Prophage Typing and SCCmec Typing of Methicillin Resistant Staphylococcus aureus Strains Isolated from Patients in Isfahan

Staphylococcus aureus is an important agent of nosocomial infections which has high potential to acquire resistance to different antibiotics. The aim of this study was to type and determine the antibiotic resistance patterns of methicillin resistant S. aureus strains isolated from patients in a hospital in Isfahan, Iran.
In this study a total of 117 S. aureus strains were collected during 6 months in 2015 form outpatients and hospitalized patients in a hospital in Isfahan. All isolates were identified at the species level using standard biochemical tests and also specific primers. Antibiotic susceptibility of S. aureus strains to 11 antibiotics was determined by the guidelines of CLSI, also presence of mecA gene among MRSA strains was tested. SCCmec typing and prophage typing of isolates was carried out using multiplex-PCR assay by specific primers.
All isolates were confirmed as S. aureus strains using phenotypic and genotypic methods. The highest antibiotic resistance was observed to erythromycin and followed by tetracycline and the lowest resistance was to vancomycin, linezolid and quinupristin-dalfopristin. Forty one percent of strains showed resistance to oxacillin and cefoxitin and also were positive for mecA gene, were confirmed as MRSA strains. Among MRSA strains, the highest rate of resistance was to erythromycin, ciprofloxacin, tetracycline, clindamycin, gentamicin and SXT, respectively. All MRSA strains harbored SCCmecc type III and classified as hospital acquired MRSA. Four different prophage types and 1 prophage pattern were found among isolates.
The prevalence of MRSA strains in this study was higher than other reports, and all isolates were classified as HA-MRSA strains. Vancomycin, linezolid and quinupristin-dalfopristin were the most effective antibiotics for treatment of infections caused by MRSA, in present study. High prevalence of antibiotic resistant clonal groups of MRSA strains which have potential to produce broad spectrum of virulence factors is a risk to public health.