ABSTRACT
The physiological patterns, the sequence polymorphisms of the internal transcriber spacer (ITS), and intergenic spacer regions (IGS) of the rRNA genes and the antifungal susceptibility profile were evaluated for their ability to identify Trichosporon spp. and their specificity for the identification of 49 clinical isolates of Trichosporon spp. Morphological and biochemical methodologies were unable to differentiate among the Trichosporon species. ITS sequencing was also unable to differentiate several species. However, IGS1 sequencing unambiguously identified all Trichosporon isolates. Following the results of DNA-based identification, Trichosporon asahii was the species most frequently isolated from deep sites (15 of 25 strains; 60%). In the main, other Trichosporon species were recovered from cutaneous samples. The majority of T. asahii, T. faecale, and T. coremiiforme clinical isolates exhibited resistance in vitro to amphotericin B, with geometric mean (GM) MICs >4 mug/ml. The other species of Trichosporon did not show high MICs of amphotericin B, and GM MICs were <1 mug/ml. Azole agents were active in vitro against the majority of clinical strains. The most potent compound in vitro was voriconazole, with a GM MIC
Subject(s)
DNA, Intergenic , DNA, Ribosomal Spacer , Polymorphism, Genetic , Trichosporon/classification , Trichosporon/genetics , Trichosporon/physiology , Amphotericin B/pharmacology , Antifungal Agents/pharmacology , Argentina/epidemiology , DNA, Fungal/analysis , DNA, Fungal/genetics , DNA, Intergenic/analysis , DNA, Intergenic/genetics , DNA, Ribosomal/analysis , DNA, Ribosomal/genetics , DNA, Ribosomal Spacer/analysis , DNA, Ribosomal Spacer/genetics , Disease Susceptibility , Drug Resistance, Fungal/genetics , Humans , Microbial Sensitivity Tests , Phylogeny , RNA, Fungal/analysis , RNA, Fungal/genetics , RNA, Ribosomal/analysis , RNA, Ribosomal/genetics , Retrospective Studies , Sequence Analysis, DNA , Spain/epidemiology , Trichosporon/drug effects , Trichosporon/growth & development , Trichosporon/isolation & purificationABSTRACT
Seven cases of disseminated infection due to Dipodascus capitatus are reported. Infections occurred in a hematological unit of a tertiary hospital during a period of 5 years. Five cases were refractory to antifungal therapy. Antifungal susceptibility testing of seven isolates was performed, and strains were typed by PCR fingerprinting with the core sequence of phage M13 and by random amplification of polymorphic DNA with two primers, Ap12h and W-80A. A very short range of MICs of each antifungal agent was observed. The MICs of amphotericin B ranged between 0.50 and 2 microg/ml. Strains were susceptible in vitro to flucytosine and susceptible (dose-dependent) to fluconazole and itraconazole. Voriconazole exhibited an activity in vitro comparable to that of itraconazole. Typing techniques allowed seven additional isolates of D. capitatus neither geographically nor temporally related to be classified into two different genomic patterns. The genomic type of the seven strains from the hematological unit was identical regardless of typing technique utilized. It would indicate that the seven cases of disseminated infection could be related epidemiologically.
