Prevalence of Enterotoxin A producing Methicillin Resistant Staphylococcus aureus Isolates in Tehran Hospitals

Staphylococcus aureus is known as community-acquired and nosocomial pathogen. Most of the isolates contain lysogenic phages and various virulence factors. The aim of the study was to analyze the antibiotic resistance pattern and detect the enterotoxin A gene among MRSA isolated from two hospitals in Tehran. Totally 94 isolates of methicillin resistant S. aureus were identified at the species level using specific primers. Susceptibility to seventeen antibiotics was determined using disc diffusion method and Minimum inhibitory concentration (MIC) of oxacillin and vancomycin in MRSA isolates were also detected using Etest. mecA and sea genes were detected using specific primers. Primers for identification of 6 classes of prophages were used in a Multiplex-PCR assay. The highest antibiotic resistance was observed to penicilli and followed by ciprofloxacin, erythromycin, kanamycin, amikacin, tobramycin, clindamycin and tetracycline. Five different prophage types were found in MRSA isolates and all MRSA isolates contained at least one prophage type. One hundred percent of the MRSA isolates contained sea and mecA genes. High prevalence of different classes of prophages, production of enterotoxin A and high resistance of MRSA isolates to first and second lines of treatments is a potential treat for public health.