title: Intra- and Interlaboratory Agreement in Assessing the In Vitro Activity of Micafungin against Common and Rare Candida Species with the EUCAST, CLSI, and Etest Methods.
abstract: The emergence of resistant strains among common and rare Candida species necessitates continuous monitoring of the in vitro susceptibilities of those isolates. We therefore assessed the in vitro activities of micafungin against 1,099 molecularly identified isolates belonging to 5 common and 20 rare Candida species by the EUCAST, CLSI, and Etest methods, assessing both the intralaboratory agreement and the interlaboratory agreement for two centers. The median micafungin EUCAST MICs were as follows, from the lowest to the highest: for Candida albicans, 0.004 mg/liter; for C. glabrata, 0.016 mg/liter; for C. tropicalis, 0.031 mg/liter; for C. krusei, 0.125 mg/liter; for C. parapsilosis, 2 mg/liter. Among rare Candida species, high MICs were found for C. guilliermondii, C. lipolytica, C. orthopsilosis, C. metapsilosis, and C. fermentati. No resistant isolates were found by the CLSI method, whereas resistance rates of 1 to 2% were found by the EUCAST method. Overall, the EUCAST method resulted in MICs 1 to 2 dilutions higher than those found by the CLSI and Etest methods. The intra- and interlaboratory agreement between methods was >92%, except for the interlaboratory agreement between the EUCAST and CLSI methods (81%), where 17 to 31% of the differences were >2 2-fold dilutions for C. albicans, C. glabrata, C. tropicalis, and other rare Candida species and <6% for C. parapsilosis and C. krusei For the other interlaboratory comparisons, the EUCAST method resulted in higher MICs than the Etest method for all species, but <7% of these differences were >2 2-fold dilutions. Overall, the CLSI method resulted in lower MICs than the Etest method, with 11% of all isolates demonstrating >2 2-fold-dilution differences (6 to 20% for C. albicans, C. tropicalis, and rare Candida species; <5% for C. glabrata, C. krusei, and C. parapsilosis) and smaller differences found after 24 h. Despite these differences, categorical agreement was excellent (>97%), with only 1 to 2% very major errors between the EUCAST method and the other two methods.
authors.affiliation: Clinical Microbiology Laboratory, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands jmeletiadis@med.uoa.gr.
authors.forename: J
authors.initials: J
authors.lastname: Meletiadis
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Geertsen
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands.
authors.forename: I
authors.initials: I
authors.lastname: Curfs-Breuker
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: J F
authors.identifier: 0000-0003-3253-6080
authors.initials: JF
authors.lastname: Meis
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Mouton
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D054714:Echinocandins / Q000494:pharmacology*; D007753:Laboratories / Q000592:standards; D055666:Lipopeptides / Q000494:pharmacology*; D000077551:Micafungin; D008826:Microbial Sensitivity Tests / Q000379:methods* / Q000592:standards
chemical_list: D000935:Antifungal Agents; D054714:Echinocandins; D055666:Lipopeptides; D000077551:Micafungin