Antifungal Susceptibility of the Aspergillus viridinutans Complex: Comparison of Two In Vitro Methods.

Cryptic species of Aspergillus fumigatus, including the Aspergillus viridinutans species complex, are increasingly reported to be causes of invasive aspergillosis. Their identification is clinically relevant, as these species frequently have intrinsic resistance to common antifungals. We evaluated the susceptibilities of 90 environmental and clinical isolates from the A. viridinutans species complex, identified by DNA sequencing of the calmodulin gene, to seven antifungals (voriconazole, posaconazole, itraconazole, amphotericin B, anidulafungin, micafungin, and caspofungin) using the reference European Committee on Antimicrobial Susceptibility Testing (EUCAST) method. The majority of species demonstrated elevated MICs of voriconazole (geometric mean [GM] MIC, 4.46 mg/liter) and itraconazole (GM MIC, 9.85 mg/liter) and had variable susceptibility to amphotericin B (GM MIC, 2.5 mg/liter). Overall, the MICs of posaconazole and the minimum effective concentrations of echinocandins were low. The results obtained by the EUCAST method were compared with the results obtained with Sensititre YeastOne (YO) panels. Overall, there was 67% agreement (95% confidence interval [CI], 62 to 72%) between the results obtained by the EUCAST method and those obtained with YO panels when the results were read at 48 h and 82% agreement (95% CI, 78 to 86%) when the results were read at 72 h. There was a significant difference in agreement between antifungals; agreement was high for amphotericin B, voriconazole, and posaconazole (70 to 86% at 48 h and 88 to 93% at 72 h) but was very low for itraconazole (37% at 48 h and 57% at 72 h). The agreement was also variable between species, with the maximum agreement being observed for A. felis isolates (85 and 93% at 48 and 72 h, respectively). Elevated MICs of voriconazole and itraconazole were cross-correlated, but there was no correlation between the other azoles tested.

Severe Chromoblastomycosis-Like Cutaneous Infection Caused by Chrysosporium keratinophilum.

Chrysosporium species are saprophytic filamentous fungi commonly found in the soil, dung, and animal fur. Subcutaneous infection caused by this organism is rare in humans. We report a case of subcutaneous fungal infection caused by Chrysosporium keratinophilum in a 38-year-old woman. The patient presented with severe chromoblastomycosis-like lesions on the left side of the jaw and neck for 6 years. She also got tinea corporis on her trunk since she was 10 years old. Chrysosporium keratinophilum was isolated from the tissue on the neck and scales on the trunk, respectively. The patient showed satisfactory response to itraconazole therapy, although she discontinued the follow-up.

Development of rapid and specific molecular discrimination methods for pathogenic emericella species.

Aspergillosis is an important mycosis caused primarily by Aspergillus fumigatus and its relatives. The genus Emericella is a teleomorph related to the Aspergillus section Nidulantes. The typical anamorphic stage species in this genus is Aspergillus nidulans, which is sometimes a significant agent in chronic granulomatous disease (CGD) patients. The mortality rate of osteomyelitis in CGD patients due to A. nidulans ( E. nidulans ) is very high compared to that due to A. fumigatus. Moreover, two Emericella species ( E. nidulans and E. quadrilineata ) from clinical specimens exhibit different sensitivities against several antifungal drugs. In aspergillosis, correct species identification is important for antifungal therapy. We attempted to develop rapid and specific molecular discrimination by polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) methods in the principal pathogenic Emericella species, and succeeded in establishing species-specific primers corresponding to the hydrophobin gene. These primers discriminate E. nidulans and E. quadrilineata rapidly and specifically. These methods and primers make it possible to diagnose etiological agents in aspergillosis quickly and easily.

Molecular phylogenetics of multiple genes on Aspergillus section Fumigati isolated from clinical specimens in Japan.

A phylogenetic study based on sequence analysis of the beta-tubulin, hydrophobin and calmodulin genes was performed in 19 strains of Aspergillus fumigatus and related species isolated from clinical specimens in Japan. Correlations between detailed morphology and phylogeny were examined. Species in the section Fumigati were divided into five clades: clade I, typical strains of A. fumigatus; clade II, species including A. lentulus and A. fumisynnematus; clade III, species including A. fumigatiaffinis and A. novofumigatus, clade IV, atypical strains of A. fumigatus including A. viridinutans; and clade V, species including A. brevipes, A. duricaulis and A. unilateralis. Most of the examined strains from clinical specimens in Japan clustered together in clade I and exhibit globose conidia with lobate-reticulate ornamentation. Other strains from clinical specimens were divided into two clades (clades II and IV). The strains in clades II and the six strains in clade IV exhibit conidia with microtuberculate ornamentation, while A. viridinutans-complex in clades IV and the strains in clade V have conidia with lobate-reticulate ornamentation. The six strains are clearly distinguished from A. viridinutans-complex and are considered to be related to Neosartorya udagawae. The maximal growth temperatures of clades I, II, IV and V were above 50 degrees C, 45 degrees C, 42 degrees C and 42 degrees C, respectively. These data are useful for classification of species within the Aspergillus section Fumigati.