Prevalence, antibiogram, and expression of enterotoxin-coding genes of Staphylococcus aureus in bovine raw meat, liver, milk, and kariesh cheese

The objectives of the present study were firstly to investigate the prevalence of Staphylococcus aureus (S. aureus) in bovine meat, liver, raw milk, and kariesh cheese retailed in Egypt. Secondly, the antimicrobial resistance profiling of the recovered S. aureus isolates was examined. Thirdly, detection of the coding genes of S. aureus-enterotoxins (SE) including SEA, SEB, SEC, and SED was screened using PCR. The obtained results of the present study showed that S. aureus was isolated from retailed kariesh cheese, raw milk, raw liver, and raw meat at 80%, 70%, 65%, and 50%, respectively. Kariesh cheese had significantly the highest total S. aureus count (3.55 ± 0.19 log 10 cfu/g), followed by raw liver (3.08 ± 0.13 log 10 cfu/g), raw milk (3.04 ± 0.17 log 10 cfu/mL), and raw meat (2.39 ± 0.08 log 10 cfu/g), respectively. Additionally, 80%, 55%, 50%, and 25% of the examined kariesh cheese, raw liver, raw milk, and raw meat, respectively exceeded Egyptian limits of S. aureus in meat and dairies. Besides, S. aureus isolates showed clear multidrug resistance profiling. PCR testing of selected S. aureus isolates for harboring Staphylococcal enterotoxin-coding genes revealed that none of the tested genes were detected in isolates recovered from raw meat. However, some isolates recovered from raw milk, kariesh cheese, and raw liver harbored SEA, SEC, and SED. Therefore, strict hygienic measures should be adopted during handling, processing, and serving of such meat and dairies.