Background: Since 2002, the worldwide Study for Monitoring Antimicrobial Resistance Trends
(SMART) has tracked resistance patterns among aerobic and facultative gram-negative bacilli
isolated from patients with intra-abdominal infections. Escherichia coli has been by far the
most frequently isolated species.
Methods: Antimicrobial susceptibilities for consecutive non-duplicate isolates of aerobic
and facultative gram-negative bacilli recovered from intra-abdominal infections were determined
by standard broth microdilution techniques. A subanalysis was performed for E. coli
isolates from the first three years of the study.
Results: A total of 7,002 E. coli isolates were recovered, most commonly from the peritoneal
cavity followed by the biliary tract. Susceptibility rates to the 12 antimicrobial agents tested
differed among geographic regions, with isolates from Asia/Pacific generally having the highest
resistance rates. Overall, extended-spectrum beta-lactamase (ESBL)-producers had a more
antibiotic-resistant profile than non-ESBL-producers but usually were susceptible to the carbapenems
and amikacin. Community-acquired E. coli strains comprised slightly more than
one-half of the isolates and were susceptible to the agents tested more frequently than were
hospital-acquired E. coli.
Conclusions: The prevalence of antimicrobial resistance among E. coli isolated from intraabdominal
infections is not inconsequential, especially in the Asia/Pacific region. The carbapenems
and amikacin were consistently active in vitro against E. coli isolates worldwide,
including ESBL-producers.
