Objective:The study was designed to assess, isolate and characterize coagulase-positive S. aureus and its enterotoxins, in addition to their methicillin resistance contaminating the beef burger and hot dog sandwiches purchased from different fast-food restaurants distributed in Mansoura city.
Design: Observational study.
Procedures: A total of 100 meat (50 beef burger and 50 hot dog) sandwiches were bacteriologically and molecularly analyzed to isolate and characterize the contaminating coagulase-positive S. aureus and its enterotoxins, in addition to their methicillin resistance.
Results: S. aureus was found in 86% of overall tested samples, 90% in beef burger and 82% in hot dog sandwiches, in counts of 5.3×10 - 2.9×10⁴, 9.5×10 - 1.9×10⁴ and 1×10 - 3.8×10⁴ and mean counts of 3.9×10³, 3.5×10³ and 4.2×10³, respectively. Of the 106 confirmed coagulase-positive strains, 14 (13.2%) were enterotoxin producing strains and 47 (44.3%) of them carry the mecA gene confirmed their methicillin resistance. Regarding the microbiological quality of samples according to detected counts, 10%, 79% and 11% were acceptable, unsatisfactory, and potentially hazardous ready-to-eat meat sandwiches, respectively.
Conclusion and clinical relevance: The results indicated that tested ready-to-eat meat sandwiches were contaminated with enterotoxigenic and methicillin resistant S. aureus and represent a potential hazard to consumers; hence strict hygienic measures at fast-food restaurants are crucial.