Molecular typing and investigation of virulence factors of methicillin-resistant Staphylococcus aureus strains isolated from patients hospitalized in an Isfahan teaching hospital

The increase in the incidence of Staphylococcus aureus infections in nosocomial settings each year is a significant concern for the public health sector, as it is one of the most common nosocomial infections. Furthermore, it produces a variety of toxins that aggravate the disease that is being contracted by the host. It was our aim in this study to detect and identify Sccmec typing of MRSA strains isolated from one of the teaching hospitals in Isfahan, Iran, as part of a research project. The presence of different virulence factors was also investigated. To conduct this study, 50 strains were collected from different samples from a teaching hospital in Isfahan for 20 months. Different types of SCCmec were investigated by using multiplex PCR method. Conventional PCR was performed to identify genes of virulence factors including pvl, tst, hlb, sak, eta, and etb. MRSA strains were detected as Sccmec type III in 96% of the cases, and Sccmec type IV in 4% of the cases. The frequencies of hlb, sak , eta, tst, pvl and etb genes in clinical isolates of MRSA were 82%, 50%, 42%, 6%, 4% and 0%, respectively. 10 toxin patterns were observed in the studied MRSA strains. 6 MRSA strains did not have the studied toxins gene. Considering the production of different toxins in MRSA strains and the circulation of one type in the studied hospital it is imperative that an appropriate infection control policy be implemented in order to prevent the spread of MRSA types across a hospital.