Multicenter evaluation of the reproducibility of the proposed antifungal susceptibility testing method for fermentative XXXX of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST).

@entity9841 @entity2380 @entity7408 @entity4895 @entity7409 @entity5132 @entity19323 @entity375 @entity413 @entity2059
OBJECTIVE: To evaluate the intra- and inter-laboratory reproducibility of a new standard for susceptibility testing of fermentative @entity375 . This standard is based on the M27-A procedure of the National Committee for Clinical Laboratory Standards (NCCLS), but incorporates several modifications, including spectrophotometric growth-dependent endpoint reading. METHODS: Nine laboratories participated in the study. Common material lots were used to test six Candida species (one each of @entity5132 , @entity9841 , @entity7409 , @entity7408 , C. krusei, and @entity19323 ), and two quality control strains (C. krusei ATCC6258 and @entity7409 @entity7409 ). Triplicate testing on three separate days was performed in microtiter format with RPMI-2% @entity413 , pH 7.0. @entity4895 , @entity2380 and @entity2059 were tested. In total, 3888 MIC values were included in the analyses. Reproducibility was calculated by means of agreement (percentage of MICs within one two-fold dilution of the mode) and intraclass correlation coefficient (ICC, maximum value of 1). RESULTS: The average intra-laboratory agreements were 99% and 96% after 24 h and 48 h of incubation, respectively, with ICCs of 0.98 and 0.97 (P < 0.05). Two strains exhibiting a trailing effect showed intra-laboratory agreement of 92% and ICCs of < 0.91 at 48 h. The inter-laboratory agreement was 94% and 88% after 24 h and 48 h, respectively, with ICCs of 0.93 and 0.91 (P < 0.05). Lower values of agreement and ICCs were obtained for strains exhibiting trailing after 48 h of incubation. @entity2059 yielded the lowest values of reproducibility. CONCLUSION: The new procedure of EUCAST for antifungal susceptibility testing is a reproducible method within and between laboratories and offers several advantages over the NCCLS approved method.
