Genetic virulence of biofilm-forming Salmonella recovered from chicken sausages and nuggets

Aims: Salmonella is one of the most common foodborne illnesses worldwide. Poultry meat and products are the main sources of human infection. Therefore, the main objective of the current study was to assess the genetic virulence of biofilm-forming Salmonella isolated from chicken sausage and nuggets. Methodology and results: Isolation of Salmonella was carried out using XLD agar; suspected colonies were identified biochemically and then serotyped using the Kauffman-White scheme for detection of somatic (O) and flagellar (H) antigens. Congo red (CR) medium was used for the assessment of biofilm formation of the isolated strains. The invasion gene (invA), the heat-labile Salmonella enterotoxin gene (stn), plasmid-encoded fimbriae (pefA) genes, the protein effectors sopB, sopD and biofilm genes in six Salmonella isolates were investigated using mPCR, following QlAamp (R) DNA Mini Kit instructions and 1.5% agarose gel electrophoreses. Salmonella was detected in 12%, 8% and 4% of the examined frozen packaged raw chicken sausage, frozen packaged raw chicken nuggets and ready-to-eat sausage. The isolated strains were S. Typhimurium, S. Enteritidis, S. Essen and S. Montevideo. Moreover, mPCR indicated the presence of biofilm gene (csgD gene), stn, sopB and sopD virulence genes in all isolated strains (100%); however, pefA gene failed to be detected. Conclusion, significance and impact of study: The current findings showed that every Salmonella isolate examined was capable of creating biofilm at room temperature. As a result, these isolates are more likely to persist on abiotic surfaces, which raises the danger of cross-contamination and foodborne outbreaks.