Multilaboratory study of epidemiological cutoff values for detection of resistance in eight Candida species to fluconazole

Identificador:  PC:733

Handle: https://hdl.handle.net/20.500.11797/PC733

Autors:  Espinel-Ingroff, A.; Pfaller, M.A.; Bustamante, B.; Canton, E.; Fothergill, A.; Fuller, J.; Gonzalez, G.M.; Lass-Flörl, C.; Lockhart, S.R.; Martin-Mazuelos, E.; Meis, J.F.; Melhem, M.S.C.; Ostrosky-Zeichner, L.; Pelaez, T.; Szeszs, M.W.; St-Germain, G.; Bonfietti, L.X.; Guarro, J.; Turnidge, J.

Resum:
Although epidemiological cutoff values (ECVs) have been established for Candida spp. and the triazoles, they are based on MIC data from a single laboratory. We have established ECVs for eight Candida species and fluconazole, posaconazole, and voricona- zole based on wild-type (WT) MIC distributions for isolates of C. albicans ( n 11,241 isolates), C. glabrata (7,538), C. parapsi- losis (6,023), C. tropicalis (3,748), C. krusei (1,073), C. lusitaniae (574), C. guilliermondii (373), and C. dubliniensis (162). The 24-h CLSI broth microdilution MICs were collated from multiple laboratories (in Canada, Brazil, Europe, Mexico, Peru, and the United States). The ECVs for distributions originating from > 6 laboratories, which included > 95% of the modeled WT popula- tion, for fluconazole, posaconazole, and voriconazole were, respectively, 0.5, 0.06 and 0.03 g/ml for C. albicans , 0.5, 0.25, and 0.03 g/ml for C. dubliniensis , 8, 1, and 0.25 g/ml for C. glabrata , 8, 0.5, and 0.12 g/ml for C. guilliermondii , 32, 0.5, and 0.25 g/ml for C. krusei , 1, 0.06, and 0.06 g/ml for C. lusitaniae , 1, 0.25, and 0.03 g/ml for C. parapsilosis , and 1, 0.12, and 0.06 g/ml for C. tropicalis . The low number of MICs ( < 100) for other less prevalent species ( C. famata , C. kefyr , C. orthopsilo- sis , C. rugosa ) precluded ECV definition, but their MIC distributions are documented. Evaluation of our ECVs for some species/ agent combinations using published individual MICs for 136 isolates (harboring mutations in or upregulation of ERG11 , MDR1 , CDR1 ,or CDR2 ) and 64 WT isolates indicated that our ECVs may be useful in distinguishing WT from non-WT isolates.