Anaerobic Cultural Microbiota of Severe Early Childhood Caries

Objectives: Severe early childhood caries (S-ECC) is a major problem in disadvantaged populations. Recently selective culture and molecular approaches have characterized this infection. Cultural methods provide strains for pathogenicity assessment. This study aimed to evaluate the microbiota of S-ECC using enriched and selective anaerobic culture.

Methods: S-ECC and caries-free (CF) children (2-5 years) were recruited from Boston Medical Center. Samples from incisors, molars and the tongue were cultured on blood (pH 7), selective acidic (pH 5), and TYCSB S. mutans agars and analyzed by PCR to S. mutans (Sm). Isolates were characterized using 16S rRNA partial sequencing and compared with phylotypes (species) in the Forsyth Human Oral Microbiome Database.

Results: Over 1400 isolates were sequenced from 18 S-ECC children and 13 CF children. S. mutans was detected in CF and S-ECC children from blood 0%, 45%; acid 33%, 71%; TYCSB 42%, 82%; and Sm PCR 18%, 63% respectively. Growth of most species was enhanced on blood compared to selective media. Comparing blood and acid agars, Parascardovia denticolens, Lactobacillus fermentum, and S. sobrinus were detected only on acid agar from S-ECC children. Additional species on acid media from S-ECC included S. mutans, S. anginosus, and an unidentified Scardovia. Species from CF children included S. salivarius, an unnamed Actinomyces, Eubacterium saburreum, E. corrodens, Streptococcus parasanguinis, and 3 unnamed Actinomyces. The majority of species cultivated on blood media were detected in S-ECC and CF children, including named and unnamed Selenomonas, Prevotella, Campylobacter, Capnocytophaga, and F. nucleatum.

Conclusions: The microbiota of S-ECC included recognized and unnamed species. S. mutans was detected most frequently on TYCSB agar. The acidic agar selected for several caries associated species. Anaerobic culture of S-ECC detected new putative cariogenic pathogens. Supported by NIH/NIDCR Grant DE-015847