Species diversity of Aspergillus section Versicolores in clinical samples and antifungal susceptibility.

Aspergillus section Versicolores includes species of clinical relevance and many others that have been poorly studied but are occasionally found in clinical samples. The aim of this study was to investigate, using a multilocus phylogenetic approach, the spectrum of species of the section Versicolores and to determine their in vitro antifungal susceptibility. The study was based on a set of 77 clinical isolates from different USA medical centres, which had been previously identified as belonging to this section. The genetic markers used were internal transcribed spacer (ITS), ß-tubulin (BenA), calmodulin (CaM), and RNA polymerase II second largest subunit (RPB2), and the drugs tested, following the CLSI guidelines, were amphotericin B (AMB), itraconazole, posaconazole, voriconazole, anidulafungin, caspofungin, micafungin, terbinafine (TBF), and flucytosine (5FC). The most frequent species were Aspergillus sydowii (26 %), Aspergillus creber (22 %), and Aspergillus amoenus (18.2 %), followed by Aspergillus protuberus (13 %), Aspergillus jensenii (10.4 %), and Aspergillus tabacinus (5.2 %); while Aspergillus cvjetkovicii, Aspergillus fructus, Aspergillus puulaauensis, and Aspergillus versicolor were represented by only one isolate each (1.3 %). This is the first time that A. jensenii and A. puulaauensis have been reported from clinical samples. Considering the high number of isolates identified as belonging to this fungal group in this study, its clinical relevance should not be overlooked. Aspergillus versicolor, traditionally considered one of the most common species in this section in a clinical setting, was only rarely recovered in our study. The in vitro antifungal results showed that echinocandins and TBF were the most potent drugs, the azoles showed variable results, AMB was poorly active, and 5FC was the less active.

Sporothrix brasiliensis, S. globosa, and S. mexicana, three new Sporothrix species of clinical interest.

Sporothrix schenckii is the species responsible for sporotrichosis, a fungal infection caused by the traumatic implantation of this dimorphic fungus. Recent molecular studies have demonstrated that this species constitutes a complex of numerous phylogenetic species. Since the delineation of such species could be of extreme importance from a clinical point of view, we have studied a total of 127 isolates, most of which were received as S. schenckii, including the available type strains of species currently considered synonyms, and also some close morphological species. We have phenotypically characterized all these isolates using different culture media, growth rates at different temperatures, and numerous nutritional tests and compared their calmodulin gene sequences. The molecular analysis revealed that Sporothrix albicans, S. inflata, and S. schenckii var. luriei are species that are clearly different from S. schenckii. The combination of these phenetic and genetic approaches allowed us to propose the new species Sporothrix brasiliensis, S. globosa, and S. mexicana. The key phenotypic features for recognizing these species are the morphology of the sessile pigmented conidia, growth at 30, 35, and 37 degrees C, and the assimilation of sucrose, raffinose, and ribitol.

Nosocomial outbreak of Exophiala jeanselmei fungemia associated with contamination of hospital water.

From December 1996 through September 1997, we diagnosed 19 cases of fungemia due to Exophiala jeanselmei. We conducted a matched case-control study in which we cultured specimens of blood products, intravenous solutions, and water from a hospital water system. Isolates from environmental cultures were compared to those recovered from patients by random amplification of polymorphic DNA (RAPD). Multivariate analysis showed that neutropenia, longer duration of hospitalization, and use of corticosteroids were risk factors for infection. Environmental cultures yielded E. jeanselmei from 3 of 85 sources: deionized water from the hospital pharmacy, 1 water tank, and water from a sink in a non-patient care area. Use of deionized pharmacy water to prepare antiseptic solutions was discontinued, and no additional cases of infection occurred. RAPD typing showed that isolates from case patients and isolates from the pharmacy water were highly related, whereas the patterns of isolates recovered from the 2 other sources of water were distinct.