Antimicrobial resistance pattern of Gram-negative bacilli of nosocomial origin at 2 university hospitals in Iran

The purpose of this study was to investigate the antimicrobial resistance pattern among common Gram-negative bacilli isolated from patients with nosocomial infection. A total of 200 samples of common Gram-negative bacilli (Klebsiella, Pseudomonas, Acinetobacter, and Escherichia coli) were collected from 2 university hospitals in Iran during a 1.5-year period from June 2004 to December 2005. All samples were examined for the antimicrobial activity of imipenem, cefepime, ciprofloxacin, ceftriaxone, and ceftazidime using E-test methods. The most frequent pathogens were Klebsiella spp. (38.5%) followed by Pseudomonas aeruginosa (28.5%), Acinetobacter spp. (20.5%), and E. coli (12.5%). The most active antibiotic was imipenem (84%). The susceptibility of the studied microorganisms was 25% for cefepime, 24% for ciprofloxacin, 20.5% for ceftazidime, and 11.8% for ceftriaxone. The susceptibility rates of Klebsiella to imipenem, cefepime, ciprofloxacin, ceftazidime, and ceftriaxone were 90.9%, 20.8%, 18.2%, 10.4%, and 5.2%, respectively. Likewise, these rates were 88%, 19%, 17%, 21%, and 21% for E. coli. Among Acinetobacter spp., the susceptibility rates were 77% for imipenem and 21% for ciprofloxacin. Among Pseudomonas, the rates were 75% for imipenem and 39% for ciprofloxacin. The antibiotics resistance among Gram-negative bacilli was widespread, so an antibiotic policy is urgently needed to delay the resistance development.