Molecular characterization and SCCmec typing in meticillin-resistant Staphylococcus aureus isolated from clinical samples

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is the main cause of hospital infection. The aim of present study was to investigate the molecular characteristics of Staphylococcus aureus (SA), to detect mecA gene, and to type SCCmec in the strains isolated from patients at Kashan Shahid Beheshti Hospital. Materials and Methods: This descriptive study was carried out on SA isolates (n=150) collected from the clinical samples at Kashan Shahid Beheshti Hospital, Iran during 2009. The identification of all tested isolates were confirmed using Gram's stain, coagulase, DNase and manitol salt agar. In addition, the genotypes of SCCmec in the MRSA isolates were determined by multiplex PCR. Results: Eighty seven (58%) out of 150 SA isolates were confirmed as MRSA harboring mecA gene detected by PCR. Thirty four out of 87 (39.1%) were HA-MRSA and the remainig 53 (60.9%) were CA-MRSA. The multiplex PCR assay for SCCmec complex of MRSA strains (n=87) showed that 3(3.4%) samples were SCCmec type I, 12(13.8%) SCCmec type II, 8(9.2)% SCCmec type IVb, 4(4.6%) SCCmec type IVd and 3(3.4%) SCCmec type V. Conclusion: More than 50% of SA strains were positive for mecA gene and more than 60% of them were CA-MRSA. Moreover, SCCmec type II was the predominant strain of the identified MRSA. Keywords: Methicillin-resistant Staphylococcus aureus, Bacterial typing, Molecular Typing,