Molecular Typing of Staphylococcal Cassette Chromosome Mec (SCCmec) in Methicillin-Resistant Staphylococcus aureus Isolated from Clinical Samples

Methicillin-resistant Staphylococcus aureus has been considered as one of the pathogens involved in nosocomial infections. The study of drug resistance and typing of this bacterium is an effective measure to prevent and spread it. This study aimed to detect the mecA gene as well as SCCmec typing of Staphylococcus aureus isolates isolated from clinical specimens.

After collection, 308 clinical specimens were identified as Staphylococcus aureus isolates by confirmatory tests. Drug susceptibility was assessed by agar screen method and after DNA extraction by PCR, strains with mecA gene were identified and SCCmec typing was performed by multiplex PCR.

Staphylococcus aureus isolates showed resistance to methicillin in the agar screen method, but in the PCR method, 73% of them showed mecA positive gene. The results showed that these six strains were resistant to methicillin in the agar screen test but did not have the mecA gene in the PCR method. The highest percentage of samples belonged to SCCmec IV type (37%) and then belonged to SCCmecIII (31%).

More than 73% of Staphylococcus aureus strains had the mecA gene and 56% of them were registered as hospital-acquired strains.