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 >2 g/ml. Caspofungin MICs obtained for all the Trichosporon sp. isolates tested were consistently high (MICs > 2 g/ml). Most isolates (87%) had high MICs for 5-flucytosine, but all of them were susceptible to triazoles, markedly to voriconazole (all MICs < 0.06 g/ml).The incidence of invasive mycoses caused by emergent fungal pathogens has risen considerably over the last two decades. This fact is related to several factors, including the increased occurrence of degenerative and malignant diseases in different populations, as well as the higher number of patients exposed to organ transplantation, immunosuppressive therapies, chemotherapy, broad-spectrum antibiotics, and invasive medical procedures. It is important to emphasize that emergent fungal infections are usually difficult to diagnose, refractory to conventional antifungal drugs, and associated with high mortality rates (8,10,26,32,34,47,51).Invasive infections caused by Trichosporon spp. are reported mostly for cancer patients that have central venous catheters (22,(50)(51)(52). Although trichosporonemia represents a small percentage of all fungal invasive infections, Trichosporon spp. have been reported as the second-or third-most-common agents of yeast fungemia (13,21,51).Phenotypic methods for Trichosporon species identification usually generate inconsistent results, and none of the commercial tests available include the whole new taxonomic categories in their databases (1, 36, 37). For instance, it has been mentioned in the literature that an isolate identified by molecular methods as Trichosporon dermatis was mistakenly identified as Trichosporon mucoides when Vitek Systems 1 and 2 (BioMérieux, France) were used (16). Furthermore, Ahmad et al.(1) reported that four isolates previously identified by Vitek 2 as Trichosporon asahii were identified as Trichosporon asteroides by molecular technique...