Introduction: Staphylococcus aureus produces a wide variety of exotoxins that contribute to its ability to cause disease in hosts. Nearly all strains secrete a group of cytotoxins. The pyrogenic toxin superantigens (PTSAgs) are a group of exotoxins secreted by S. aureus strains. The family of PTSAgs presently includes TSST-1 and most of the staphylococcal enterotoxins. We aimed to study the profile of some virulence genes including: tsst-1, sec, hla and pvl in methicillin-resistant S. aureus by the PCR technique.

Materials & methods: A total Of 200 clinical isolates of S. aureus were isolated from patients and identified by conventional diagnostic tests. The MRSA isolates were detected by antibiotic susceptibility tests and mecA. Then, presence of some toxin genes in MRSA isolates was investigated by the Multiplex PCR technique.

Findings: The results showed that among the 200 isolates of S. aureus, 95 were confirmed as MRSA by screening with the oxacillin disc diffusion method. Also among the 95 MRSA isolates, all isolates were confirmed as methicillin-resistant by molecular methods. A total of 95 MRSA isolates, the frequency of the tsst-1, sec, hla and pvl genes were 60%, 3.15%, 93.68 and 4.21% respectively.  Additionally, 3 (3.15%) isolates were positive for tsst-1, hla and pvl genes.

Discussion & conclusion: S. aureus strains that produce toxins such as TSST-1, PVL, HLA, SEC are a serious threat to human health. The higher frequency of some toxin genes in this study may reflect the emergence of isolates containing these genes in Tehran hospitals.