Susceptibility of Klebsiella pneumoniae Isolates from Intra-Abdominal Infections and Molecular Characterization of Ertapenem-Resistant Isolates

Stephen P. Hawser, Samuel K. Bouchillon, Christine Lascols, Meredith Hackel, Daryl J. Hoban, Robert E. Badal, Neil Woodford, David M. Livermore

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47 Citations (Scopus)

Abstract

A total of 2,841 clinical isolates of Klebsiella pneumoniae from intra-abdominal infections worldwide were collected in the Study for Monitoring Antimicrobial Resistance Trends (SMART) during 2008 and 2009. Overall, 22.4% of isolates had extended-spectrum β-lactamases (ESBLs). The most active antibiotics among the 11 tested were imipenem, amikacin, and ertapenem, though even these, like all other comparators, were less consistently active against ESBL-positive isolates than against ESBL-negative isolates. Globally, 6.5% of isolates were ertapenem resistant based on the June 2010 clinical breakpoints published by the Clinical and Laboratory Standards Institute, with MICs of ≥1 μg/ml. Molecular characterization of 43 isolates with ertapenem MICs of ≥4 μg/ml showed that they variously produced CTX-M or SHV ESBLs combined with altered impermeability and/or had KPC (n = 28), OXA-48 (n = 3), or VIM (n = 1) carbapenemases. Further monitoring of ertapenem susceptibility and molecular characterization of ertapenem-resistant isolates are needed.
Original languageEnglish
Pages (from-to)3917-3921
Number of pages5
JournalAntimicrobial Agents and Chemotherapy
Volume55
Issue number8
DOIs
Publication statusPublished - Aug 2011

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