Site-Specific Profiling of the Dental Mycobiome Reveals Strong Taxonomic Shifts during Progression of Early-Childhood Caries.

Dental caries is one of the most common diseases worldwide. Bacteria and fungi are both commensals in the oral cavity; however, most research regarding caries has focused on bacterial impacts. The oral fungal mycobiome associated with caries is not well characterized, and its role in disease is unclear. ITS1 amplicon sequencing was used to generate taxonomic profiles from site-specific supragingival plaque samples (n = 82) obtained from 33 children with different caries status. Children were either caries free (CF), caries active with enamel lesions (CAE), or caries active with dentin lesions (CA). Plaque samples were collected from caries-free surfaces (PF) and from enamel (PE) and dentin (PD) lesions. Taxonomic profiles representing the different categorizations (CF-PF, CAE-PF, CAE-PE, CA-PF, CA-PE, and CA-PD) were used to characterize the mycobiome and its change through disease progression. A total of 139 fungal species were identified. Candida albicans was the most abundant species, followed by Candida dubliniensis We found that severely progressed plaque communities (CA-PD) were significantly different from healthy plaque communities (CF-PF). A total of 32 taxa were differentially abundant across the plaque categories. C. albicans, C. dubliniensis, Nigrospora oryzae, and an unclassified Microdochium sp. were correlated with caries, whereas 12 other taxa were correlated with health. C. dubliniensis increased steadily as caries progressed, suggesting that C. dubliniensis may play an important role in caries pathogenicity. In contrast, four health-associated fungal taxa have the potential to antagonize the cariogen Streptococcus mutans via xylitol production, suggesting a possible fungal mechanism that could contribute to maintenance of dental health.IMPORTANCE Early-childhood caries is one of the most prevalent diseases in children worldwide and, while preventable, remains a global public health concern. Untreated cavities are painful and expensive and can lead to tooth loss and a lower quality of life. Caries are driven by acid production via microbial fermentation of dietary carbohydrates, resulting in enamel erosion. While caries is a well-studied disease, most research has focused on bacterial impacts, even though fungi are commensal organisms living within the plaque biofilm. There is very little known about how fungi impact caries pathogenicity. The elucidation of fungal taxa involved in caries disease progression is necessary for a more holistic view of the human oral microbiome. Data from this study will improve our understanding of how the fungal community changes as disease progresses and provide insight into the complex etiology of dental caries, which is necessary for the development of treatment plans and preventative measures.