In vitro susceptibilities of aerobic and facultative anaerobic Gram-negative bacilli isolated from patients with intra-abdominal infections at a medical center in Taiwan: results of the Study for Monitoring Antimicrobial Resistance Trends (SMART) 2002-200
Wei-Yu Chen, Tsrang-Neng Jang, Chien-Hsien Huang, Po-Ren Hsueh
J Microbiol Immunol Infect. 2009;42:317-323.
Received: March 1, 2009 Revised: July 22, 2008 Accepted: August 4, 2008
Po-Ren Hsueh, Department of Laboratory Medicine, and Internal Medicine, National Taiwan University Hospital, National Taiwan University Hospital College of Medicine, No. 7 Chung-Shan South Rd., Taipei 100, Taiwan.
Background and purpose:
The Study for Monitoring Antimicrobial Resistance Trends (SMART) was initiated to monitor the in vitro antimicrobial susceptibility of aerobic and facultative anaerobic Gram-negative bacilli (GNB) isolated from patients with intra-abdominal infections (IAI). This report summarizes the SMART data from 1 of the study centers from 2002 to 2006.
492 Gram-negative isolates were collected from 482 patients with IAI. Susceptibilities of these isolates to 12 antimicrobial agents were determined using the broth microdilution method.
Enterobacteriaceae comprised 68.3% of the isolates (n=336). The 4 main species were Klebsiella spp. (n=129; 26.2%), Escherichia coli (n=122; 24.8%), Enterobacter spp. (n=36; 7.3%), and Aeromonas hydrophila (35; 7.1%). The commonest glucose ono-fermentative GNB were Acinetobacter baumannii (n=46; 9.3%) and Pseudomonas aeruginosa (n=35; 7.1%). Extended-spectrum beta-lactamase (ESBL) production was detected in 70 Enterobacteriaceae isolates (70/336; 21%). The ESBL phenotype was exhibited by 23% of Klebsiella pneumoniae, 26% of E. coli, and 19% of Enterobacter spp. The hightest rate of ESBL production was found in 2005 for E. coli (38%) and in 2003 for Klebsiella spp. (38%) and Enterobacter spp. (40%).The incidence of ESBL-producing isolates declined in 2005 and 2006. Low susceptibility rates of E. coli isolates to ciprofloxacin (58%) and levofloxain (64%) were noted. Ertapenem (99%), imipenem (99%), and amikacin (94%) were the most potent agents against enterobacteriaceae spp.
Continuous surveillance is crucial to monitor the trend of antimicrobial resistance paterns among GNB isolated from IAI.