Phenotypic detection of methicillin-resistant Staphylococcus aureus in some cheese varieties

Document Type : Original Article


1 Veterinary officer At Egyptian armed forces

2 Food control Dept., Fac. Vet. Med., Menoufiya University

3 Animal health research institute, ARC

4 Food Hygiene and control Department, Faculty of Veterinary Medicine, Benha University.


Hundred and eighty random cheese samples, includes varities of cheese, soft (kareish and white); hard (Roomy); processed (Flamingo), beside machine and hand swabs were collected from different supermarkets (30 of each), at Qalubiya governorate, Egypt to investigate the incidence of Staphylococci with especial reference to MRSA strains. The results revealed that the mean value of Staphylococci and S. aureus counts (cfu/g) in kareish cheese samples were 3.16×105 and 6.57×104, respectively; for white cheese samples were 7.60×104 and 5.12×104, respectively; for Roomy cheese samples were 5.79×104 and 3.38×104, respectively; for Flamingo cheese samples were 2.96×104 and 1.05×104, respectively; for machine swab samples were 1.02×104 and 1.48×103, respectively and for hand swab samples were 1.43×104 and 3.71×103 (CFU/ml), respectively. A total of 118/180 (65.5%) isolates of staphylococci species, includes 55 S. aureus (30.6%). All 55 isolated S. aureus strains were coagulase positive while, other isolated staphylococcal strains (63) were coagulase negative. The isolated S. aureus was highly resistant for methicillin followed by oxacillin; nalidixic acid; ampicillin; oxytetracycline; cefotaxime and streptomycin. Meanwhile, it was highly sensitive to vancomycin followed by norfloxacin; gentamicin; meropenem and ciprofloxacin. A total of 49 S. aureus strains out of 55 ones were grown well on ORSAB media (they were MRSA strains). Finally, S. aureus and MRSA strains were found in the examined cheese sampels sold in markets at Qalubuiya governorate; beside that MRSA strains were detected that threats the consumer's health.


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