title: Real-world experience with echinocandin MICs against Candida species in a multicenter study of hospitals that routinely perform susceptibility testing of bloodstream isolates.
abstract: Reference broth microdilution methods of Candida echinocandin susceptibility testing are limited by interlaboratory variability in caspofungin MICs. Recently revised Clinical and Laboratory Standards Institute (CLSI) breakpoint MICs for echinocandin nonsusceptibility may not be valid for commercial tests employed in hospital laboratories. Indeed, there are limited echinocandin susceptibility testing data from hospital laboratories. We conducted a multicenter retrospective study of 9 U.S., Australian, and New Zealand hospitals that routinely tested Candida bloodstream isolates for echinocandin susceptibility from 2005 to 2013. Eight hospitals used Sensititre YeastOne assays. The Candida spp. were C. albicans (n=1,067), C. glabrata (n=911), C. parapsilosis (n=476), C. tropicalis (n=185), C. krusei (n=104), and others (n=154). Resistance and intermediate rates were ≤1.4% and ≤3%, respectively, for each echinocandin against C. albicans, C. parapsilosis, and C. tropicalis. Resistance rates among C. glabrata and C. krusei isolates were ≤7.5% and ≤5.6%, respectively. Caspofungin intermediate rates among C. glabrata and C. krusei isolates were 17.8% and 46.5%, respectively, compared to ≤4.3% and ≤4.4% for other echinocandins. Using CLSI breakpoints, 18% and 19% of C. glabrata isolates were anidulafungin susceptible/caspofungin nonsusceptible and micafungin susceptible/caspofungin nonsusceptible, respectively; similar discrepancies were observed for 38% and 39% of C. krusei isolates. If only YeastOne data were considered, interhospital modal MIC variability was low (within 2 doubling dilutions for each agent). In conclusion, YeastOne assays employed in hospitals may reduce the interlaboratory variability in caspofungin MICs against Candida species that are observed between reference laboratories using CLSI broth microdilution methods. The significance of classifying isolates as caspofungin intermediate and anidulafungin/micafungin susceptible will require clarification in future studies.
authors.affiliation: Department of Pharmacy and Antibiotic Management Program, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Eschenauer
authors.forename: M Hong
authors.initials: MH
authors.lastname: Nguyen
authors.forename: Shmuel
authors.initials: S
authors.lastname: Shoham
authors.forename: Jose A
authors.initials: JA
authors.lastname: Vazquez
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Morris
authors.forename: William A
authors.initials: WA
authors.lastname: Pasculle
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Kubin
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Klinker
authors.forename: Peggy L
authors.initials: PL
authors.lastname: Carver
authors.forename: Kimberly E
authors.initials: KE
authors.lastname: Hanson
authors.forename: Sharon
authors.initials: S
authors.lastname: Chen
authors.forename: Simon W
authors.initials: SW
authors.lastname: Lam
authors.forename: Brian A
authors.initials: BA
authors.lastname: Potoski
authors.forename: Lloyd G
authors.initials: LG
authors.lastname: Clarke
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Shields
authors.forename: Cornelius J
authors.initials: CJ
authors.lastname: Clancy
mesh_terms: D000077612:Anidulafungin; D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D000077336:Caspofungin; D054714:Echinocandins / Q000494:pharmacology*; D006801:Humans; D055666:Lipopeptides / Q000494:pharmacology; D000077551:Micafungin; D008826:Microbial Sensitivity Tests
chemical_list: D000935:Antifungal Agents; D054714:Echinocandins; D055666:Lipopeptides; D000077612:Anidulafungin; D000077336:Caspofungin; D000077551:Micafungin