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Rapid EUCAST disc diffusion testing of MDR Escherichia coli and Klebsiella pneumoniae: inhibition zones for extended-spectrum cephalosporins can be reliably read after 6 h of incubation.
- Source :
-
The Journal of antimicrobial chemotherapy [J Antimicrob Chemother] 2017 Apr 01; Vol. 72 (4), pp. 1094-1102. - Publication Year :
- 2017
-
Abstract
- Objectives: The need for rapid antibiotic susceptibility testing increases with escalating levels of antimicrobial resistance in Enterobacteriaceae. Our objective was to evaluate the accuracy of reading EUCAST disc diffusion, ROSCO ESBL and carbapenemase detection kits and the Mast Carbapenemase Activity Test (CAT-ID) disc, after 6 h of incubation.<br />Methods: We used a collection of 128 isolates of Escherichia coli and Klebsiella pneumoniae with a wide variety of resistance mechanisms. Inhibition zones read from digital photo images with the BD Kiestra™ Total Lab Automation System after 6 h of incubation were compared with standard reading, after 18 h, of the same Mueller-Hinton agar plates.<br />Results: For WT isolates, zones were generally smaller at 6 h than at 18 h. Cefotaxime had excellent categorical agreement of 99%, despite the high number of challenge isolates. However, for some other antimicrobials, hetero-resistant subpopulations were commonly invisible at 6 h, which resulted in an unacceptable number of errors when using standard EUCAST breakpoints. Accurate ESBL detection was possible at 6 h for isolates lacking other β-lactamases. Carbapenemase detection was not reliable after 6 h.<br />Conclusions: Inhibition zone reading at 6 h is an accurate method for susceptibility testing of extended-spectrum cephalosporins for Enterobacteriaceae. For other antimicrobials, 6 h reading can be used for preliminary reports of clearly resistant or susceptible isolates, preferably with application of adjusted breakpoints including an area of uncertainty between susceptible and resistant values.<br /> (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Subjects :
- Bacterial Proteins metabolism
Cefotaxime pharmacology
Escherichia coli isolation & purification
Escherichia coli metabolism
Humans
Klebsiella pneumoniae isolation & purification
Klebsiella pneumoniae metabolism
Reagent Kits, Diagnostic
Reproducibility of Results
Time Factors
beta-Lactamases biosynthesis
beta-Lactamases metabolism
beta-Lactams pharmacology
Anti-Bacterial Agents pharmacology
Cephalosporins pharmacology
Escherichia coli drug effects
Klebsiella pneumoniae drug effects
Microbial Sensitivity Tests
Subjects
Details
- Language :
- English
- ISSN :
- 1460-2091
- Volume :
- 72
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- The Journal of antimicrobial chemotherapy
- Publication Type :
- Academic Journal
- Accession number :
- 27999046
- Full Text :
- https://doi.org/10.1093/jac/dkw515