Subcutaneous Phaeohyphomycotic Nodule Due to Phialemoniopsis hongkongensis sp. nov.

Abstract

<i>Phialemoniopsis</i> species are ubiquitous dematiaceous moulds associated with a wide variety of superficial and systemic infections in human. In this study, we isolated a mould from the forearm nodule biopsy specimen from a patient with underlying liver cirrhosis, ankylosing spondylosis, and tuberculosis. He was treated with itraconazole, but unfortunately, he succumbed as a result of disseminated tuberculosis with multiorgan failure. The histology results of the skin biopsy showed necrotizing granulomas in which numerous fungal elements were found. On Sabouraud dextrose agar, the fungal isolate grew as white-to-cream and smooth-to-velvety colonies. Microscopically, oval-to-cylindrical conidia were observed from abundant adelophialides, which possessed barely visible parallel collarettes but no basal septa. The azole drugs voriconazole, itraconazole, and posaconazole, as well as amphotericin B, showed high activities against this fungus. Internal transcribed spacer (ITS), 28S nuclear ribosomal DNA (nrDNA), and β-actin and β-tubulin gene sequencing showed that this fungus is most closely related to but distinct from Phialemoniopsis curvata. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) and hierarchical cluster analysis showed that the MALDI-TOF MS spectrum of this fungus is most closely related to that of <i>Phialemoniopsis pluriloculosa</i>. We propose a new species, <i>Phialemoniopsis hongkongensis</i> sp. nov., to describe this fungus.