JAC Advance Access originally published online on April 14, 2003
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Journal of Antimicrobial Chemotherapy (2003) 51, 1191-1202
© 2003 The British Society for Antimicrobial Chemotherapy
Comparative evaluation of the VITEK 2 Advanced Expert System (AES) in five UK hospitals
1 Department of Microbiology, University Hospital, Birmingham; 2 Department of Microbiology, Ninewells Hospital, Dundee; 3 Department of Infection, Guy’s & St Thomas’ Hospital, London; 4 Department of Microbiology, Basildon Hospital, Basildon, Essex; 5 Department of Microbiology, Royal Hallamshire Hospital, Glossop Road, Sheffield, UK
Received 3 January 2003; returned 18 February 2003; revised 18 February 2003; accepted 26 February 2003
Objectives: We carried out an evaluation of VITEK 2 in five UK laboratories, comparing results with ‘gold standard’ agar-dilution MIC data, assessing its ability to recognize resistant phenotypes and comparing results with those generated by routine antimicrobial susceptibility testing methods.
Methods: Laboratories tested a collection of 82 strains selected on the basis of their challenging and characterized resistance mechanisms.
Results: In comparison with the reference MIC method, VITEK 2 gave an essential agreement of 304/315 (enterococci), 1619/1674 (staphylococci) and 2937/3074 (Gram-negative bacilli): overall 96.0% agreement. Corresponding category (SIR) agreements with VITEK 2 were 247/252, 1496/1561 and 2478/2626 (overall 95.1%). Using five routine methodologies, category agreements ranged from 58/63 to 45/45; 222/232 to 174/174, and 333/372 to 250/259 for the three organism groups with an overall agreement of 95.0%. In contrast to VITEK 2 Advanced Expert System (AES), routine microbiology laboratories did not attempt to detect resistance mechanisms for every antibiotic studied. VITEK 2 AES detected all 19 resistance mechanisms in enterococci: where applicable, routine methods detected 14, 10 and 10. Of 30 resistance mechanisms in staphylococci, VITEK 2 AES detected 25 compared with 23, 20, 17 and 18 detected by routine methods. Finally, of 44 resistance mechanisms in Gram-negative bacilli, VITEK 2 AES detected 30 compared with 30, 23, 15 and 10 detected by routine methods.
Conclusions: VITEK 2 performed susceptibility tests accurately and the AES detected and interpreted resistance mechanisms appropriately. Heavy inocula in a liquid medium possibly favour better expression of certain resistance determinants. Although certain routine microbiology methods performed adequately, VITEK 2 AES offers a rapid, standardized method suited to laboratories lacking experience of resistance mechanisms and/or those not testing an appropriate number, or range, of antibiotics to detect resistance phenotypes.
Keywords: VITEK 2; Expert; automated AST
* Corresponding author. Tel: +44-114-271-3121; Fax: +44-114-278-9376; E-mail: tgwinstanley{at}hotmail.com
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. Farber, K.-A. Moder, F. Layer, I. Tammer, W. Konig, and B. Konig Extended-Spectrum Beta-Lactamase Detection with Different Panels for Automated Susceptibility Testing and with a Chromogenic Medium J. Clin. Microbiol., November 1, 2008; 46(11): 3721 - 3727. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S.-Y. Lee, J. K. Yu, S. Y. Lee, S. H. Shin, H.-I. Park, E.-J. Oh, and Y.-J. Park Evaluation of the VITEK 2 Advanced Expert System for Reporting Piperacillin Susceptibility in Klebsiella spp. Antimicrob. Agents Chemother., June 1, 2008; 52(6): 2291 - 2292. [Full Text] [PDF]
|
|
|
|
 |
|
 N. Woodford and A. Sundsfjord Molecular detection of antibiotic resistance: when and where? J. Antimicrob. Chemother., August 1, 2005; 56(2): 259 - 261. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. de Cueto, E. Ceballos, L. Martinez-Martinez, E. J. Perea, and A. Pascual Use of Positive Blood Cultures for Direct Identification and Susceptibility Testing with the Vitek 2 System J. Clin. Microbiol., August 1, 2004; 42(8): 3734 - 3738. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Rahman, I. Kuhn, M. Rahman, B. Olsson-Liljequist, and R. Mollby Evaluation of a Scanner-Assisted Colorimetric MIC Method for Susceptibility Testing of Gram-Negative Fermentative Bacteria Appl. Envir. Microbiol., April 1, 2004; 70(4): 2398 - 2403. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-L. Donay, D. Mathieu, P. Fernandes, C. Pregermain, P. Bruel, A. Wargnier, I. Casin, F. X. Weill, P. H. Lagrange, and J. L. Herrmann Evaluation of the Automated Phoenix System for Potential Routine Use in the Clinical Microbiology Laboratory J. Clin. Microbiol., April 1, 2004; 42(4): 1542 - 1546. [Abstract] [Full Text] [PDF]
|
|