Gram-negative bacilli isolated from patients in intensive care unit: prevalence and antibiotic susceptibility

The surveillance of 100 gram-negative bacilli that were recovered from patients in the intensive care unit (ICU) at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia showed that Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Enterobacter species, in this order, were the most frequently isolated organisms. The most common sites were respiratory tract (34%), wounds (24%), urinary tract (18%), and blood (11%). The resistance patterns towards different antimicrobial agents were determined by the minimal inhibitory concentration (MIC) using the E test. Imipenem, ciprofloxacin and amikacin were the most active agents against the isolates. Of the gram-negative isolates, 31% were resistant to at least two of the four major antibiotic groups (e.g. aminoglycosides, fluoroquinolones, third generation cephalosporins, and carbapenems), and 6% to three of the groups. Twenty-nine percent of the gram-negative bacilli were resistant to ceftazidime. Ceftazidime-resistant bacteria were frequently resistant to monobactams, piperacillin/tazobactam and gentamicin.