Low frequency of ertapenem-resistant intra-abdominal isolates of Escherichia coli from Latin America: susceptibility, ESBL-occurrence, and molecular characterisation (SMART 2008-2009).

The Study for Monitoring Antimicrobial Resistance Trends is an ongoing multi-year surveillance study that tracks worldwide antimicrobial resistance trends among aerobic and facultatively anaerobic Gram-negative bacilli isolated from intra-abdominal infections. During 2008-2009, 1366 isolates of Escherichia coli were collected from 19 investigator sites in 11 Latin American countries. Of the 1366 isolates, 323 (23.6%) were extended spectrum beta-lactamase (ESBL)-positive. Overall, the most effective agents tested were imipenem, ertapenem, and amikacin with susceptibilities of ≥96%. Against ESBL-positive isolates, only imipenem and ertapenem exhibited susceptibility ≥90%. Based on the use of the new Clinical and Laboratory Standards Institute clinical breakpoints for ertapenem (resistance ≥1 µg/ml), resistance to ertapenem among all E. coli isolates was only 0.3% (4/1366) throughout the region, ranging from 0% in several countries up to 1.2% in Ecuador. Against ESBL-positive isolates only, resistance to ertapenem in Latin America overall was 0.9% (3/323), with a maximum of 9.1% (1/11) observed in Argentina.