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

Document Type : Research Paper


1 Department of Microbiology, Faculty of Biological Sciences, Falavarjan Branch, Islamic Azad University, Isfahan, Iran

2 Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

3 Department of Microbiology, Faculty of Biological Sciences, Falavarjan Branch, Islamic Azad University


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 the host is contracting. It was our aim in this study to detect and identify Sccmec typing of MRSA strains isolated from a teaching hospital 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 of Shariati Hospital in Isfahan between September 2018 and July 2020. Different types of SCCmec were investigated using the multiplex PCR method. Conventional PCR was performed to identify genes of virulence factors including pvl, tst, hlb, sak, eta, and etb. The MRSA strains detected included Sccmec type III in 96% of the cases and Sccmec type IV in the remaining 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. Ten toxin patterns were observed in the studied MRSA strains, and six 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, implementing an appropriate infection control policy is imperative to prevent the spread of MRSA types across a hospital.