This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tenover, F. C.
Right arrow Articles by McGowan, J. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tenover, F. C.
Right arrow Articles by McGowan, J. E., Jr.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, February 2009, p. 294-299, Vol. 47, No. 2
0095-1137/09/$08.00+0     doi:10.1128/JCM.01797-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Identification of Plasmid-Mediated AmpC β-Lactamases in Escherichia coli, Klebsiella spp., and Proteus Species Can Potentially Improve Reporting of Cephalosporin Susceptibility Testing Results {triangledown}

Fred C. Tenover,1 Shannon L. Emery,2 Carol A. Spiegel,3 Patricia A. Bradford,4 Samantha Eells,2,{dagger} Andrea Endimiani,5 Robert A. Bonomo,5 and John E. McGowan Jr.2*

Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30333,1 Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322,2 Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin 53792,3 Wyeth Research, Pearl River, New York 10965,4 Louis Stokes Department of Veterans Affairs Medical Center, Cleveland Ohio 441065

Received 17 September 2008/ Returned for modification 29 October 2008/ Accepted 18 November 2008

The goal of this study was to determine if the interpretations of extended-spectrum and advanced-spectrum cephalosporins (ESCs and ASCs, respectively) for isolates of Enterobacteriaceae would be impacted by the results of aminophenylboronic acid (APBA) testing. Fifty-three isolates of Escherichia coli, 21 Klebsiella species, and 6 Proteus species that were resistant to at least one ESC were tested by disk diffusion with ceftazidime and cefotetan disks with and without APBA. Ceftazidime disks with and without clavulanic acid (CLAV) were also tested to confirm extended-spectrum β-lactamase (ESBL) carriage. Twenty-nine (36.3%) isolates were only APBA test positive, 27 were only CLAV test positive, 2 were positive with both substrates, and 22 were negative with both substrates. Thirteen (41.9%) of the 31 APBA-test-positive isolates (all E. coli) tested susceptible to cefotaxime, ceftriaxone, or ceftazidime. Since clinical data suggest that AmpC-producing isolates should be reported as resistant to all ESCs, APBA testing can be helpful in identifying such organisms. Screening for AmpC-producing organisms using nonsusceptibility to cefoxitin and amoxicillin-clavulanate was less specific than APBA testing; it identified ESBL as well as AmpC-producing organisms. Only 18 of 31 APBA-positive isolates were positive by PCR for an AmpC β-lactamase gene. Thus, testing with APBA could improve the accuracy of reporting ESCs, especially for E. coli. However, results of APBA and CLAV testing did not correlate well for isolates containing both AmpC β-lactamases and ESBLs. Thus, additional data are needed before formal recommendations can be made on changing the reporting of ASC test results.

* Corresponding author. Mailing address: Department of Epidemiology, Rollins School of Public Health, Emory University, 1518 Clifton Rd., Atlanta, GA 30322. Phone and fax: (404) 727-9365. E-mail: jmcgowa{at}sph.emory.edu

{triangledown} Published ahead of print on 26 November 2008.

{dagger} Present address: Los Angeles BioMedical Research Institute, Torrance, CA 90502.

Journal of Clinical Microbiology, February 2009, p. 294-299, Vol. 47, No. 2
0095-1137/09/$08.00+0     doi:10.1128/JCM.01797-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Doi, Y., Paterson, D. L., Adams-Haduch, J. M., Sidjabat, H. E., O'Keefe, A., Endimiani, A., Bonomo, R. A. (2009). Reduced Susceptibility to Cefepime among Escherichia coli Clinical Isolates Producing Novel Variants of CMY-2 {beta}-Lactamase. Antimicrob. Agents Chemother. 53: 3159-3161 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»