Clonal Analysis of Severe Early Childhood Caries

Objectives: This study aimed to determine the microbiota of children with Severe Early Childhood Caries (S-ECC) compared to caries-free.

Methods: S-ECC and caries-free children (2-5 years) were recruited from medical centers serving families with low socioeconomic status. Interproximal molar bacterial samples were analyzed using PCR-cloning-sequencing to compare predominant species/phylotypes in S-ECC and caries-free children.

Results: Eight S-ECC and eight caries-free children (mean age 4.6 years, 73% male) were sampled. Average extend of caries was 5.8 teeth into dentin and 2.3 teeth into pulp. S-ECC children had mean PI 1.63, GI 1.98, and BOP 0.50. All caries-free children were born in the US compared to 63% with S-ECC. More parents of caries-free children had incomes >$40,000 annually (33% vs 0%) and had graduated from college (57% vs 13%) compared to S-ECC families. 1257 clones were processed, 623 from S-ECC. 465 clones from S-ECC yielded 54 identifications (>98% similarity) comprising 37 named species and 17 recognized phylotypes. 529 clones from caries-free samples yielded 61 identifications of 37 species and 24 phylotypes. Species most frequently detected in all children were Veillonella parvula, Streptococcus mitis, Selenomonas noxia, and Gemella haemolysans. Species/phylotypes most frequently detected from S-ECC included Streptococcus mutans, Streptococcus salivarius, S. mitis, Spaerocytophaga S3, Selenomonas artemidis, Neisseria sicca, and V. parvula. Species detected in caries-free children included Abiotrophia defective, Capnocytophaga sp., Eubacteria sp., Granulicatella sp., Streptococcus cristatus, Streptococcus gordonii, Streptococcus intermedius, Streptococcus oralis, and Streptococcus sanguinis. 25% S-ECC clones (n=158) and 17% caries-free clones (n=105), did not match named species and may include novel species/phylotypes.

Conclusions: PCR-cloning-sequencing detected differences in the microbiota of S-ECC and caries-free children. Higher proportions of S. mutans, other acid producing species, Neisseria sicca, V. parvula, and phylotype Spaerocytophaga S3 were detected in S-ECC compared to caries-free children.

Supported by NIDCR Grant DE-14264, T32 Grant DE007327-07 (EK).