Candida dubliniensis: phylogeny and putative virulence factors.
Candida dubliniensis is a recently identified species which is implicated in oral candidosis in HIV-infected and AIDS patients. The species shares many phenotypic characteristics with, and is phylogenetically closely related to, Candida albicans. In this study the phylogenetic relationship between these two species was investigated and a comparison of putative virulence factors was performed. Four isolates of C. dubliniensis from different clinical sources were chosen for comparison with two reference C. albicans strains. First, the distinct phylogenetic position of C. dubliniensis was further established by the comparison of the sequence of its small rRNA subunit with representative Candida species. The C. dubliniensis isolates formed true unconstricted hyphae under most induction conditions tested but failed to produce true hyphae when induced using N-acetylglucosamine. Oral C. dubliniensis isolates were more adherent to human buccal epithelial cells than the reference C. albicans isolates when grown in glucose and equally adherent when grown in galactose. The C. dubliniensis isolates were sensitive to fluconazole, itraconazole, ketoconazole and amphotericin B. Homologues of seven tested C. albicans secretory aspartyl proteinase (SAP) genes were detected in C. dubliniensis by Southern analysis. In vivo virulence assays using a systemic mouse model suggest that C. dubliniensis is marginally less virulent than C. albicans. These data further confirm the distinct phenotypic and genotypic nature of C. dubliniensis and suggest that this species may be particularly adapted to colonization of the oral cavity.
D Gilfillan
Gregor
G
Department of Molecular and Cell Biology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 ZZD, UK.
Derek J
Sullivan
S
The Moyne Institute of Preventive Medicine, Department of Microbiology, University of Dublin, Trinity College, Dublin 2, Republic of Ireland.|Department of Oral Medicine and Oral Pathology, School of Dental Science, University of Dublin, Trinity College, Dublin 2, Republic of Ireland.
Parkinson
Tanya
T
Department of Molecular and Cell Biology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 ZZD, UK.
Coleman
David C
DC
Department of Molecular and Cell Biology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 ZZD, UK.
Gow
Neil A R
NAR
Department of Molecular and Cell Biology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 ZZD, UK.
D000818:Animals; D015139:Blotting, Southern; D002175:Candida / Q000145:classification / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D002176:Candida albicans / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000382:microbiology; D005260:Female; D005800:Genes, Fungal / Q000235:genetics; D006801:Humans; D051379:Mice; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009061:Mouth Mucosa / Q000382:microbiology; D009693:Nucleic Acid Hybridization / Q000235:genetics; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012331:RNA, Fungal / Q000096:biosynthesis / Q000235:genetics; D012335:RNA, Ribosomal / Q000096:biosynthesis / Q000235:genetics; D017423:Sequence Analysis, RNA; D014621:Vagina / Q000382:microbiology; D014774:Virulence
D012331:RNA, Fungal; D012335:RNA, Ribosomal