title: Multicenter evaluation of the reproducibility of the proposed antifungal susceptibility testing method for fermentative yeasts of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST).
abstract: OBJECTIVE
  To evaluate the intra- and inter-laboratory reproducibility of a new standard for susceptibility testing of fermentative yeasts. 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 C. albicans, C. tropicalis, C. parapsilosis, C. glabrata, C. krusei, and C. lusitaniae), and two quality control strains (C. krusei ATCC6258 and C. parapsilosis ATCC22019). Triplicate testing on three separate days was performed in microtiter format with RPMI-2% glucose, pH 7.0. Flucytosine, fluconazole and itraconazole 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. Itraconazole yielded the lowest values of reproducibility.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Instituto de Salud Carlos III, Majadahonda, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Cuenca-Estrella
authors.forename: C B
authors.initials: CB
authors.lastname: Moore
authors.forename: F
authors.initials: F
authors.lastname: Barchiesi
authors.forename: J
authors.initials: J
authors.lastname: Bille
authors.forename: E
authors.initials: E
authors.lastname: Chryssanthou
authors.forename: D W
authors.initials: DW
authors.lastname: Denning
authors.forename: J P
authors.initials: JP
authors.lastname: Donnelly
authors.forename: F
authors.initials: F
authors.lastname: Dromer
authors.forename: B
authors.initials: B
authors.lastname: Dupont
authors.forename: J H
authors.initials: JH
authors.lastname: Rex
authors.forename: M D
authors.initials: MD
authors.lastname: Richardson
authors.forename: B
authors.initials: B
authors.lastname: Sancak
authors.forename: P E
authors.initials: PE
authors.lastname: Verweij
authors.forename: J L
authors.initials: JL
authors.lastname: Rodríguez-Tudela
mesh_terms: D026683:Advisory Committees; D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D005060:Europe; D015725:Fluconazole / Q000494:pharmacology; D005437:Flucytosine / Q000494:pharmacology*; D017964:Itraconazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000592:standards; D015337:Multicenter Studies as Topic; D015203:Reproducibility of Results
chemical_list: D000935:Antifungal Agents; D017964:Itraconazole; D015725:Fluconazole; D005437:Flucytosine