Isolation, Antimicrobial resistance profiles and virulence genotyping of Salmonella spp. from food products in Mazandaran, northern Iran

Background: Salmonella is the most important source of food-borne infections around the world. Human salmonellosis is also found in fresh fruit and vegetable salads. Objective: to investigate detection of Salmonella spp.,  in Hamburger, Vegetable salads and Cream-filled pastries from factories, supermarkets, restaurants and local confectionery, Mazandaran, Iran, as well as, to assess their pathogenic potential and antimicrobial resistance. Methods: A total of 90 samples, 30 samples of each, were randomly collected. Biochemichal and serological test performed to detect the Salmonella spp. Antimicrobial susceptibility tests were determined by the disc diffusion method and virulent genes investigated performed by polymerase chain reaction (PCR) method. Results: 54 out of 90 samples were considered as Salmonella spp. by biochemical tests. Of which 46 (85.2%) were recovered by the 16S-23S rRNA PCR test. 19 samples were S. Typhimurium Serotypes (41.4%), 15 were S. enteritidis (32.7%), 2 were S. typhi (4.4%). Salmonella isolates were sensitive to all of the tested antibiotics, but they slightly exhibited resistance to ampicillin and Cefotaxime. All examined Salmonella serovars in this study showed positive amplification for the invA, spv, and ViaB genes virulence genes. Conclusion: These results would greatly help in understanding the prevalence of virulence genes and antibiotic sensitivity among Salmonella serovars in Hamburger, Vegetable salads and Cream-filled pastries