Open AccessMulticenter Comparative Evaluation of Six Commercial Systems and the National Committee for Clinical Laboratory Standards M27-A Broth Microdilution Method for Fluconazole Susceptibility Testing of Candida Species
Author(s) -
Giulia Morace,
Gerardino Amato,
Francesco Bistoni,
Giovanni Fadda,
Piero Marone,
Maria Teresa Montagna,
Salvatore Massimo Oliveri,
Luciano Polonelli,
Roberto Rigoli,
Isabella Mancuso,
Sofia La Face,
Luca Masucci,
Lucio Romano,
Christian Napoli,
D. Tatò,
Massimo Buscema,
C. M C Belli,
M. M. Piccirillo,
Stefania Conti,
Silvia Covan,
Franco Fanti,
Caterina Cavanna,
Del Francesco,
Lucia Pitzurra
Publication year - 2002
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.40.8.2953-2958.2002
Subject(s) - etest , fluconazole , broth microdilution , candida albicans , reproducibility , clinical microbiology , microbiology and biotechnology , corpus albicans , candida parapsilosis , candida krusei , antifungal , biology , medicine , chemistry , chromatography , minimum inhibitory concentration , antimicrobial
Fluconazole susceptibility among 800 clinical Candida isolates (60% C. albicans) and two control strains (C. krusei ATCC 6258 and C. parapsilosis ATCC 22019) was tested with the NCCLS M27-A method (gold standard) and six commercial products (Candifast, disk, Etest, Fungitest, Integral System Yeasts, and Sensititre YeastOne). Results were classified as susceptible, susceptible-dose dependent, or resistant using M27-A breakpoints or, for Fungitest, Integral System Yeasts, and Candifast, as susceptible, intermediate, or resistant, according to the manufacturers' instructions. Concordance with NCCLS M27-A results was analyzed with the chi(2) test. Intra- and interlaboratory reproducibility was also evaluated. NCCLS M27-A (90.1%), Etest (93.1%), Sensititre YeastOne (93.1%), disk (96.7%), Fungitest (92.6%), Integral System Yeasts (40.6%), and Candifast (6.0%) classified the indicated percentages of C. albicans isolates as susceptible. Among non-C. albicans strains, the percentages of susceptible isolates were as follows: NCCLS M27-A, 74.0%; Etest, 83.8%; Sensititre YeastOne, 64.1%; disk, 60.6%; Fungitest, 76.6%; Integral System Yeasts, 28.3%; and Candifast, 27.4%. All methods except Candifast and Integral System Yeasts showed good agreement with NCCLS M27-A results for both C albicans and non-C. albicans isolates. Intralaboratory reproducibility was excellent for NCCLS M27-A, Etest, Sensititre YeastOne, disk, and Fungitest (88 to 91%). Similar results emerged from the interlaboratory reproducibility evaluation. Our findings indicate that some commercial methods can be useful for fluconazole susceptibility testing of clinical Candida isolates. Those characterized by a lack of medium standardization and/or objective interpretative criteria should be avoided. Particular caution is necessary when testing is being done for clinical and epidemiological purposes.