Molecular detection of invA and spv virulence genes in Salmonella enteritidis isolated from human and animals in Iran

Abstract

It is important to study the genotypic diversity of Salmonella plasmid genes which are responsible for its virulence. In the present study multiplex polymerase chain reaction (multiplex PCR) assay was carried out for detection of Salmonella enteritidisand presence of invA and spv genes. In the first stage of the study, 1001 poultry samples were collected from a slaughterhouse in Kerman province (southern Iran). Biochemical and serological tests were then performed for identification ofSalmonella serovars and 6.79% (68/1001) were positive for Salmonella. Multiplex PCR with three set primers was then applied to confirm serovar enteritidis 51.4% (35/68). Simple-PCR was then applied to detect spvA (Salmonella plasmid virulence), and spvB genes. Finally, multiplex PCR assay was carried out to simultaneously detect and identify invA and spvC genes. The presence of spvA,spvB and spvC in S. enteritidis was 88.6% for each gene. In the second stage of the study, thirty-three bovine (n = 13) and human (n = 20) S. enteritidis strains were isolated from the culture collection in the Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Iran. The analyses of the samples revealed that spvA, spvB, and spvC genes were present in 90% of S. enteritidis from human sources as compared to 100% in bovine sources. The study represents the first report in Iran about the genotypic diversity of spvA, spvB and spvC genes of S. enteritidis. Key words: Salmonella enteritidis, multiplex PCR, virulence genes.