Surveillance for antimicrobial resistance among clinical isolates of Gram-negative bacteria from intensive care unit patients in China, 1996 to 2002

The objective is to investigate the trend of antimicrobial resistance among nosocomial Gram-negative bacteria isolated from intensive care units in China. From 1996 to 2002, the minimum inhibitory concentrations (MICs) of 8 antibiotics for 10 585 isolates of Gram-negative bacteria from 19 hospitals in 7 central cities were determined by Etest. From 1996 to 2002, a marked decrease in the susceptibility of Pseudomonas aeruginosa to imipenem was noticed along the years (81-62%). Percentage of multidrug resistance of strains in P. aeruginosa obviously increased (11.5% in 1996, 20.5% in 2002). Imipenem kept active against Escherichia coli (99.2-100% susceptible), Acinetobacter spp. (97.6-93.5%), Klebsiella spp. (94.9-100%), Enterobacter spp. (89-96%). Resistance to cephalosporins, ciprofloxacin, and cefoperazone/sulbactam was observed, particularly among E. coli to ciprofloxacin (42-25%) and cefotaxime (78-54%) and Enterobacter spp. to ceftazidime (51-44%) and cefotaxime (50-37%). Piperacillin/tazobactam kept stable and active against P. aeruginosa, E. coli, and Klebsiella spp. (80%), with an increasing trend, but not good, in Enterobacter spp. (63-58%). Extended-spectrum β-lactamase-producing strains in E. coli (28.6-45.7%) and Klebsiella spp. (25.5-34.9%) increased during 2001-2002. There was no significant increase resistance in Enterobacteriaceae isolates and Acinetobacter spp. to imipenem, but it has obviously decreased activity in P. aeruginosa throughout the 7-year period in China. Resistance of tested Gram-negative bacteria to most comparator antimicrobials increased at different levels from 1996 to 2002 in China.