Carbapenem therapy for bacteremia due to extended-spectrum-β-lactamase-producing Escherichia coli or Klebsiella pneumoniae: implications of ertapenem susceptibility.

Abstract

A retrospective study was conducted at two medical centers in Taiwan to evaluate the clinical characteristics, outcomes, and risk factors for mortality among patients treated with a carbapenem for bacteremia caused by extended-spectrum-beta-lactamase (ESBL)-producing organisms. A total of 251 patients with bacteremia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates treated by a carbapenem were identified. Among these ESBL-producing isolates, rates of susceptibility to ertapenem (MICs ≤ 0.25 μg/ml) were 83.8% and 76.4%, respectively; those to meropenem were 100% and 99.3%, respectively; and those to imipenem were 100% and 97.9%, respectively. There were no significant differences in the critical illness rate (P = 0.1) or sepsis-related mortality rate (P = 0.2) for patients with bacteremia caused by ESBL-producing K. pneumoniae (140 isolates, 55.8%) and E. coli (111 isolates, 44.2%). Multivariate analysis of variables related to sepsis-related mortality revealed that the presence of severe sepsis (odds ratio [OR], 15.9; 95% confidence interval [CI], 5.84 to 43.34; P < 0.001), hospital-onset bacteremia (OR, 4.65; 95% CI, 1.42 to 15.24; P = 0.01), and ertapenem-nonsusceptible isolates (OR, 5.12; 95% CI, 2.04 to 12.88; P = 0.001) were independent risk factors. The patients receiving inappropriate therapy had a higher sepsis-related mortality than those with appropriate therapy (P = 0.002), irrespective of ertapenem, imipenem, or meropenem therapy. Infections due to the ertapenem-susceptible isolates (MICs ≤ 0.25 μg/ml) were associated with a more favorable outcome than those due to ertapenem-nonsusceptible isolates (MICs > 0.25 μg/ml), if treated by a carbapenem. However, the mortality for patients with bacteremic episodes due to isolates with MICs of ≤ 0.5 μg/ml was similar to the mortality for those whose isolates had MICs of >0.5 μg/ml (P = 0.8). Such a finding supports the rationale of the current CLSI 2011 criteria for carbapenems for Enterobacteriaceae.

• Authors: Nan-Yao Lee, Ching-Chi Lee, Wei-Han Huang, Ko-Chung Tsui, Po-Ren Hsueh, Wen-Chien Ko
• Journal: Antimicrobial agents and chemotherapy (Antimicrob Agents Chemother) Vol. 56 Issue 6 Pg. 2888-93 (Jun 2012) ISSN: 1098-6596 [Electronic] United States
• PMID: 22430969 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Thienamycins
• beta-Lactams
• Imipenem
• Meropenem
• Ertapenem

Topics

• Adult
• Bacteremia (drug therapy, microbiology)
• Ertapenem
• Escherichia coli (drug effects, pathogenicity)
• Escherichia coli Infections (drug therapy, microbiology)
• Female
• Humans
• Imipenem (therapeutic use)
• Klebsiella Infections (drug therapy, microbiology)
• Klebsiella pneumoniae (drug effects, pathogenicity)
• Male
• Meropenem
• Microbial Sensitivity Tests
• Retrospective Studies
• Thienamycins (therapeutic use)
• Young Adult
• beta-Lactams (therapeutic use)