Minimal inhibitory concentration distributions and epidemiological cutoff values of five antifungal agents against Sporothrix brasiliensis |
Almeida-Paes, Rodrigo; Brito-Santos, Fábio; Figueiredo-Carvalho, Maria Helena Galdino; Machado, Ana Caroline Sá; Oliveira, Manoel Marques Evangelista; Pereira, Sandro Antonio; Gutierrez-Galhardo, Maria Clara & Zancopé-Oliveira, Rosely Maria
BACKGROUND Sporothrix brasiliensis is the most virulent sporotrichosis agent. This species usually responds to antifungal
drugs, but therapeutic failure can occur in some patients. Antifungal susceptibility tests have been performed on this species,
but no clinical breakpoints (CBPs) are available. In this situation, minimal inhibitory concentration (MIC) distributions and
epidemiological cutoff values (ECVs) support the detection of identification of resistant strains.
OBJECTIVES To study the MIC distributions of five antifungal drugs against S. brasiliensis and to propose tentative ECVs.
METHODS MICs of amphotericin B (AMB), itraconazole (ITR), ketoconazole (KET), posaconazole (POS), and terbinafine (TRB)
against 335 S. brasiliensis strains were determined by the Clinical and Laboratory Standards Institute broth microdilution method.
FINDINGS The proposed ECV, in μg/mL, for AMB, ITR, KET, POS, and TRB were 4.0, 2.0, 1.0, 2.0, and 0.25, respectively.
Percentages of wild-type strains in our population for the above antifungal drugs were 98.48, 95.22, 95.33, 100, and 97.67%,
MAIN CONCLUSIONS These ECVs will be useful to detect strains with resistance, to define CBPs, and to elaborate specific
therapeutic guidelines for S. brasiliensis. Rational use of antifungals is strongly recommended to avoid the emergence of resistant
strains and ensure the therapeutic effectiveness of sporotrichosis.
antifungal drug; minimum inhibitory concentration; Sporothrix brasiliensis