International Journal of Medical Laboratory

Background and Aims: The aim of present study was to investigate the molecular characteristic of Staphylococcus aureus to detect mec A gene and to type SCCmec in strain isolated from healthy worker at Larestan Hospital.

Material and Methods: This study was carried out from the 250 nasal swab healthy worker  at Larestan hospital. Multiplex polymerase chain reaction for mecA gene was performed in all samples. Also, agar screen plate with oxacillin was carried out using CLSI guidelines. The two methods were then compared.

Results: Of 250 samples, 37 (14.8%) samples are Staphylococcus aureus, 28 (75.7%) of samples were confirmed at Methicillin-resistant Staphylococcus aureus (MRSA) harboring mec A gene detected by Multiplex polymerase chain reaction (PCR) and 9 (24.3%) negative mec A. Sixteen of 28 (57.1%) were HA-MRSA and the remaining 12 (42.8%) were CA-MRSA. The Multiplex PCR assay for SCCmec complex of MRSA strains showed that 9 (32.1%) samples were SCCmec type I, 8 (28.6%) SCCmec type IVb, 5 (17.9%) SCCmec type II, 4 (14.3%) SCCmec type V and 2 (7.1%) SCCmec type III. Agar screen plate with oxacillin was found in all the 28 MRSA samples to harbor mecA gene and all was resistant.

Conclusion: Our results illustrated that more than 70% of staph aureus strains were positive for mec A gene and more than 50% of them were HA-MRSA. In comparison to other methods, PCR and Agar screen method more sensitivity determines MRSA isolates. However, PCR was identified as the ideal method for detecting MRSA strains.