The change of morphology and antifungal susceptibility inTrichosporon asahii by in-vivo passage and in-vitro induction

doi:10.11786/sypfbxzz.1674-1293.20150103

Abstract：ObjectiveTo investigate the change of morphology and antifungal drug susceptibility inT.asahii by murine passage and lfuconazole in vitro induction. MethodsFourT.asahii strains were ifve passaged through murine hosts; the shape of colony and cell type were observed, and the minimal inhibitory concentration(MIC) to lfuconazole were measured for the prepassage and postpassage isolates. Furthermore, twoT.asahii strains, including a clinical isolate CBS2479 and an environmental isolate CBS 8904, were respectively and serially subcultured in solid medium containing growing concentrations of lfuconazole. Changes in morphology and MIC value of the induced isolates were observed.ResultsIn all the passaged isolates in vivo and induced isolates in vitro, morphologies and drug susceptibilities to lfuconazole were signiifcantly different from the original isolates, where the lfuconazole MIC value of clinical passaged isolates was increased 8 times relates to prepassage MIC, and cell type of environmental isolates, which the morphological characteristics observed with microscopes, changed from dominated by spores to containing spores and hyphae. After in-vitro induction, high level of lfuconazole resistance (MIC>256 μg/ml) developed in both the clinical isolates and the environmental isolates, and the latter changed their MIC value more signiifcantly, meanwhile from dominated by hyphae to spores of cell types. ConclusionMorphologies and antifungal susceptibilities to lfuconazole inT.asahii were changed by in-vivo passage and in-vitro induction. The morphologies of passaged environmental isolates in vivo have trends to the clinical isolate, which is contrary with in-vitro induction. Both in-vivo passage and in-vitro induction, the increased range of lfuconazole MIC value in the clinical isolates is signiifcantly greater than environmental isolates. The lfuconazole in-vitro induction increased higher and faster level of MIC value then in-vivo passage.