High Frequency of Enterotoxin Encoding Genes of Staphylococcus Aureus Isolated from Food and Clinical Samples

Introduction and Objectives:Staphylococcus aureusis recognized as an important cause of food poisoning related to the consumption of raw, undercooked or mishandled foodsworldwide. Materials and Methods:A total of 90 individual meat samples and 200 clinical specimens were collected and investigated the frequency of S. aureus and classical enterotoxin genes. The samples were cultured on Baird Parker and Mannitol Salt agar and subjectedtoconfirmatory biochemical tests and molecular detection of femA, sea, seb, sec, sed and see genes. Results: A total of 31 (34.5%) meat samples and 81 (40.5%) clinical specimens were positive for the presence of S. aureus. These isolates were detected with a slightly higher frequency in clinical specimens than food samples (P> 0.05). Furthermore, the frequency of S. aureus in raw meat (23.4%) was higher than incooked meat samples (11.1%) (P< 0.05). Staphylococcal Enterotoxin (SE) genes were identified in 18 (58.1%) of 31 meat isolates and 42 (51.8%) of 81 clinical isolates. Frequency of SE genes (except see) in meat isolates was slightly higher than clinical isolates (P> 0.05). We found sea and seegenes with higher frequency than others in both meat and clinical samples. Furthermore, 55.5% of meat isolates and 38.1% of clinical isolates possessed more than one se gene. Conclusion: Detection of enterotoxigenic S. aureus in clinical and raw meat samples shows a probable risk for public health.Therefore, intensive and continuous monitoring of potentially pathogenic S. aureus is strongly recommended in order to evaluate the human health risk arising from food consumption.