title: Epidemiological cutoff values for fluconazole, itraconazole, posaconazole, and voriconazole for six Candida species as determined by the colorimetric Sensititre YeastOne method.
abstract: In the absence of clinical breakpoints (CBP), epidemiological cutoff values (ECVs) are useful to separate wild-type (WT) isolates (without mechanisms of resistance) from non-WT isolates (those that can harbor some resistance mechanisms), which is the goal of susceptibility tests. Sensititre YeastOne (SYO) is a widely used method to determine susceptibility of Candida spp. to antifungal agents. The CLSI CBP have been established, but not for the SYO method. The ECVs for four azoles, obtained using MIC distributions determined by the SYO method, were calculated via five methods (three statistical methods and based on the MIC50 and modal MIC). Respectively, the median ECVs (in mg/liter) of the five methods for fluconazole, itraconazole, posaconazole, and voriconazole (in parentheses: the percentage of isolates inhibited by MICs equal to or less than the ECVs; the number of isolates tested) were as follows: 2 (94.4%; 944), 0.5 (96.7%; 942), 0.25 (97.6%; 673), and 0.06 (96.7%; 849) for Candida albicans; 4 (86.1%; 642), 0.5 (99.4%; 642), 0.12 (93.9%; 392), and 0.06 (86.9%; 559) for C. parapsilosis; 8 (94.9%; 175), 1 (93.7%; 175), 2 (93.6%; 125), and 0.25 (90.4%; 167) for C. tropicalis; 128 (98.6%; 212), 4 (95.8%; 212), 4 (96.0%; 173), and 2 (98.5; 205) for C. glabrata; 256 (100%; 53), 1 (98.1%; 53), 1 (100%; 33), and 1 (97.9%; 48) for C. krusei; 4 (89.2%; 93), 0.5 (100%; 93), 0.25 (100%; 33), and 0.06 (87.7%; 73) for C. orthopsilosis. All methods included ≥94% of isolates and yielded similar ECVs (within 1 dilution). These ECVs would be suitable for monitoring emergence of isolates with reduced susceptibility by using the SYO method.
authors.affiliation: Unidad de Microbiología Experimental, Centro de Investigación, Hospital La Fe, Valencia, Spain. canton_emi@gva.es
authors.forename: Emilia
authors.initials: E
authors.lastname: Cantón
authors.forename: Javier
authors.initials: J
authors.lastname: Pemán
authors.forename: Carmen
authors.initials: C
authors.lastname: Iñiguez
authors.forename: David
authors.initials: D
authors.lastname: Hervás
authors.forename: Jose L
authors.initials: JL
authors.lastname: Lopez-Hontangas
authors.forename: Cidalia
authors.initials: C
authors.lastname: Pina-Vaz
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Camarena
authors.forename: Isolina
authors.initials: I
authors.lastname: Campos-Herrero
authors.forename: Inmaculada
authors.initials: I
authors.lastname: García-García
authors.forename: Ana M
authors.initials: AM
authors.lastname: García-Tapia
authors.forename: Remedios
authors.initials: R
authors.lastname: Guna
authors.forename: Paloma
authors.initials: P
authors.lastname: Merino
authors.forename: Luisa
authors.initials: L
authors.lastname: Pérez del Molino
authors.forename: Carmen
authors.initials: C
authors.lastname: Rubio
authors.forename: Anabel
authors.initials: A
authors.lastname: Suárez
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001393:Azoles / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects* / Q000302:isolation & purification; D002177:Candidiasis / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D000935:Antifungal Agents; D001393:Azoles