Are susceptibility tests enough, or should laboratories still seek ESBLs and carbapenemases directly?

Livermore, David M., Andrews, Jenny M., Hawkey, Peter M., Ho, Pak-Leung, Keness, Yoram, Doi, Yohei, Paterson, David and Woodford, Neil (2012) Are susceptibility tests enough, or should laboratories still seek ESBLs and carbapenemases directly?. Journal of Antimicrobial Chemotherapy, 67 7: 1569-1577. doi:10.1093/jac/dks088

Author Livermore, David M.
Andrews, Jenny M.
Hawkey, Peter M.
Ho, Pak-Leung
Keness, Yoram
Doi, Yohei
Paterson, David
Woodford, Neil
Title Are susceptibility tests enough, or should laboratories still seek ESBLs and carbapenemases directly?
Journal name Journal of Antimicrobial Chemotherapy   Check publisher's open access policy
ISSN 0305-7453
Publication date 2012-07
Sub-type Article (original research)
DOI 10.1093/jac/dks088
Volume 67
Issue 7
Start page 1569
End page 1577
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Collection year 2013
Language eng
Abstract Recent EUCAST advice asserts that, with low breakpoints, susceptibility results for cephalosporins and carbapenems can be reported 'as found', even for strains with extended-spectrum β-lactamases (ESBLs) and carbapenemases. The CLSI has similar advice, but with higher ceftazidime and cefepime breakpoints than those of EUCAST. Pharmacodynamic and animal data are used to support these views, along with some analysis of clinical case series. We contend that such advice is misguided on three counts. First, whilst there are cases on record where cephalosporins and carbapenems have proved effective against infections due to low-MIC ESBL producers and low-MIC carbapenemase producers, respectively, there are similar numbers of cases where such therapy has failed. Second, routine susceptibility testing is less precise than in research analyses, meaning that ESBL and carbapenemase producers with 'real' MICs of 1-8 mg/L will oscillate between susceptibility categories according to who tests them and how. Third, although EUCAST continues to advocate ESBL and carbapenemase detection for epidemiological purposes, the likely consequence of not seeking these enzymes for treatment purposes is that some laboratories will not seek them at all, leading to a loss of critical infection control information. In short, it is prudent to continue to seek ESBLs and carbapenemases directly and, where they are found, generally to avoid substrate drugs as therapy.
Keyword Ceftazidime
CTX-M -lactamases
KPC -lactamases
European Committee on Antimicrobial Susceptibility Testing
Clinical Laboratory Standards Institute
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes First published online: 29 March 2012. Article number dks088

Document type: Journal Article
Sub-type: Article (original research)
Collections: UQ Centre for Clinical Research Publications
Official 2013 Collection
School of Medicine Publications
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