PREVALENCE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS BY DISK DIFFUSION AND MOLECULAR METHODS IN ICU AND EMERGENCY SECTIONS IN ONE OF EDUCATIONAL HOSPITAL, TEHRAN

Methicillin-Resistant Staphylococcus aureus (MSRA) is one of the main causes of
serious infections in Iran and other countries. Treatment of these infections has become more difficult
because of resistance to most antibiotics. The aim of this study was to determine the incidence of
methicillin-resistance gene in S. aureus isolates and antibiotic susceptibility to oxacillin and other
antibiotics were performed by Disc Diffusion Agar (DDA).
Materials and Methods: This study was carried out on SA isolates (n=73) collected from the clinical
samples at during 2011 in ICU and Emeregency sections. All S. aureus isolates was identified after
performing by routine laboratory procedures including, Gram stain, catalase test, DNase production,
coagulase activity and mannitol salt fermentation. In this study used to identify Phenotypic by Disc
Diffusion Agar (DDA) and for identify genotypic two pairs of primers designed by AlleleID software
(version 6) on the basis of published DNA sequences of the S. aureus gene. Synthesis of primers was
carry out by Cinnagen Company, Iran. PCR reaction of mecA with designed primers was optimized
and incident of mecA was studied in clinical samples in ICU and Emergency sections.
Results: The PCR analysis of 73 S. aureus isolates originated from patients for mecA showed 65
(89%) cases were positive. But only 54 (74%) isolates were methicillin resistant when we used the
DDA method.
Conclusion: As a conclusion, the resistance to methicillin of S. aureus in Baqiyatallah hospitals has
reached to 89% and more than 95% of them were multidrug resistance