Molecular identification of Methicillin-resistant staphylococcus aureus (MRSA) and Vancomycin- resistant staphylococcus aureus (VRSA) strains isolated from milk and milk products.

Document Type : Original Article


1 Bacteriology, Immunology and Mycology Department, Faculty of Veterinary Medicine, Benha University

2 Bacteriology Department, Animal Health Research Institute, Banha branch- Agriculture Research Center (ARC), Egypt.


Antimicrobial resistance is a global community health anxiety, particularly in developing countries and the indiscriminate use of antimicrobial agents is a major concern for the emergence of resistant bacterial pathogens. The following research was aimed to determine the in-vitro antimicrobial activity of previously isolated strains of Staphylococcus aureus from milk and milk products (23 strains) by the same author with molecular identification of their resistant genes. The results declared that all strains were completely resistant to Ampicillin (100%), followed by Amoxicillin and Erythromycin (86.9%) then Oxacillin (65.2%), while all strains show intermediate susceptibility to Vancomycin, Cefoxitin, Cefotaxime, and Norfloxacin. Gentamicin has the highest level of susceptibility (78.3%). Moreover, by cultivation of strains on ORSAB there were 15/23 MRSA strains, Also 5/23 strains showed resistant to Vancomycin and grow well in vancomycin screening agar. The genetic examination for the mecA gene and vanA gene done on seven strains (3 strains resistant to both oxacillin and vancomycin, 2 strains with intermediate resistance, and 2 strains sensitive to them) from different products. The results showed that all of them carried mecA gene while only two samples carried vanA gene.


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