Virulence genotypes of clinical SalmonellaSerovars from broilers in Egypt

Abstract

Introduction: Salmonella serovars are one of the primary foodborne pathogens. Poultry consumption is responsible for the majority of disease cases worldwide. The prevalence of virulence determinants among Salmonella serovars appears to be lacking in Egypt. Therefore, this study investigated the occurrence, antibiotic resistance patterns, and virulence gene profiling of Salmonella serovars in broilers. Methodology: Three hundred samples from broiler chickens were examined for the presence of Salmonella by standard microbiological techniques. All Salmonella isolates were tested for their sensitivity against ten antibiotics and subjected to virulence genotyping by polymerase chain reaction (PCR). Results: The overall isolation percentage of Salmonella was 17%. Seven different serovars were found, with the main one being Salmonella Typhimurium (52.94%). Salmonella isolates were sensitive to most of the tested antibiotics, but they exhibited absolute resistance against amoxicillin/clavulanic acid. Nine Salmonella strains (52.94%) were resistant to at least three antibiotics. Further PCR investigations into 17 Salmonella strains revealed different distribution patterns of eight virulence determinants among the isolates. The invA gene was the most prevalent one (100%), followed by hilA (88.24%), stn (58.82%), and fliC genes (52.94%), while each of sopB and pefA genes had a similar prevalence (41.18%), and sefC and spvC genes had the lowest prevalence (11.76 and 5.88%, respectively). PCR genotyping allowed grouping of Salmonella strains into ten genetic profiles. Conclusions: These results will help in understanding the spread of virulence genotypes and antibiotic resistance among Salmonella serovars in broilers.