An international evaluation of MIC distributions and ECV definition for Fusarium species identified by molecular methods for the CLSI broth microdilution method.

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An international evaluation of MIC distributions and ECV definition for Fusarium species identified by molecular methods for the CLSI broth microdilution method.

Antimicrob Agents Chemother. 2015 Dec 7;

Authors: Espinel-Ingroff A, Colombo AL, Cordoba S, Dufresne PJ, Fuller J, Ghannoum M, Gonzalez GM, Guarro J, Kidd SE, Meis JF, Melhem TM, Pelaez T, Pfaller MA, Szeszs MW, Takahaschi JP, Tortorano AM, Wiederhold NP, Turnidge J

Abstract
CLSI epidemiological cutoff values (ECVs) of antifungal agents are available for various Candida spp., Aspergillus spp. and the Mucorales. However, those categorical endpoints have not been established for Fusarium spp., mostly due to the difficulties associated with collecting sufficient CLSI MICs for clinical isolates identified according to the currently recommended molecular DNA-PCR based identification methodologies. CLSI MIC distributions were established for 53 Fusarium dimerum species complex (SC), 10 F. fujikuroi, 82 F. proliferatum, 20 F. incarnatum-equiseti SC, 226 F. oxysporum SC, 608 F. solani SC, and 151 F. verticillioides isolates originating in 17 laboratories (Argentina, Australia, Brazil, Canada, Europe, Mexico and the United States). According to the CLSI guidelines for ECV definition, ECVs encompassing ≥97.5% of pooled statistically modeled MIC populations were as follows: amphotericin B ECVs of 4 μg/ml (F. verticillioides) and 8 μg/ml (F. oxysporum SC and F. solani SC); posaconazole ECVs of 2 μg/ml (F. verticillioides), 8 μg/ml (F. oxysporum SC), and 32 μg/ml (F. solani SC); voriconazole ECVs of 4 μg/ml (F. verticillioides), 16 μg/ml (F. oxysporum SC) and 32 μg/ml (F. solani SC); and itraconazole ECVs of 32 μg/ml (F. oxysporum SC and F. solani SC). Insufficient data precluded ECV definition for the other species. Although these ECVs could aid in detecting non-WT isolates with reduced susceptibility to the agents evaluated, the relationship between molecular mechanisms of resistance (gene mutations) and MICs needs to be investigated for Fusarium spp.

PMID: 26643334 [PubMed - as supplied by publisher]