Evaluation of the Prevalence of mec A Gene in Staphylococcus aureus Strains Isolated from Clinical Specimens of Hospitals and Treatment Centers

Background and Objective: Staphylococcus aureus bacteria is a common cause of hospital infections. Resistant strains of this bacterium are a major pathogen in causing disease and death in Iran and the world. Therefore, the aim of this study was to investigate the prevalence of mecA methicillin resistance gene and determine antibiotic resistance patterns in S. aureus strains isolated from clinical specimens. Materials and Methods: In this descriptive cross-sectional study, 100 strains of S.aureus from Tabriz hospitals and treatment centers were collected. The isolates were identified by standard laboratory methods and cultured in a specific Culture Media. The identification of MRSA strains was done by phenotypic and molecular methods. The PCR method was used to determine the frequency of mecA gene. In order to evaluate antibiotic susceptibility patterns of strains, a disk diffusion method based on CLSI protocol was performed. Results: Of the 100 samples examined, 75 samples of methicillin-resistant S.aureus were found. The phenotypic evaluation of the antibiotic resistance pattern of methicillin-resistant S.aureus showed that the highest resistance to penicillin antibiotics was 100% and Co-Amoxiclav was 91.66%. Molecular examination revealed the presence of 68% of the mecA gene in isolates. Conclusion: In this study the prevalence of the antibiotic resistance pattern of methicillin-resistant S.aureu was high. This recent study suggests increased resistance to methicillin-resistant S.aureus in compare to other antibiotics, which is a serious warning for the treatment of S.aureus infection in the region.  Therefore, in order to prevent the increase of resistance to other antibiotics, it is essential to avoid the administration of uncontrolled and unnecessary antibiotics.