Antimicrobial resistance phenotype and analyses of meca gene in staphylococcus aureus from cheese in Brazil

The widespread use of methicillin against bacterial infections, mainly in hospitals, led to the emergence of a resistance mechanism related to the presence and expression of the mecA gene, which encodes the protein PBP2a, resistant to penicillin/methicillin. Forty-two Staphylococcus aureus, previously isolated from Ricotta cheese sold in Brazil, were tested to antibiotic susceptibility and analyzed for the presence of mecA gene. Four isolates were resistant to oxacillin/methicillin, and to other antibiotics, including penicillin. Molecular characterization of the isolates revealed seven isolates carrying mecA gene. These results suggest that the resistance mechanism in these isolates is probably given by the expression of this gene, this may negatively regulated in isolates showed no resistance phenotype, since analysis showed that these genes do not have mutations that can explain the sensitive phenotype. Therefore, the food, particularly Ricotta cheese, are a potential way to spread strains of S. aureus carrying genes for resistance to antibiotics. Our results show that the presence of resistant strains in non-hospital environments merit special attention because the indiscriminate use of antibiotics by the population can lead to a positive selection of these strains, causing serious public health problems.