title: A significant number of reported Absidia corymbifera (Lichtheimia corymbifera) infections are caused by Lichtheimia ramosa (syn. Lichtheimia hongkongensis): an emerging cause of mucormycosis.
abstract: Recently, we and others reported the discovery of Lichtheimia ramosa (syn. Lichtheimia hongkongensis). We also hypothesized that a proportion of 'Absidia corymbifera (Lichtheimia corymbifera)' reported in the literature could be L. ramosa. In this study, we characterized 13 strains that had been reported as 'A. corymbifera (L. corymbifera)' in the literature over an 11-year period. Microscopic examination of agar block smear preparations of all 13 strains showed abundant circinate side branches and pleomorphic giant cells with finger-like projections of L. ramosa. ITS1-5.8S-ITS2 rRNA gene cluster (internal transcribed spacer (ITS)) and partial elongation factor-1alpha (EF1α) gene sequencing showed that all 13 strains were clustered with L. ramosa; partial β-actin gene sequencing showed that most of the 13 strains were clustered with L. ramosa; and partial 28S rRNA gene sequencing showed that all 13 strains were clustered with L. ramosa, but one strain of L. corymbifera (HKU25) was also clustered with other strains of L. ramosa. A significant number of reported A. corymbifera (L. corymbifera) infections are L. ramosa infections which are of global distribution. In clinical microbiology laboratories, L. ramosa should be suspected if an Absidia-like mold that possesses abundant circinate side branches on the sporangiophores and pleomorphic giant cells with finger-like projections is observed. ITS and partial EF1α gene sequencing are more reliable than partial β-actin and 28S rRNA gene sequencing for identification of the Lichtheimia species.
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China ; State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong , Hong Kong, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong, China ; Carol Yu Centre for Infection, The University of Hong Kong , Hong Kong, China.
authors.forename: Patrick Cy
authors.initials: PC
authors.lastname: Woo
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China.
authors.forename: Shui-Yee
authors.initials: SY
authors.lastname: Leung
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China.
authors.forename: Antonio Hy
authors.initials: AH
authors.lastname: Ngan
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China ; State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong , Hong Kong, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong, China ; Carol Yu Centre for Infection, The University of Hong Kong , Hong Kong, China.
authors.forename: Susanna Kp
authors.initials: SK
authors.lastname: Lau
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China ; State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong , Hong Kong, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong, China ; Carol Yu Centre for Infection, The University of Hong Kong , Hong Kong, China.
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
keywords: ITS sequencing; fungus; identification; infection