The Survey on Prevalence and Risk Factors for Antibiotic-Resistant Staphylococcus Aureus Isolated from Samples in Kashan Hospitals

The Survey on Prevalence and Risk Factors for Antibiotic-Resistant Staphylococcus Aureus Isolated from Samples in Kashan Hospitals Moniri R۱, Shafiee M۲ ۱ Dept of Microbiology and Immunology, Kashan University of Medical Sciences, Kashan, Iran ۲ Pasteur Institute of Iran, Tehran, Iran Corresponding Authorchr('۳۹')s Address: Dept of Microbiology and Immunology, Kashan University of Medical Sciences, Kashan, Iran E-mail: [e-mail] Received: ۲۰ July, ۲۰۰۸ Accepted: ۱۷ Nov, ۲۰۰۸ Background and Objective: Methicillin-resistant Staphylococcus Aureus (MRSA) is a serious problem in hospitals. The purpose of this study was to determine the prevalence and related risk factors of methicillin resistance S. aureus isolated from clinical specimens in Kashan hospitals. Materials and Methods: This descriptive study was carried out on ۱۰۰ S.aureus strains isolated from patients admitted to Kashan hospitals in ۲۰۰۶- ۲۰۰۷. Strains were inoculated on blood agar containing ۵% sheep blood and ۷.۵% mannitol salt agar media, and were incubated at ۳۵°C for ۲۴ hours. The isolated S. aureus strains were identified using gram staining, catalase test, coagulase tube test, growth on chrome agar and the DNAse test. The antibiotic sensitivity test was determined by disk diffusion method. Variables including age, sex, previous hospitalization, duration of hospitalization, previous antibiotic therapy, and type of the disease, were recorded in questionarres. Data were analyzed statistically by the Chi-square and Fischer’s exact tests. Results: Penicillin and Ciprofloxacin revealed the highest and lowest resistance rates respectively (۹۹%, vs ۱۱ %). Meticillin resistance was ۲۲% and an intermediate resistance to Vancomycin was detected in ۷% of isolates. A significant correlation was established among the presence of resistant staphylococci with age of more than ۴۶ years old (P<۰.۰۴۰), previous hospitalization (P<۰.۰۰۰), hospitalization for more than ۱ week (P<۰.۰۰۰), previous antibiotic therapy (P<۰.۰۰۴), and administration of antibiotics for more than ۱ week (P<۰.۰۰۲). Conclusion: Awareness about the prevalence of antibiotic resistant S.aureus and identification of risk factors for infection with resistant isolates is essential to help clinicians, choosing appropriate antibiotic regimen.

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Key words: Resistant S. aureus , Methicillin , Risk factors , Kashan hospitals