Hepatic phaeohyphomycosis due to a novel dematiaceous fungus, sp. nov., and importance of antifungal susceptibility testing.

species are wood-inhabiting fungi and emerging opportunistic pathogens causing phaeohyphomycosis. In this study, we isolated a dematiaceous fungus, HKU44, from the subhepatic abscess pus and drain fluids of a liver transplant recipient with post-transplant biliary and hepatico-jejunostomy bypass strictures. Histology of the abscess wall biopsy showed abundant fungal hyphae. The patient survived after a second liver transplant and antifungal therapy. On SDA, HKU44 grew initially as white powdery colonies which turned beige upon maturation. Hyphae were septate and hyaline. Phialides were monophialidic and laterally located, generally closely associated to a cluster of conidia which were usually reniform. Phylogenetic analyses showed that HKU44 is most closely related to, but distinct from, and . These suggested that HKU44 is a novel species, for which the name sp. nov. is proposed. Antifungal susceptibility testing showed that species possessed high MICs/MECs for fluconazole, 5-flucytosine and the echinocandins; whereas they exhibited a high strain-to-strain variability to the susceptibilities to the other triazoles. As for amphotericin B, ∼65% of the strains had low MICs (≤1 µg/mL). DNA sequencing should be performed to accurately identify fungi with -like morphologies, so is antifungal susceptibility testing for patients with infections.