This Article Full Text Full Text (PDF) Other Versions of this Article: JCM.01988-06v1 45/4/1167    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wiegand, I. Articles by Seifert, H. Search for Related Content PubMed PubMed Citation Articles by Wiegand, I. Articles by Seifert, H.

Detection of Extended-Spectrum Beta-Lactamases among Enterobacteriaceae by Use of Semiautomated Microbiology Systems and Manual Detection Procedures

Department of Medical Microbiology, Immunology and Parasitology, Pharmaceutical Microbiology Unit, University of Bonn, Bonn, Germany,¹ Section Infectiology, Institute of Hygiene, University of Heidelberg, Heidelberg, Germany,² Medical Microbiology and Infectious Diseases, School of Medicine, University of Wales, Swansea, Swansea SA2 8PP, United Kingdom,³ Institute of Medical Microbiology, Virology and Hygiene, Centre of Clinical Pathology, University-Hospital Hamburg-Eppendorf, Hamburg, Germany,⁴ Institute for Medical Microbiology, Immunology, and Hygiene, University of Cologne, Cologne, Germany⁵

Received 25 September 2006/ Returned for modification 12 January 2007/ Accepted 25 January 2007

Three commercially available microbiology identification and susceptibility testing systems were compared with regard to their ability to detect extended-spectrum ß-lactamase (ESBL) production in Enterobacteriaceae, i.e., the Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, MD), the VITEK 2 System (bioMérieux, Marcy l'Etoile, France), and the MicroScan WalkAway-96 System (Dade Behring, Inc., West Sacramento, CA), using routine testing panels. One hundred fifty putative ESBL producers were distributed blindly to three participating laboratories. Conventional phenotypic confirmatory tests such as the disk approximation method, the CLSI double-disk synergy test, and the Etest ESBL were also evaluated. Biochemical and molecular characterization of ß-lactamases performed at an independent laboratory was used as the reference method. One hundred forty-seven isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Citrobacter freundii, Serratia marcescens, Proteus mirabilis, Proteus vulgaris, and Morganella morganii were investigated. Of these isolates, 85 were identified as ESBL producers by the reference method. The remaining isolates were identified as non-ESBL producers; they were either hyperproducers of their chromosomal AmpC, Koxy, or SHV enzymes or lacked any detectable ß-lactamase activity. The system with the highest sensitivity for the detection of ESBLs was the Phoenix (99%), followed by the VITEK 2 (86%) and the MicroScan (84%); however, specificity was more variable, ranging from 52% (Phoenix) to 78% (VITEK 2). The performance of the semiautomated systems differed widely with the species investigated. The sensitivities of the conventional test methods ranged from 93 to 94%. The double-disk synergy test showed the highest specificity and positive predictive value among all test methods, i.e., 97% and 98%, respectively.

Published ahead of print on 7 February 2007.

This article has been cited by other articles:

• Thomson, K. S., Cornish, N. E., Hong, S. G., Hemrick, K., Herdt, C., Moland, E. S. (2007). Comparison of Phoenix and VITEK 2 Extended-Spectrum-{beta}-Lactamase Detection Tests for Analysis of Escherichia coli and Klebsiella Isolates with Well-Characterized {beta}-Lactamases. J. Clin. Microbiol. 45: 2380-2384 [Abstract] [Full Text]