Surveillance of antimicrobial susceptibility among bacterial isolates from intensive care unit patients of a tertiary-care university hospital in Iran: 2006-2009

Abstract

Background: This study was conducted to determine the antimicrobial susceptibility patterns among common pathogens in the intensive care unit (ICU) of a university hospital in Iran between 2006 and 2009.

Methods: The isolates cultured in appropriate media and antimicrobial susceptibility were determined by disk diffusion tests according to the guidelines of the Clinical and Laboratory Standards Institute.

Results: A total of 606 isolates were recovered from respiratory (70.63%), urine (20.13%), blood (4.95%) and wound (1.82%) specimens of 456 patients. The most common isolates were Acinetobacter baumannii (22.4%), Pseudomonas aeruginosa (20.6%), Staphylococcus aureus (11.1%), Escherichia coli (8.3%) and Klebsiella pneumoniae (4.8%). Less than 7% of A. baumannii isolates were susceptible to aminoglycosides, ceftazidime, cefotaxime, imipenem, cefepime and ciprofloxacin. None was susceptible to piperacillin and piperacillin-tazobactam. The susceptibility rates of P. aeruginosa to ciprofloxacin, gentamicin and piperacillin-tazobactam were 13.6, 17.4 and 33.3%, respectively. Methicillin-resistant S. aureus made up 96.2% of S. aureus isolates and was 100% susceptible to vancomycin and 51.9% susceptible to trimethoprim-sulfamethoxazole.

Conclusion: Due to the high antimicrobial resistance in the ICU, we must focus on both a wiser use of antimicrobials and the prevention of infection.