Background: Schizophyllum commune is a common environmental basidiomycete implicated in invasive and allergic fungal disease mainly in Asian countries. Its definitive identification is problematic as many isolates remain sterile in culture due to the lack of observable reproductive structures. Because phenotypic methods are inconclusive sequencing is required. Here we report the susceptibilty profile of posaconazole and caspofungin for 31 molecularly identified S. commune isolates. Methods: Thirty-one clinical and environmental isolates were obtained from the V.P. Chest Institute (n=27, clinical), India and the CBS-KNAW Fungal Biodiversity Centre (n=4, environmental), Netherlands. Identification of all the S. commune isolates was confirmed by sequencing of the ITS rDNA and the D1/D2 LSU regions. Antifungal susceptibility testing of all isolates was performed by slightly modified CLSI microbroth dilution method. The inoculum consisted of 2.5 x 104 - 5.0 x 104 hyphal fragments/spores per ml. Microtitre plates were incubated at 35oC for 96 h. and MIC end points were read visually. Results: The isolates had low MICs of posaconazole (GM, 0.11 μg/ml; MIC50 0.125 μg/ml ; MIC90 =1 μg/ml, range 8 μg/ml). Conclusion: MICs of posaconazole compare favorable with published data of other azoles and thus it is a potential alternative for itraconazole and voriconazole in the treatment of allergic bronchopulmonary and invasive mycosis due toS. commune. Echinocandins have comparable high MECs for this group of basidiomycetes as they have for Cryptococcus. Supported in part by a research grant from the Investigator Initiated Studies Program of Merck Sharp & Dohme Corp.. The opinions expressed in this abstract are those of the authors and do not necessarily represent those of Merck Sharp & Dohme Corp.
Full conference title:
53rd Interscience Conference on Antimicrobial Agents and Chemotherapy
- ICAAC, 53rd (2013)