongs to the family of Enterobacteriaceae, an intestinal, gram negative, and anaerobic bacterium. Salmonella affects a wide range of vertebrates, mainly through direct and indirect contact with the infected source. Salmonellosis is a dangerous infectious disease and a common human-animal disease. The integron (int) gene is effective in drug resistance and bacterial proliferation in the host body and can be an important factor in drug resistance of bacteria. The aim of this study was to investigate the molecular character of Salmonella typhimurium integron gene from food sources and the effect of probiotic Bifidobacterium bifidum on its expression by Real time PCR. Methods: In the present study, 138 food samples (milk, meat, poultry, fish, etc.) were isolated from Arak in order to promote the project. After centrifugation, the supernatant was kept in sterile crucible at 4 ° C for further experiments. Selective media were MacConkey Agar (MC) Salmonella-Shigella (SS) agar, bismuth sulfite agar transfected and incubated for 24 hours at 37 ° C. Results: From 138 food samples, 12 Salmonella typhimurium isolates were isolated by biochemical method. Polymerase Chain Reaction (PCR) was used to differentiate and detect the presence of integron gene. Salmonella typhimurium is of the highest importance in human, animal and poultry pathogens and is a common cause of fecal and foodborne illness worldwide. Conclusion: In this study, the Fold Change for intI gene was -1.13 which indicates that this gene was decreased by 13.1 fold in the treated group compared to the untreated group. Bifidobacterium bifidum showed integron gene expression. In fact, the combination of probiotic bifidobacterium bifidum with conventional antimicrobial drugs has shown good antibacterial effects against Salmonella spp.