Candida albicans profiling in children with severe early childhood caries

Zhenting Xiang

Xiang, Zhenting, Liu, Yuan, Koo, Hyun
University of Pennsylvania School of Dental Medicine, Biofilm Research Labs, Levy Center for Oral Health; Department of Orthodontics


Candida albicans is an opportunistic fungal organism frequently detected in dental plaque (biofilm) from children with severe early childhood caries (S-ECC). Clinical isolates of C. albicans from different body sites exhibit different genetic and phenotypic properties. However, information about the variability of C. albicans isolated from plaque remains sparse. Here, we aimed to characterize the traits of C. albicans isolates from S-ECC plaque and their cariogenic properties within biofilms.


A total of 16 C. albicans were isolated from S-ECC dental plaque. The genetic relatedness of C. albicans isolates was assessed, and compared with reference strain 529L (isolated from oral mucosa) using multi-locus sequence typing. Spot assays were performed to examine the phenotypic characteristics of C. albicans isolates. Biofilm related factors including hyphal formation, secreted aspartyl protease activity, aciduricity and acidogenicity, and GtfB binding ability were tested. The cross-feeding effect of C. albicans isolates and S. mutans was evaluated by sucrose assimilation assay. High-resolution confocal imaging and real-time pH monitoring in saliva were employed to analyze the 3D architecture and acidogenic capacity of cross-kingdom biofilm.


C. albicans S-ECC isolates exhibited a broad range of genotypic and phenotypic variations, including strains with higher resistance to oxidative stress and antifungal agent while some were devoid of hyphal forms. C. albicans isolates were acidogenic and aciduric, whereas some strains demonstrated enhanced growth under sucrose compared to reference strain 529L, suggesting adaptation in plaque environment. Moreover, all C. albicans isolates promoted the development of robust mixed-biofilm with S. mutans, even those that were defective of hyphal formation. Notably, the presence of C. albicans enhanced biofilm acidogenicity, helping maintain highly acidic pH (<5.5) in the presence of buffering saliva.


Our results demonstrate that C. albicans strains isolated from S-ECC plaque exhibit several cariogenic traits and mutualistic interactions with S. mutans, suggesting adaptation to the microenvironment on the tooth surface while influencing the biofilm virulence potential associated with a severe form of dental caries.