RESUMEN
Background: The search for plasmid genes associated with virulence gene is of great epidemiological interest
Purpose of study: Demonstration the correlation between virulence gene either chromosomal or plasmid located in different locally isolated serovars and the pathogenicity of the isolated serovars through following stages
Study design: Isolation of the Salmonella from different sources [foecal swabs, blood and food poising], identification of isolates [cultural characters, biochemical and serotyping], pathogenicity of isolates in mice, plasmid profile in isolates and detection of virulence gene[s] in isolates using PCR
Main finding: The percent of Salmonella isolated from Egyptian population in different ages revealed that out of 515 examined samples 24 [4.66%] proved to be positive for salmonellosis. Children harbor Salmonella in a percent of 8% in blood samples and 5% from foecal swabs. At the same time samples from old aged population reached 6.6% in blood and 4% in foecal samples. Meanwhile the percentage of salmonellosis incidence in adult population was 4%. The results revealed that the most prevalent Salmonella serovars isolated were S. typhi 20%, S. typhimurium 20% and S. enteritidis 20% while S. paratyphi A, S. paratyphi B and S. paratyphi C in 16%, 12.5% and 8%, respectively. It can be observed that the percentage of non-typhoid Salmonella serovars as S. typhimurium and S. enteritidis were isolated in the same percentage as S. typhi which indicate the role of animals or their products in transmission of non typhoid Salmonella for this reason we performed isolation of Salmonella from milk, milk products, poultry products and beef products
Conclusion: The present study has confirmed the multifactorial elements responsible for pathogenesis of Salmonellae