Hamadan University of Medical Sciences Journal of Research in Health Sciences 2228-7795 10 1 2010 06 28 Nosocomial Bacterial Infections and Their Antimicrobial Resistance Patterns in University Hospitals of Hamedan, Iran 54 58 EN Seyyed Hamid Hashemi Mojgan Mamani Shirin Jamal-Omidi Amin Niayesh Journal Article 2011 06 29 Background: Nosocomial infections constitute a global health problem, leading to a high rate of morbidity and mortality. The aim of this study was to determine the frequency and antimicrobial resistance patterns of nosocomial infections in edu­cational hospitals of Hamadan, western Iran.Methods: During a 1-year period from April 2006 to March 2007, all patients with cul­ture-proven nosocomial infections from educational hospitals in Hamedan, west­ern Iran were included. Nosocomial infections were defined as a culture-proven infection, which occurred more than 48h after admission in the hospital. An­timicrobial susceptibility testing of isolated bacteria was performed by disc dif­fusion method. Results: A total of 170 cases of culture-proven nosocomial infections were diag­nosed. Most cases were in intensive care units (ICUs) (57.4%). The common sites of infection were lower respiratory tract (51.8%) and urinary tract (31.9%). Kleb­siella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli, were the most prevalent pathogens (32.7%, 22.9%, and 14.8% respectively). Most en­terobacteriacea isolates were resistant to third generation cephalosporins. The resis­tant rates to ceftriaxone were 75.5% for K. pneumoniae, and 76% for E. coli. Among P. aeruginosa isolates, 26.5% were resistant to ceftazidim, and 36% to cipro­floxacin. Among S. aureus isolates, 80% were methicillin-resistant. Conclusion: The patients in the ICUs are at a higher risk of nosocomial infec­tions. The high prevalence of antimicrobial resistance in the hospitals highlights the need of further infection control activities and surveillance programs.