Iranian Journal of Medical Microbiology

Background & Aims: The Staphylococcal cassette chromosome mec (SCCmec) is a mobile genetic element that acquires the mecA gene. The five main categories of SCCmec components in methicillin-resistant Staphylococcus aureus (MRSA) are I-V. The majority of MRSA strains acquired in hospitals (HA-MRSA) have SCCmec types I, II, III, while strains acquired in the community (CA-MRSA) have SCCmec types IV or V. This study aims to determine the presence of SCCmec types, subtypes in clinical MRSA isolates and their antibiotic sensitivity pattern.
Methods: MRSA isolates identification and antibiotic sensitivity were performed using phenotypic and automated methods. Single-target PCR was performed for the presence of the mecA gene to confirm the MRSA. Multiplex PCR was performed to identify the types and subtypes of SCCmec.
Results: A total of 35 MRSA isolates were confirmed using single-target PCR for the mecA gene. Multiplex PCR showed SCCmec type IVd (63%), the most commonly identified type, followed by SCCmec type V (23%). 14%, isolates remained non-typeable. SCCmec type I-III/IVa-c was not detected in any of these isolates. Type IVd strains showed more than 50% resistance to Erythromycin, Cotrimoxazole, Gentamicin and Clindamycin. Type V strains showed more resistance to Gentamicin and Erythromycin.
Conclusion: MRSA SCCmec typing is a useful method to know the epidemiology of various SCCmec types and subtypes circulating in hospitals and communities, and helps to understand the changing trend, if any. But the use of other typing methods in combination with SCCmec typing may help further differentiate various clones circulating in these types and identify novel types.