Virulence Gene Properties and Phylogenetic Relationship of Salmonella Serotypes Isolated from Different Sources in North of Iran

Background: Salmonella species can cause various infections in humans and animals. The presence of certain genes determines the virulence of a Salmonella serotype. Objectives: The current research endeavor was undertaken to assess the virulence characteristics and genotypic traits of Salmonella serotypes extracted from various sources within the geographical boundaries of Iran. Methods: Salmonella isolates, previously retrieved and preserved in the veterinary microbiology laboratory, underwent serotyping and polymerase chain reaction (PCR) identification of nine virulence-associated genes. Genotyping was carried out using random amplified polymorphic DNA-PCR (RAPD-PCR). Results: All Salmonella isolates showed the presence of invA, sdiA, hilA, and iroB virulence genes. There were a total of 17 different virulence gene patterns among Salmonella serotypes. The presence of fliC and sefA genes and their related patterns were significant among S. typhimurium and S. enteritidis serotypes, respectively (P < 0.05). In the RAPD-PCR fingerprinting, 11 distinct clusters were obtained, and 16 isolates (26.66%) were classified as untypeable strains. There was a significant association between RAPD genotypes and Salmonella serotypes (P < 0.05), while the association between these RAPD patterns and the source of the isolates was not significant (P > 0.05). Conclusions: According to the results, Salmonella serotypes from non-human sources carry significant virulence determinants and show similar genotypic patterns with human isolates. These findings provide valuable insights into the virulence properties and genetic diversity of Salmonella serotypes in Iran, which could inform the development of effective control and prevention strategies for salmonellosis in the region.