Isolation and characterization of methicillin-resistant Staphylococcus aureus from livestock and poultry meat

Meat samples from sheep, bovine, camel and poultry were collected from Amman area and were processed and tested for the presence of methicillin (oxacillin) resistant Staphylococcus aureus (MRSA). Identity of S. aureus was ensured by Gram-staining and a battery of biochemical tests. From 1260 meat samples, 157 S, aureus positive isolates were identified. Of the 157 isolates, 30 were resistant to methicillin levels greater than 2 mu g/ml and only 15 were mecA-positive MRSA originating mainly from sheep and chicken. Subjecting the mecA-positive MRSA to antibiotic susceptibility testing revealed that all isolates were resistant to P-lactam antibiotics (ampicillin, penicillin, and oxacillin) and were sensitive to vancomycin, trimethoprim, chloramphenicol and cephalothin. Random amplified polymorphic DNA (RAPD) analysis of mecA-positive animal isolates generated six different patterns. Comparing these results with results of isolates of human origin of our laboratory there is some molecular epidemiological relatedness between both and could be a possible source of infections through consuming contaminated meat products, direct contact or meat processing.