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

IHMA Europe Sàrl, 1066 Epalinges, Switzerland.
Antimicrobial Agents and Chemotherapy (Impact Factor: 4.57). 07/2011; DOI: 10.1128/AAC.00070-11

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 - 2009. Overall, 22.4% of isolates had extended-spectrum beta-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 compared with ESBL-negative isolates. Globally, 6.5% of isolates were ertapenem-resistant based upon the June 2010 clinical breakpoints published by the Clinical and Laboratory Standards Institute, with MICs >/=1mug/ml. Molecular characterization of 43 isolates with ertapenem MICs >/= 4 mug/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 is needed.

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