Rapid disc diffusion antibiotic susceptibility testing for Pseudomonas aeruginosa, Acinetobacter baumannii and Enterococcus spp.
- Hombach M Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Schweiz.
- Jetter M Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Schweiz.
- Blöchliger N Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Schweiz.
- Kolesnik-Goldmann N Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Schweiz.
- Keller PM Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Schweiz.
- Böttger EC Institut für Medizinische Mikrobiologie, Universität Zürich, 8006 Zürich, Schweiz.
- 2017-11-30
Published in:
- The Journal of antimicrobial chemotherapy. - 2018
Acinetobacter baumannii
Anti-Bacterial Agents
Automation, Laboratory
Disk Diffusion Antimicrobial Tests
Enterococcus
Hospitals, University
Humans
Pseudomonas aeruginosa
Switzerland
Time Factors
English
Background
We investigated the feasibility of rapid disc diffusion antibiotic susceptibility testing (rAST) with reading of inhibition zones after 6 and/or 8 h of incubation for Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa and Acinetobacter baumannii. In addition, we evaluated discrimination of resistant populations from the WT populations at early timepoints and the requirement for clinical breakpoint adaptations for proper interpretation of rAST data.
Methods
In total, 815 clinical strains [E. faecalis (n = 135), E. faecium (n = 227), P. aeruginosa (n = 295) and A. baumannii (n = 158)] were included in this study. Disc diffusion plates were streaked, incubated and imaged using the WASPLabTM automation system. WT populations and non-WT populations were defined using epidemiological cut-offs.
Results and conclusions
rAST at 6 and 8 h was possible for A. baumannii and enterococci with readability of inhibition zones >90%. Overall categorical agreement of rAST at 6 h with AST at 18 h was 97.2%, 97.4% and 95.3% for E. faecalis, E. faecium and A. baumannii, respectively. With few exceptions, major categorization error rates were <1% for A. baumannii, and vancomycin-resistant E. faecium were clearly separated from the WT at 6 h. For P. aeruginosa the average readability of inhibition zones was 68.9% at 8 h and we found an overall categorical agreement of 94.8%. Adaptations of clinical breakpoints and/or introduction of technical buffer zones, preferably based on aggregated population data from various epidemiological settings, are required for proper interpretation of rAST.
We investigated the feasibility of rapid disc diffusion antibiotic susceptibility testing (rAST) with reading of inhibition zones after 6 and/or 8 h of incubation for Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa and Acinetobacter baumannii. In addition, we evaluated discrimination of resistant populations from the WT populations at early timepoints and the requirement for clinical breakpoint adaptations for proper interpretation of rAST data.
Methods
In total, 815 clinical strains [E. faecalis (n = 135), E. faecium (n = 227), P. aeruginosa (n = 295) and A. baumannii (n = 158)] were included in this study. Disc diffusion plates were streaked, incubated and imaged using the WASPLabTM automation system. WT populations and non-WT populations were defined using epidemiological cut-offs.
Results and conclusions
rAST at 6 and 8 h was possible for A. baumannii and enterococci with readability of inhibition zones >90%. Overall categorical agreement of rAST at 6 h with AST at 18 h was 97.2%, 97.4% and 95.3% for E. faecalis, E. faecium and A. baumannii, respectively. With few exceptions, major categorization error rates were <1% for A. baumannii, and vancomycin-resistant E. faecium were clearly separated from the WT at 6 h. For P. aeruginosa the average readability of inhibition zones was 68.9% at 8 h and we found an overall categorical agreement of 94.8%. Adaptations of clinical breakpoints and/or introduction of technical buffer zones, preferably based on aggregated population data from various epidemiological settings, are required for proper interpretation of rAST.
- Language
-
- English
- Open access status
- hybrid
- Identifiers
-
- DOI 10.1093/jac/dkx404
- PMID 29186434
- Persistent URL
- https://sonar.ch/global/documents/67552
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