Bloodstream Infections Due to Trichosporon spp.: Species Distribution, Trichosporon asahii Genotypes Determined on the Basis of Ribosomal DNA Intergenic Spacer 1 Sequencing, and Antifungal Susceptibility Testing

• Published in: Journal of Clinical Microbiology 2009-04, Vol.47 (4), p.1074-1081
• Main Authors: Chagas-Neto, Thomas C, Chaves, Guilherme M, Melo, Analy S.A, Colombo, Arnaldo L
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Antifungal Agents - pharmacology; Bacterial diseases; Bacterial sepsis; Biological and medical sciences; Child; Child, Preschool; DNA, Fungal - chemistry; DNA, Fungal - genetics; DNA, Ribosomal Spacer - chemistry; DNA, Ribosomal Spacer - genetics; Female; Fundamental and applied biological sciences. Psychology; Fungemia - epidemiology; Genotype; Human bacterial diseases; Humans; Infant; Infant, Newborn; Infectious diseases; Male; Medical sciences; Microbial Sensitivity Tests; Microbiology; Middle Aged; Miscellaneous; Molecular Sequence Data; Mycology; Mycoses - epidemiology; Phylogeny; Prevalence; Sequence Analysis, DNA; South America - epidemiology; Trichosporon; Trichosporon - classification; Trichosporon - drug effects; Trichosporon - genetics; Trichosporon - isolation & purification; Trichosporon asahii; Trichosporon asteroides; Trichosporon beigelii; Trichosporon dermatis
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/JCM.01614-08

The reevaluation of the genus Trichosporon has led to the replacement of the old taxon Trichosporon beigelii by six new species. Sequencing of the ribosomal DNA (rDNA) intergenic spacer 1 (IGS1) is currently mandatory for accurate Trichosporon identification, but it is not usually performed in routine laboratories. Here we describe Trichosporon species distribution and prevalence of Trichosporon asahii genotypes based on rDNA IGS1 sequencing as well as antifungal susceptibility profiles of 22 isolates recovered from blood cultures. The clinical isolates were identified as follows: 15 T. asahii isolates, five Trichosporon asteroides isolates, one Trichosporon coremiiforme isolate, and one Trichosporon dermatis isolate. We found a great diversity of different species causing trichosporonemia, including a high frequency of isolation of T. asteroides from blood cultures that is lower than that of T. asahii only. Regarding T. asahii genotyping, we found that the majority of our isolates belonged to genotype 1 (86.7%). We report the first T. asahii isolate belonging to genotype 4 in South America. Almost 50% of all T. asahii isolates exhibited amphotericin B MICs of greater-than-or-equal2 μg/ml. Caspofungin MICs obtained for all the Trichosporon sp. isolates tested were consistently high (MICs greater-than-or-equal 2 μg/ml). Most isolates (87%) had high MICs for 5-flucytosine, but all of them were susceptible to triazoles, markedly to voriconazole (all MICs [less-than or equal to] 0.06 μg/ml).