Rodrigo Almeida-Paes1,+, Fábio Brito-Santos1, Maria Helena Galdino Figueiredo-Carvalho1, Ana Caroline Sá Machado2, Manoel Marques Evangelista Oliveira1, Sandro Antonio Pereira2, Maria Clara Gutierrez-Galhardo3, Rosely Maria Zancopé-Oliveira1
1Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Infectologia Evandro Chagas, Laboratório de Micologia, Rio de Janeiro, RJ, Brasil
2Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Infectologia Evandro Chagas, Laboratório de Pesquisa Clínica em Dermatozoonoses em Animais Domésticos, Rio de Janeiro, RJ, Brasil
3Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Infectologia Evandro Chagas, Laboratório de Pesquisa Clínica em Dermatologia Infecciosa, Rio de Janeiro, RJ, Brasil
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%, respectively.
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.
Financial support: FAPERJ (grant nº E-26/102.255/2013),
CNPq (grants nº 305487/2015-9, 304976/2013-0),
PAPES/Fiocruz (Grants 407771/2013-3, 407693/2012-2).
Received 7 December 2016
Accepted 16 January 2017