Prevalence and Molecular Typing of Methicillin and Vancomycin-Resistant Staphylococcus aureus Strains Isolated from the Noses of Imam Hassan Hospital Workers in Bojnurd, Iran in the fall of 2021

Abstract

Introduction: Nosocomial infections are a global problem that has become a challenge in hospitals around the world since the 80s. One of the main sources of hospital infections is personnel. In this regard, the present study aimed to investigate the frequency, colonization rate, antibiotic resistance, and molecular types of Staphylococcus aureus in the personnel of key hospital departments, including emergency, infectious, Coronary Care Unit, and Intensive Care Unit Departments. Method: Nasal swab samples were collected from the personnel of the Emergency, Infectious, Coronary Care Unit, and Intensive Care Units Departments in the fall of 2021 and subsequently cultured. Confirmation of S. aureus strains was performed by biochemical tests, disk diffusion method, and agar screen test. Moreover, polymerase chain reaction for the evaluation of resistance genes was performed. Determination of agr group, determination of SCCmec type, and checking the presence of pvl, tst, and etc genes were also performed. Results: In total, 75 out of 214 staff nasal swab samples contained S. aureus. Prevalence of methicillin-resistant S. aureus was 65.3% confirmed by PCR test results. Based on the study of SCCmec types in MRSA strains, the most common type was SCCmecIII. Among the agr groups, type I was the most common, and in terms of the abundance of pvl, tsst, and etc genes, a relatively high prevalence was observed. Conclusion: Due to the increased level of personal and environmental health in hospitals, s. aureus colonizing the noses of personnel are more pathogenic and resistant due to the natural selection of strains. Therefore, they can cause more severe diseases following transmission to the patients.