In vitro susceptibilities of aerobic and facultative Gram-negative bacilli isolated from patients with intra-abdominal infections worldwide: the 2003 Study for Monitoring Antimicrobial Resistance Trends (SMART).

OBJECTIVES

The SMART (Study for Monitoring Antimicrobial Resistance Trends) surveillance programme was begun in 2002 to monitor antimicrobial resistance trends among aerobic and facultative Gram-negative bacilli (GNB) isolated from intra-abdominal infections worldwide.

METHODS

In 2003, 74 medical centres from 23 countries collected isolates for testing. Antimicrobial susceptibility testing was performed using broth microdilution according to the NCCLS guidelines for MIC testing.

RESULTS

A total of 5658 aerobic and facultative GNB were isolated from intra-abdominal infections. Enterobacteriaceae composed 84% of the total isolates. Among the agents tested, the carbapenems were the most consistently active against the Enterobacteriaceae. E. coli was the most common isolate (46%), and the susceptibility rate to the quinolone (70-90% susceptible), cephalosporin (80-97% susceptible), aminoglycoside (77-100% susceptible) and carbapenem (99-100% susceptible) agents tested varied among geographic regions, with isolates from the Asia/Pacific region generally being the most resistant. Extended-spectrum beta-lactamases (ESBLs) were detected phenotypically in 9% of E. coli, 14% of Klebsiella spp., and 14% of Enterobacter spp. worldwide. ESBL producers generally had a more antibiotic-resistant profile than non-ESBL producers.

CONCLUSIONS

Antimicrobial resistance among GNB isolated from intra-abdominal infections is a problem worldwide, especially in the Asia/Pacific region. The carbapenems ertapenem, meropenem and imipenem are highly active in vitro against Enterobacteriaceae isolated from intra-abdominal sites, including organisms that produce ESBLs.