Lichtheimia hongkongensis sp. nov., a novel Lichtheimia spp. associated with rhinocerebral, gastrointestinal, and cutaneous mucormycosis

Three thermotolerant "Absidia-like" isolates with unique morphologic characteristics, recovered from nasopharyngeal swab of a liver transplant recipient, gastric biopsy of a renal transplant recipient, and skin biopsy of a man with burn, respectively, were characterized. Microscopic examination showed nonseptate hyphae with highly branched sporangiophores. Uniquely, most side branches were circinate, and abundant pleomorphic giant cells with fingerlike projections were observed, characteristics absent from other Absidia/. Lichtheimia spp. ITS1-5.8S-ITS2 rRNA gene cluster, partial EF1α gene, and partial β-actin gene sequencing showed that the 3 strains formed a distinct cluster, most closely related to, but distinct from, Lichtheimia corymbifera, Lichtheimia blakesleeana, and Lichtheimia hyalospora. Based on the morphologic and genotypic characteristics, we propose a new species, Lichtheimia hongkongensis sp. nov., to describe this fungus, which caused rhinocerebral, gastrointestinal, and cutaneous mucormycosis, respectively, in 3 patients. A significant proportion of L. corymbifera associated with mucormycosis reported may be L. hongkongensis.