Citations

ABSTRACT The ability to identify yeast isolates by the new enzymatic RapID Yeast Plus System was compared to the ability to identify yeast isolates by the API 20C system. A total of 447 yeast isolates representing Blastoschizomyces capitatus , 17 Candida spp., 5 Cryptococcus spp., Geotrichum spp., 2 Hanseniaspora spp., Hansenula anomala , Hansenula wingei , 3 Rhodotorula spp., Saccharomyces cerevisiae , Sporobolomyces salmonicolor , Trichosporon beigelii , and 2 Prototheca spp. were evaluated. Also, five quality control strains ( Candida spp. and Cryptococcus laurentii ) with well-documented reactivities by the RapID Yeast Plus System were used. Each isolate was evaluated by both methods with a 48-h culture grown at 30°C on Sabouraud dextrose agar (Emmons modification) by following the recommendations of the manufacturers. The RapID Yeast Plus System enzymatic reactions were read after 4 h of incubation, and the API 20C carbohydrate assimilation identification profiles were obtained after 72 h of incubation. There was good (95.7%) agreement between the identifications obtained by the two methods with the eight common Candida spp. and with Cryptococcus neoformans . The agreement was lower when the emerging Candida spp. and other yeast-like pathogens were tested (79.1 and 75.2%, respectively). These preliminary data suggest the potential utility of the RapID Yeast Plus System for use in the clinical laboratory for the rapid identification of common yeast pathogens as well as certain new and emerging species.

Although the Sensititre Yeast-One (SYO) and Etest methods are widely utilized, interpretive criteria are not available for triazole susceptibility testing of Candida or Aspergillus species. We collected fluconazole, itraconazole, posaconazole, and voriconazole SYO and Etest MICs from 39 laboratories representing all continents for (method/agent-dependent) 11,171 Candida albicans , 215 C. dubliniensis , 4,418 C. glabrata species complex, 157 C. guilliermondii ( Meyerozyma guilliermondii ), 676 C. krusei ( Pichia kudriavzevii ), 298 C. lusitaniae ( Clavispora lusitaniae ), 911 C. parapsilosis sensu stricto , 3,691 C. parapsilosis species complex, 36 C. metapsilosis , 110 C. orthopsilosis , 1,854 C. tropicalis , 244 Saccharomyces cerevisiae , 1,409 Aspergillus fumigatus , 389 A. flavus , 130 A. nidulans , 233 A. niger , and 302 A. terreus complex isolates.

ABSTRACTNeither breakpoints (BPs) nor epidemiological cutoff values (ECVs) have been established forCandidaspp. with anidulafungin, caspofungin, and micafungin when using the Sensititre YeastOne (SYO) broth dilution colorimetric method. In addition, reference caspofungin MICs have so far proven to be unreliable.Candidaspecies wild-type (WT) MIC distributions (for microorganisms in a species/drug combination with no detectable phenotypic resistance) were established for 6,007Candida albicans, 186C. dubliniensis, 3,188C. glabratacomplex, 119C. guilliermondii, 493C. krusei, 205C. lusitaniae, 3,136C. parapsilosiscomplex, and 1,016C. tropicalisisolates. SYO MIC data gathered from 38 laboratories in Australia, Canada, Europe, Mexico, New Zealand, South Africa, and the United States were pooled to statistically define SYO ECVs. ECVs for anidulafungin, caspofungin, and micafungin encompassing ≥97.5% of the statistically modeled population were, respectively, 0.12, 0.25, and 0.06 μg/ml forC. albicans, 0.12, 0.25, and 0.03 μg/ml forC. glabratacomplex, 4, 2, and 4 μg/ml forC. parapsilosiscomplex, 0.5, 0.25, and 0.06 μg/ml forC. tropicalis, 0.25, 1, and 0.25 μg/ml forC. krusei, 0.25, 1, and 0.12 μg/ml forC. lusitaniae, 4, 2, and 2 μg/ml forC. guilliermondii, and 0.25, 0.25, and 0.12 μg/ml forC. dubliniensis. Species-specific SYO ECVs for anidulafungin, caspofungin, and micafungin correctly classified 72 (88.9%), 74 (91.4%), 76 (93.8%), respectively, of 81Candidaisolates with identifiedfksmutations. SYO ECVs may aid in detecting non-WT isolates with reduced susceptibility to anidulafungin, micafungin, and especially caspofungin, since testing the susceptibilities ofCandidaspp. to caspofungin by reference methodologies is not recommended.