[Changes of antimicrobial resistance among nonfermenting gram-negative bacilli isolated from intensive care units from 1994 to 2001 in China]

Abstract

Objective: To investigate the antimicrobial resistance among nonfermenting gram-negative bacilli isolated from intensive care units (ICUs) during the past 7 years in China.

Methods: From 1994 to 2001, the minimal inhibitory concentrations (MICs) of imipenem and other ten antibiotics for 4450 strains of nosocomial nonfermenting bacteria isolated from the ICUs of 32 hospitals in China were determined by E test. WHONET-5 software was used to analyze the data.

Results: The most predominant pathogens were Pseudomonas aeruginosa (46.9%), Acinetobacter spp. (31.0%), and Stenotrophomonas maltophilia (9.2%). The susceptibility rates of these nonfermenting gram-negative bacilli to cefoperazone/sulbactam, imipenem, ceftazidime, piperacillin/tazobactam, amikacin, cefepime, and ciprofloxacin were 78.6%, 77.0%, 70.1%, 69.5%, 69.9%, 63.0%, and 59.1% respectively. Imipenem and cefoperazone/sulbactam were the most active agents against nonfermenting bacilli other than S.maltophilia and Burkholderia cepacia with susceptible rates 84.2% and 77.4% respectively. From 1994 to 2001, the activity of these 11 antibiotics against Pseudomonas aeruginosa decreased; the susceptibility rates of the nonfermenting gram-negative bacilli to imipenem, ceftazidime, amikacin, cefoperazone/sulbactam, cefepime, and piperacillin/tazobactam ranged from 70.0% to 83.0%. The susceptibility rate of Acinetobacter spp. to imipenem was 95.0% and remained unchanged for years. The susceptibility rate to cefoperazone/sulbactam came second, however, it was decreased from 88.0% in 1996 to 69.0% in 2001. The susceptibility rates to ceftazidime, cefepime, piperacillin/tazobactam, ticarcillin/clavulanic acid, gentamicin, and ciprofloxacin ranged from 45% to 58%. The susceptibility of Stenotrophomonas maltophilia was the highest to cefoperazone/sulbactam, ceftazidime, and ticarcillin/clavulanic acid (78% approximately 85%). Cefoperazone/sulbactam, piperacillin/tazobactam, and imipenem inhibited 80% of Alcaligenes spp. Only cefoperazone/sulbactam and piperacillin/tazobactam inhibited 70% of the strains of Flavobacterium spp; and 73% approximately 86% of Burkholderia cepacia were susceptible to cefoperazone/sulbactam, piperacillin/tazobactam, ceftazidime, and cefepime.

Conclusion: In recent 7 years, the antimicrobial resistance among nonfermenting gram-negative bacilli has increased in China. Antibiotics policy is urgently needed in order to delay the resistance development.