Surveillance of antimicrobial resistance among gram-negative bacilli from intensive care unit

Objective To investigate the antimicrobial resistance among gram-negative bacilli from intensive care unit(ICU) for rational use of antimicrobials.Methods From January 2003 to December 2004,antimicrobial susceptibility testing was done on gram-negative bacilli isolated from ICU in our hospital by Kirby-Bauer method.The results were interpreted according to NCCLS 2003.Results Out of 245 isolates,65.3% were non-fermentative bacilli(Acinetobacter spp.48.2% and Pseudomonas aeruginosa 11.0%).About 74.5% of the strains were isolated from sputum.The susceptibility rate of gramnegative bacilli to imipenem was the highest(93.9%).Imipenem showed good antimicrobial activity against gram-negative bacilli except Stenotrophomonas maltophilia.The susceptibility rate of gram-negative bacilli to ceftazidime,cefoperazone-sulbactam,cefepime,amikacin and piperacillin-tazobactam ranged from 44% to 68%,but they were highly resistant to other antimicrobial agents.The susceptibility rates of S.maltophilia to ceftazidime and TMP-SMZ were 73.3%.About 26.3% of E.coli and 32.3% of Klebsiella spp.isolates were extended-spectrum β-lactamases(ESBLs) producers.The resistance rate of ESBL producing strains to most antibiotics was much higher than those of non-ESBLs producing strains.No imipenem-resistant isolate was found.Conclusions In ICU,most gram-negative bacilli are non-fermenters.Imipenem remains highly active against gram-negative bacilli except S. maltophilia.Other antibiotics are less active against non-fermentative bacilli.