Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Microbiology

Staphylococcus aureus (S.aureus) is considered one of the most important pathogens to humans and animals. The emergence of methicillin-resistant S. aureus (MRSA) strains and other antimicrobial agents has become a major concern .316 samples (216 from bovine milk and 100 from nasal swabs of human) from Minia governorate were used in this study for isolation and identification of S.aureus from milk in healthy and diseased animals as well as from human nasal carriers, detection of the diversity between animal and human isolates by using phenotypic methods and amplification of certain genes; coa and mec A using PCR. all S. aureus isolates of the study (45) showed expression of mec A gene, although 96.77% of bovine isolates only was cefoxitin resistant by disk diffusion method so the detection of mec A gene is important for determination of MRSA. The 30 isolates of bovine milk showed 7 types of coa gene. The sizes of PCR amplicons obtained ranged from approximately 80 to approximately 640 bps. On the other hand the 14 isolates of human nasal swabs showed 6 types of coa gene, the size of PCR amplicons obtained after amplification of isolates from human nasal swabs ranged from approximately 80 to approximately 800 bps.it was noted that one isolate from bovine milk, identified as coagulase positive by tube coagulase test was found to be negative with PCR amplification of the gene, so the use of both phenotypic and molecular detection of S. aureus strains is very important

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