title: Clinical spectrum of exophiala infections and a novel Exophiala species, Exophiala hongkongensis.
abstract: We characterized 12 Exophiala strains isolated from patients over a 15-year period to the species level using phenotypic tests and internal transcribed spacer (ITS) and Rpb1 sequencing and described the clinical spectrum of the 12 patients. Eight patients had nail or skin infections, two had invasive infections, and two had colonization of the gastrointestinal tract. ITS and Rpb1 sequencing showed that 11 of the 12 strains were known Exophiala species (E. oligosperma [n = 3], E. jeanselmei [n = 2], E. lecanii-corni [n = 2], E. bergeri [n = 1], E. cancerae [n = 1], E. dermatitidis [n = 1], and E. xenobiotica [n = 1]), which included the first reported cases of onychomycosis caused by E. bergeri and E. oligosperma. The 12th strain (HKU32(T)), isolated from the nail clipping of the right big toe of a 68-year-old female patient with onychomycosis, possessed unique morphological characteristics distinct from other Exophiala species. It grew very slowly and had a velvety colony texture after 28 days, short conidiophores of the same olivaceous color as the supporting hyphae, numerous spores, and no chlamydospore-like cells. ITS, Rpb1, β-tubulin, and β-actin gene sequencing unambiguously showed that HKU32(T) was clustered with but formed branches distinct from other Exophiala species in phylogenetic trees. We propose the new species Exophiala hongkongensis to describe this novel fungus.
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong, China. pcywoo@hkucc.hku.hk
authors.forename: Patrick C Y
authors.initials: PC
authors.lastname: Woo
authors.forename: Antonio H Y
authors.initials: AH
authors.lastname: Ngan
authors.forename: Chris C C
authors.initials: CC
authors.lastname: Tsang
authors.forename: Ian W H
authors.initials: IW
authors.lastname: Ling
authors.forename: Jasper F W
authors.initials: JF
authors.lastname: Chan
authors.forename: Shui-Yee
authors.initials: SY
authors.lastname: Leung
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
authors.forename: Susanna K P
authors.initials: SK
authors.lastname: Lau
mesh_terms: D000199:Actins / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002675:Child, Preschool; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005093:Exophiala / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D008969:Molecular Sequence Data; D016533:Mycological Typing Techniques; D060446:Phaeohyphomycosis / Q000382:microbiology* / Q000473:pathology*; D010802:Phylogeny; D012319:RNA Polymerase II / Q000235:genetics; D017422:Sequence Analysis, DNA; D014404:Tubulin / Q000235:genetics; D055815:Young Adult
chemical_list: D000199:Actins; D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D014404:Tubulin; D012319:RNA Polymerase II