Genotype profiles of Lactobacilli from American Indian Children and their Association with Caries

Objectives: Early childhood caries (ECC) is a debilitating oral disease that demands the attention and awareness of the general public, dental professionals, and researchers, alike. Unfortunately, American Indians and Alaska Natives have been noted as the two racial groups with the highest rates of early childhood caries. We are currently investigating the presence of lactobacillus and the spectrum of genotypes of lactobacilli in American Indian children from the Northern Plains Tribal Community. We report here on the number of lactobacillus genotypes per subject, the number of isolates per genotype, and the number of subjects per lactobacillus genotype. This data and the dmfs scores of these children (in our study database) will be compared against children of the same demographic without lactobacillus.
Methods: Whole mouth plaque samples were collected from AI mothers and children. Samples were plated on two Rogosa agar plates for each respective concentration to determine whether lactobacillus was present. After this, DNA extraction from each colony and genotyping of the isolates was determined by using an arbitrary primed PCR approach (AP-PCR). Genotypic diversity was assessed by generation of dendograms using GelCompar ^®IIv6.5 software (Applied Maths, Austin, TX, USA). Curve based cluster analysis (1% optimization, 1% curve smoothing) using the Pearson correlation and Unweighted Pair Group Method using Arithmetic Averages (UPGMA) was used to assess strain relatedness. Lactobacilli isolates displaying greater than 70% similarity were considered to be the same genotype.
Results: Of the 20 PCR gels examined, we compared each strain of lactobacillus and their respective isolate looking for any similarity greater than 70%. With each genotype of lactobacillus, the top comparison of each strain was then compared against all the other strains.
Conclusions: We observed significant differences in disease burden in children based on the mother’s lactobacillus status.