A total of 200 random samples of milk and milk products which included kareish cheese, yoghurt and ice-cream (50 for each) were examined microbiologically for the presence of S. aureus , their enterotoxigencity and their antibiotic sensitivity. S. aureus was isolated from 8/50 (16%) milk samples, 15/50 (30%) kareish cheese, 4/50 (8%) yoghurt and 11/50 (22%) ice-cream samples. All S. aureus isolates were showing clumping factor using kits for reliable latex agglutination test. The susceptibility of the isolates were determined for 12 antimicrobial drugs using disc diffusion assay. The majority were susceptible to ofloxacin and ampicillin + sulbactam (100%), vancomycin and tetracycline (94.7%), norfloxacin and sulphamethoxazole + trimethoprim (89.5%) , chloramphenicol (73.3%) but they were resistant to oxacillin and metronidazole (100%). Amplification of coagulase gene (coa) using uniplex PCR, staphylococcal enterotoxin genes (sea, seb, sec, sed and see) and methicillin-resistant S. aureus (mecA) gene using multiplex PCR revealed that, 11/11(100%) of the examined samples were positive for both coa and mecA genes. Sea produced by 5 (45.45%) strains , sec and sed produced by 4 (36.36%) strains and seb and see not produced by any strains. |
