title: Redefining the human oral mycobiome with improved practices in amplicon-based taxonomy: discovery of Malassezia as a prominent commensal.
abstract: Fungi are a large, complex group, increasingly recognized as emerging threats. Their roles as modifiers of health mandate accurate portrayals of fungal communities in humans. As an entry point into the airways and gastrointestinal tract, fungi in the mouth are relevant to several biocompartments. We have revised current practices in sequence-based taxonomy assignments and employed the improvements to address the question of the fungal genera present in the healthy human mouth. The human oral mycobiome was surveyed using massively parallel, high throughput sequencing of internal transcribed spacer 1 (ITS1) amplicons from saliva following robust extraction methods. Taxonomy was assigned by comparison to a curated reference dataset, followed by filtering with an empirically determined BLAST E-value match statistic (10(-42)). Nomenclature corrections further refined results by conjoining redundant names for a single fungal genus. Following these curation steps, about two-thirds of the initially identified genera were eliminated. In comparison with the one similar metagenomic study and several earlier culture-based ones, our findings change the current conception of the oral mycobiome, especially with the discovery of the high prevalence and abundance of the genus Malassezia. Previously identified as an important pathogen of the skin, and recently reported as the predominant fungal genus at the nostril and backs of the head and ear, this is the first account of Malassezia in the human mouth. Findings from this study were in good agreement with others on the existence of many consensus members of the core mycobiome, and on unique patterns for individual subjects. This research offered a cautionary note about unconditional acceptance of lengthy lists of community members produced by automated assignments, provided a roadmap for enhancing the likely biological relevance of sequence-based fungal surveys, and built the foundation for understanding the role of fungi in health and disease of the oral cavity.
authors.affiliation: Center for Applied Genetics and Technology and Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Dupuy
authors.affiliation: Center for Applied Genetics and Technology and Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Marika S
authors.initials: MS
authors.lastname: David
authors.affiliation: Center for Applied Genetics and Technology and Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Lu
authors.initials: L
authors.lastname: Li
authors.affiliation: Center for Applied Genetics and Technology and Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Heider
authors.affiliation: Center for Applied Genetics and Technology and Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Peterson
authors.affiliation: Center for Applied Genetics and Technology and Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Montano
authors.affiliation: Division of Periodontology Department of Oral Health and Diagnostic Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America.
authors.forename: Anna
authors.initials: A
authors.lastname: Dongari-Bagtzoglou
authors.affiliation: Division of Periodontology Department of Oral Health and Diagnostic Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America.
authors.forename: Patricia I
authors.initials: PI
authors.lastname: Diaz
authors.affiliation: Center for Applied Genetics and Technology and Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Linda D
authors.initials: LD
authors.lastname: Strausbaugh
mesh_terms: D066289:Data Curation; D030541:Databases, Genetic; D006801:Humans; D008290:Malassezia / Q000145:classification* / Q000502:physiology*; D009055:Mouth / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D009626:Terminology as Topic