RÉSUMÉ
ABSTRACT This study was conducted to determine the antimicrobial susceptibility patterns among common pathogens in the intensive care units (ICUs) of a university hospital in northwestern Iran. A retrospective study was done on laboratory records of patients with nosocomial infection who were admitted to five ICUs of Imam Reza Hospital during a 21-month period from March 2010 to January, 2012. A total number of 556 isolates from 328 patients were evaluated. The most common sites of infections included respiratory (51.7%), urinary (24.8%), and blood (10.4%). The most frequently isolated microorganisms were Enterobacter aerogenes (50.6%) followed by Escherichia coli (16.7%) and Pseudomonas aeruginosa (7.5%). Staphylococcus aureus was the most frequent pathogen among gram-positives (39.7%). The rate of methicillin-resistant Staphylococcus aureus (MRSA) was 87.5%. Multidrug-resistant (MDR) gram-negative bacteria were documented in 25.8% of Acinetobacter, 20% of Klebsiella, and 16.6% of Pseudomonas. The most active antimicrobials were vancomycin (93.5%) followed by amikacin (71.5%) and gentamicin (46%). The overall antibiotic susceptibility was as follows: 36% ciprofloxacin, 19% imipenem, 20% trimethoprim-sulfamethoxazole, 20.5% ceftazidime, and 12% ceftriaxone. Due to the high rate of antimicrobial resistance in the ICU setting, more surveillance and control of the use of antimicrobials is needed to combat infections.