In vitro susceptibilities of aerobic and facultatively anaerobic Gram-negative bacilli isolated from patients with intra-abdominal infections worldwide: 2004 results from SMART (Study for Monitoring Antimicrobial Resistance Trends).

OBJECTIVES

SMART (Study for Monitoring Antimicrobial Resistance Trends) is an ongoing study to monitor worldwide antimicrobial resistance trends among aerobic and facultatively anaerobic Gram-negative bacilli (GNB) isolated from intra-abdominal infections. This 2004 report summarizes the most recently completed annual data from SMART.

METHODS

During 2004, 81 medical centres from 28 countries in five global regions collected intra-abdominal GNB for antimicrobial susceptibility testing using broth microdilution according to the Clinical and Laboratory Standards Institute guidelines.

RESULTS

A total of 6156 unique aerobic and facultatively anaerobic GNB were isolated from intra-abdominal infections. Enterobacteriaceae composed 86% of the total isolates. Among the 12 antimicrobial agents tested, the carbapenems and amikacin were the most consistently active against the Enterobacteriaceae. Escherichia coli was the most commonly isolated species (48%), and the susceptibility rate to the quinolones was lowest in Asia/Pacific and Latin America. Extended-spectrum beta-lactamases (ESBLs) were detected phenotypically in 10% of E. coli, 17% of Klebsiella spp. and 22% of Enterobacter spp. worldwide, representing a slight increase over the two previous years. ESBL producers typically had a more antibiotic-resistant profile than non-ESBL producers but were usually susceptible to the carbapenems.

CONCLUSIONS

Antimicrobial resistance among GNB isolated from intra-abdominal infections continued to be a problem worldwide in 2004, with the highest rates of resistance overall in the Asia/Pacific region. The carbapenems and amikacin were the most consistently active agents in vitro against Enterobacteriaceae isolated from intra-abdominal infections worldwide.