Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology

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pISSN 2288-0585 eISSN 2288-6850

Evaluation of VITEK-2 Antifungal Susceptibility Test (AST-YS01) for Candida Species Isolates in Korea

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2009 September, Volume 12, Issue 3, pages 122-128.

https://doi.org/10.5145/ACM.2009.12.3.122

Evaluation of VITEK-2 Antifungal Susceptibility Test (AST-YS01) for Candida Species Isolates in Korea

Da-Woon Kim, Jong Hee Shin, Seung Jung Kee, Soo-Hyun Kim, Myung Geun Shin, Soon Pal Suh, Dong Wook Ryang

Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea

Abstract

Background: VITEK-2 yeast susceptibility test (AST- YS01; bioMerieux, Hazelwood, MO, USA) has recently been introduced as a fully automated commercial antifungal susceptibility test system that determines MIC (minimum inhibitory concentrations) endpoints spectrophotometrically, thereby eliminating subjective errors. We compared the VITEK-2 system with the CLSI (the Clinical and Laboratory Standards Institute) M27 method for susceptibility testing of Candida isolates from Korea.

Methods: A total of 175 Candida bloodstream isolates were collected from two hospitals during a 18-month period. We compared the MIC results for amphotericin B, fluconazole and voriconazole obtained with the VITEK-2 system to those obtained by the CLSI M27 broth microdilution method after 24-hr and 48-hr incubation.

Results: VITEK-2 system MIC endpoints for 175 isolates were determined after 11.75 to 35.50 hr of incubation (mean, 16.3±4.8 hr). The essential agreement (within 2 dilutions) between amphotericin B, fluconazole and voriconazole MICs obtained by the VITEK-2 system and CLSI method was 98.3%, 90.9% and 96.0%, respectively, at 24-hr incubation and 100%, 92.6% and 94.9%, at 48-hr incubation. The categorical discrepancy for fluconazole was 6.3% (major error, 2.9% and minor error, 3.4%) at 24-hr and 6.3% (major error, 2.3% and minor error, 4.0%) at 48-hr. The categorical discrepancy for voriconazole was 1.7% (major error, 1.1% and minor error, 0.6%) at both 24-hr and 48-hr. There were no very major errors for fluconazole and voriconazole.

Conclusion: The VITEK-2 antifungal susceptibility test system appears to be rapid and highly correlative with the CLSI method, sugesting that this system can be effective for antifungal susceptibility testing for Candida species in the clinical laboratory. (Korean J Clin Microbiol 2009;12:122-128)

Keywords

Candida, VITEK-2, Antifungal susceptibility, CLSI