Comparison of screening methods for detection of extended-spectrum β- lactamases and their prevalence among Escherichia coli and Klebsiella species in Hong Kong

P. L. Ho, D. N.C. Tsang, T. L. Que, M. Ho, K. Y. Yuen

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

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 languageEnglish
Pages (from-to)237-240
Number of pages4
JournalAPMIS
Volume108
Issue number3
DOIs
Publication statusPublished - 2000
Externally publishedYes

ASJC Scopus Subject Areas

  • Pathology and Forensic Medicine
  • Immunology and Allergy
  • Microbiology (medical)

Keywords

  • Escherichia coli
  • Extended-spectrum β-lactamases
  • Klebsiella species
  • Screening methods

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