Phylogenic Relationship of Salmonella Serovars Isolated from Different Foodstuffs in Isfahan

Background and objectives: are divided into two species: Salmonella enterica and Salmonella Salmonella bongori. S. enterica has more than 2,500 serotypes. Serovars of S. enterica such as Typhimurium, Enteritidis, Paratyphi B, Paratyphi A and Newport are associated with human infections. Approximately 75% of human Salmonella infections have been associated with contaminated food such as eggs, chicken, beef, pork, dairy products, fruits and vegetables. The aim of this study was to determine the frequency of Salmonella strains isolated from various food sources in Isfahan, Iran. Methods: Forty Salmonella strains were isolated from 450 suspected cases referred to the veterinary reference laboratory of Isfahan Province. The isolates were identified by differential and serotyping tests and then confirmed by PCR. A phylogenic tree was constructed with 34 sequences by neighbor-joining method using the MEGA7 software (version 7.1). Results: Overall, 10 Salmonella serovars were isolated from 32 chicken meat, three beef and five egg shell samples. S. enterica serovar Ouakum (20%), S. Enteritidis (17.5%) and S. Typhimurium (17.5%) were the most common serovars, while S. enterica serovar Nitra (2.5%) was found as the least prevalent isolate. Conclusion: In this study, S. Typhimurium species is placed in different clusters along with sequences reported from different parts of the world, indicating that the serovars are circulating all over the world.