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, July 2003, p. 3142-3146, Vol. 41, No. 7
0095-1137/03/$08.00+0     DOI: 10.1128/JCM.41.7.3142-3146.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Evaluation of the NCCLS Extended-Spectrum ß-Lactamase Confirmation Methods for Escherichia coli with Isolates Collected during Project ICARE

Fred C. Tenover,1* Patti M. Raney,1 Portia P. Williams,2 J. Kamile Rasheed,1 James W. Biddle,1 Antonio Oliver,3 Scott K. Fridkin,1 Laura Jevitt,1 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 Servicio de Microbiología, Hospital Son Dureta, 07014 Palma de Mallorca, Spain3

Received 20 February 2003/ Returned for modification 8 April 2003/ Accepted 21 April 2003

To determine whether confirmatory tests for extended-spectrum ß-lactamase (ESBL) production in Escherichia coli are necessary, we selected 131 E. coli isolates that met the National Committee for Clinical Laboratory Standards (NCCLS) screening criteria for potential ESBL production from the Project ICARE (Intensive Care Antimicrobial Resistance Epidemiology) strain collection. For all 131 isolates, the broth microdilution (BMD) MIC of at least one extended-spectrum cephalosporin was >=2 µg/ml. For 21 of 131 (16%) isolates, the ESBL confirmatory test was positive; i.e., the BMD MICs of ceftazidime or cefotaxime decreased by >=3 doubling dilutions in the presence of clavulanic acid (CA) or the disk diffusion zone diameters increased by >=5 mm around ceftazidime or cefotaxime disks in the presence of CA. All 21 isolates were shown by PCR to contain at least one of the genes blaTEM, blaSHV, and blaOXA, and in isoelectric focusing (IEF) tests, all isolates demonstrated at least one ß-lactamase band consistent with a TEM, SHV, or OXA enzyme. Of the 21 isolates, 3 showed a CA effect for cefotaxime by BMD but not by disk diffusion testing. A total of 59 (45%) of the 131 isolates demonstrated decreased susceptibility to cefpodoxime alone (MIC = 2 to 4 µg/ml), and none had a positive ESBL confirmatory test result. These were classified as false positives according to ESBL screen test results. For the remaining 51 (39%) isolates, the cefpodoxime MICs ranged from 16 to >128 µg/ml and the MICs for the other extended-spectrum cephalosporins were highly variable. All 51 isolates gave negative ESBL confirmatory test results. Most showed IEF profiles consistent with production of both a TEM and an AmpC ß-lactamase, and representative isolates of several phenotypic groups showed changes in porin profiles; these 51 isolates were considered true negatives. In all, only 16% of 131 E. coli isolates identified as potential ESBL producers by the current NCCLS screening criteria were confirmed as ESBL producers. Thus, changing the interpretation of extended-spectrum cephalosporins and aztreonam results from the susceptible to the resistant category without confirming the presence of an ESBL phenotype would lead to a large percentage of false resistance results and is not recommended. However, by increasing the cefpodoxime MIC screening breakpoint to >= BORDER="0">8 µg/ml, 45% of the false-positive results could be eliminated. NCCLS has incorporated this change in the cefpodoxime screening breakpoint in its recent documents.

* Corresponding author. Mailing address: Division of Healthcare Quality Promotion (G-08), Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA 30333. Phone: (404) 639-3375. Fax: (404) 639-1381. E-mail: fnt1{at}cdc.gov.

Journal of Clinical Microbiology, July 2003, p. 3142-3146, Vol. 41, No. 7
0095-1137/03/$08.00+0     DOI: 10.1128/JCM.41.7.3142-3146.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Fisher, M. A., Stamper, P. D., Hujer, K. M., Love, Z., Croft, A., Cohen, S., Bonomo, R. A., Carroll, K. C., Petti, C. A. (2009). Performance of the Phoenix bacterial identification system compared with disc diffusion methods for identifying extended-spectrum {beta}-lactamase, AmpC and KPC producers. J Med Microbiol 58: 774-778 [Abstract] [Full Text]  
  • Lee, J., Pai, H., Kim, Y. K., Kim, N. H., Eun, B. W., Kang, H. J., Park, K. H., Choi, E. H., Shin, H. Y., Kim, E. C., Lee, H. J., Ahn, H. S. (2007). Control of extended-spectrum {beta}-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a children's hospital by changing antimicrobial agent usage policy. J Antimicrob Chemother 60: 629-637 [Abstract] [Full Text]  
  • Spanu, T., Sanguinetti, M., Tumbarello, M., D'Inzeo, T., Fiori, B., Posteraro, B., Santangelo, R., Cauda, R., Fadda, G. (2006). Evaluation of the New VITEK 2 Extended-Spectrum Beta-Lactamase (ESBL) Test for Rapid Detection of ESBL Production in Enterobacteriaceae Isolates.. J. Clin. Microbiol. 44: 3257-3262 [Abstract] [Full Text]  
  • Chmelnitsky, I., Carmeli, Y., Leavitt, A., Schwaber, M. J., Navon-Venezia, S. (2005). CTX-M-2 and a New CTX-M-39 Enzyme Are the Major Extended-Spectrum Beta-Lactamases in Multiple Escherichia coli Clones Isolated in Tel Aviv, Israel. Antimicrob. Agents Chemother. 49: 4745-4750 [Abstract] [Full Text]  
  • Paterson, D. L., Bonomo, R. A. (2005). Extended-Spectrum {beta}-Lactamases: a Clinical Update. Clin. Microbiol. Rev. 18: 657-686 [Abstract] [Full Text]  
  • Thiolas, A., Bollet, C., La Scola, B., Raoult, D., Pages, J.-M. (2005). Successive Emergence of Enterobacter aerogenes Strains Resistant to Imipenem and Colistin in a Patient. Antimicrob. Agents Chemother. 49: 1354-1358 [Abstract] [Full Text]  
  • Lavigne, J.-P., Bouziges, N., Chanal, C., Mahamat, A., Michaux-Charachon, S., Sotto, A. (2004). Molecular Epidemiology of Enterobacteriaceae Isolates Producing Extended-Spectrum {beta}-Lactamases in a French Hospital. J. Clin. Microbiol. 42: 3805-3808 [Abstract] [Full Text]  
  • Schwaber, M. J., Raney, P. M., Rasheed, J. K., Biddle, J. W., Williams, P., McGowan, J. E. Jr., Tenover, F. C. (2004). Utility of NCCLS Guidelines for Identifying Extended-Spectrum {beta}-Lactamases in Non-Escherichia coli and Non-Klebsiella spp. of Enterobacteriaceae. J. Clin. Microbiol. 42: 294-298 [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»