Abstract
Three tests, the disk diffusion test, the double-disc synergy test and the inhibitor-potentiated disc diffusion test, were compared for their abilities to detect production of extended-spectrum β-lactamases (ESBL) in 702 Escherichia coli and 472 Klebsiella spp. strains from four hospitals. Eleven percent E. coli and 13% Klebsiella spp. were found to produce ESBL. As an indicator of ESBL activity, the sensitivities of the five extended- spectrum β-lactams were as follows: cefotaxime (100%), cefpodoxime (99.3%), ceftriaxone (98.6%), aztreonam (93%) and ceftazidime (57.7%) when interpreted using the National Committee for Clinical Laboratory Standards criteria. Their positive predictive values ranged from 67.8-83.8%. Both the inhibitor- potentiated disc diffusion test and the double-disc synergy test (at three inter-disc widths of 20, 25 and 30 mm) were capable of identifying all the ESBL-producers. However, at a single inter-disc width of 30 mm, the double- disc synergy test has limited sensitivity (83.8%). As a second test for confirming ESBL activity in strains with reduced susceptibility to β- lactams, the inhibitor-potentiated disc diffusion test is therefore a simple and reliable option.
Original language | English |
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Pages (from-to) | 237-240 |
Number of pages | 4 |
Journal | APMIS |
Volume | 108 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2000 |
Externally published | Yes |
ASJC Scopus Subject Areas
- Pathology and Forensic Medicine
- Immunology and Allergy
- Microbiology (medical)
Keywords
- Escherichia coli
- Extended-spectrum β-lactamases
- Klebsiella species
- Screening methods