nosocomial bacterial infections and their antimicrobial resistance patterns in university hospitals of hamedan, iran

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 eduâ­cational hospitals of hamadan, western iran. methods: during a 1-year period from april 2006 to march 2007, all patients with culâ­ture-proven nosocomial infections from educational hospitals in hamedan, westâ­ern iran were included. nosocomial infections were defined as a culture-proven infection, which occurred more than 48h after admission in the hospital. anâ­timicrobial susceptibility testing of isolated bacteria was performed by disc difâ­fusion method. results: a total of 170 cases of culture-proven nosocomial infections were diagâ­nosed. 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%). klebâ­siella pneumoniae , pseudomonas aeruginosa , and escherichia coli , were the most prevalent pathogens (32.7%, 22.9%, and 14.8% respectively). most enâ­terobacteriacea isolates were resistant to third generation cephalosporins. the resisâ­tant 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 ciproâ­floxacin. among s. aureus isolates, 80% were methicillin-resistant. conclusion: the patients in the icus are at a higher risk of nosocomial infecâ­tions. the high prevalence of antimicrobial resistance in the hospitals highlights the need of further infection control activities and surveillance programs.