Establishment of epidemiological cutoff values for clinically relevant Sporothrix species using CLSI-broth microdilution
Year: 2026
Type: article
Abstract: ABSTRACT Sporotrichosis is a globally distributed subcutaneous mycosis caused mainly by Sporothrix brasiliensis , S. schenckii , and S. globosa . Cat-transmitted sporotrichosis, primarily caused by S. brasiliensis in South America and to a lesser extent by S. schenckii in Southeast Asia, is emerging as a substantial public health concern due to its outbreak potential. Itraconazole is the first-line drug for the treatment of humans and cats, but reduced susceptibility has been reported based on previously proposed epidemiological cut-off values (ECVs). To support resistance surveillance, we aimed to establish the Clinical and Laboratory Standards Institute (CLSI)-endorsed ECVs for these clinically relevant Sporothrix species. A total of 3,504 minimum inhibitory concentration (MIC) values for six antifungal agents (amphotericin B, itraconazole, posaconazole, voriconazole, isavuconazole, and terbinafine) were obtained from 19 international laboratories. Four of seven antifungals met the CLSI M57 guidelines criteria to determine the ECV. Established ECVs for amphotericin B were found to be high, with 8 µg/mL for S. brasiliensis and S. globosa , and 4 µg/mL for S. schenckii . Itraconazole ECVs were 4 µg/mL for S. brasiliensis and S. schenckii . Posaconazole ECVs were 4 µg/mL for all three species (tentative for S. globosa ), while the terbinafine ECV for S. brasiliensis was 0.12 µg/mL. Overall, this study establishes validated ECVs for key antifungals against Sporothrix species and identifies a low prevalence of non-wild-type (NWT) isolates (<10% except for S. schenckii and posaconazole), supporting ongoing antifungal resistance monitoring.
DOI: 10.1128/aac.01907-25
Authors: Amanda R. dos Santos, Alexandro Bonifaz, Amanda Bombassaro, Ana Caroline de Sá Machado, Anderson M. Rodrigues, Andrew M. Borman, Arunaloke Chakrabarti, Anuradha Chowdary, Bruno Rediguieri, Elizabeth M. Johnson, Ferry Hagen, Flavio Queiroz-Telles, Gloria M. Gonzalez, Guillermo Garcia-Effron, Isabella Dib Ferreira Gremião, Jacques F. Meis, Juliana Possato Fernandes Takahashi, Luana Pereira Borba dos Santos, Marcia S. C. Melhem, Paola Cappellano, Raimunda Sâmia Nogueira Brilhante, Sandro Antonio Pereira, Sarah Santos Gonçalvez, Sarah Kidd, Sean X. Zhang, Shivaprakash Rudramurthy, Sonia Rozental, Susana Cordoba, Theun De Groot, Wei Liu, Nathan P. Wiederhold, Eelco F. J. Meijer, Shawn R. Lockhart, Philippe J. Dufresne
Institutions: Centers for Disease Control and Prevention, Universidade de São Paulo, Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, Hospital General de México, Canisius-Wilhelmina Ziekenhuis, Universidade Federal do Paraná, Fundação Oswaldo Cruz, Universidade Federal de São Paulo, University of Exeter, MRC Centre for Medical Mycology, University of Delhi, Universidade Federal do Espírito Santo, University Medical Center Utrecht, Universidad Autónoma de Nuevo León, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Litoral, Centro Científico Tecnológico - Santa Fe, University of Cologne, Instituto Adolfo Lutz, Universidade Federal do Rio de Janeiro, Universidade Federal de Mato Grosso do Sul, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Fundação Faculdade de Medicina, Fleury S.A. (Brazil), Universidade Federal do Ceará, South Australia Pathology, Johns Hopkins University, Johns Hopkins Medicine, Johns Hopkins Hospital, Post Graduate Institute of Medical Education and Research, Administración Nacional de Laboratorios e Institutos de Salud, Peking University First Hospital, The University of Texas at San Antonio Health Science Center, Institut National de Santé Publique du Québec
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
Award: G4623441924
OpenAlex ID: W7150901181