Association of Candida albicans and Streptococcus mutans With ECC Recurrence

Objectives: Our main objective is to investigate the association of Streptococcus mutans and Candida albicans with recalcitrant infections that result in high rates of early childhood caries (ECC) recurrence. ECC relapse occurs in 25-40% of children typically within one year of treatment. There is a strong synergistic association between S. mutans and Candida albicans with caries. Thus, co-infection with S. mutans and C. albicans results in bacterial-yeast aggregation during biofilm development, mutual nutritional benefits and reduced oxygen tension that can contribute to caries development and severity.
Methods: In this cross-sectional clinical study, we collect saliva and dental plaque from children ages 6 to 60 months who are: i) caries-free (CF), ii) treated for ECC with no signs of relapse within 6 months (CE-NR), and iii) treated for ECC and relapsed within 6 months (CR). Samples are quantified for total bacteria, S. mutans and Candida sp. S. mutans-like colonies were differentiated by PCR whereas yeast-like colonies were differentiated by chomogenic agar.
Results: Of the sixty patients enrolled to date, CR and CE-NR subjects had higher counts of S. mutans in saliva compared to CF subjects, while in plaque, CR subjects had significantly higher counts of S. mutans than both CF and CE-NR subjects. S. mutans was detected by PCR in 19% of CF patients while CE-NR and CR had >90% detection. Additionally, CR subjects had significantly higher counts of Candida sp. in saliva than CF and CE-NR subjects. In plaque, CR and CE-NR had significantly higher counts of Candida sp. than CF subjects. C. albicans was present in 75% of CR subjects while present in 29% and 42% of CF and CE-NR subjects, respectively.

Conclusions: Candida albicans and S. mutans appear to be intimately associated with caries recurrence, contributing to the establishment of recalcitrant biofilms.