Molecular Analysis of Bacterial Species Associated with Childhood Caries

Abstract

Although substantial epidemiologic evidence links Streptococcus mutans to caries, the pathobiology of caries may involve more complex communities of bacterial species. Molecular methods for bacterial identification and enumeration now make it possible to more precisely study the microbiota associated with dental caries. The purpose of this study was to compare the bacteria found in early childhood caries (ECC) to those found in caries-free children by using molecular identification methods. Cloning and sequencing of bacterial 16S ribosomal DNAs from a healthy subject and a subject with ECC were used for identification of novel species or uncultivated phylotypes and species not previously associated with dental caries. Ten novel phylotypes were identified. A number of species or phylotypes that may play a role in health or disease were identified and warrant further investigation. In addition, quantitative measurements for 23 previously known bacterial species or species groups were obtained by a reverse capture checkerboard assay for 30 subjects with caries and 30 healthy controls. Significant differences were observed for nine species: S. sanguinis was associated with health and, in order of decreasing cell numbers, Actinomyces gerencseriae, Bifidobacterium, S. mutans, Veillonella, S. salivarius, S. constellatus, S. parasanguinis, and Lactobacillus fermentum were associated with caries. These data suggest that A. gerencseriae and other Actinomyces species may play an important role in caries initiation and that a novel Bifidobacterium may be a major pathogen in deep caries. Further investigation could lead to the identification of targets for biological interventions in the caries process and thereby contribute to improved prevention of and treatment for this significant public health problem.

Streptococcus mutans: a new Gram-positive paradigm?

“…It is widely recognized that the different interactions, synergistic or antagonistic, between members of these complex communities can shift the bacterial population from health to disease. This is particularly true for the oral cavity, where S. mutans, among other less wellcharacterized lactic acid-producing bacteria such as lactobacilli and bifidobacteria, tends to dominate the oral flora as caries progresses (Becker et al, 2002;Gross et al, 2010;Tanner et al, 2011a, b). As proposed by Marsh (1994) in the ecological plaque hypothesis, dental caries is a disease that results from a shift in the proportions of the resident flora as a consequence of changes in the environment (e.g.…”

Association of oral streptococci community dynamics with severe early childhood caries as assessed by PCR-denaturing gradient gel electrophoresis targeting the rnpB gene

“…S. sanguinis and S. gordonii are pioneering bacteria that colonize tooth surfaces and form dental plaques on tooth surfaces that are free of caries (Becker et al, 2002;Gross et al, 2010). S. sanguinis competes with other bacteria by producing a bacteriocin or excreting hydrogen peroxide to trigger the lysis of competitors during initial colonization (Kreth et al, 2008).…”

Cariogenic microflora and pH in superficial and deep layers of occlusal carious lesions - A metagenomic analysis

“…[11] The size and thickness of the lesion was also correlated with the initial pH. [12,13] The etiology of caries being multifactorial, there is evidence of carious lesions developing in the absence of S. mutans. With the advent of new technology in the world of molecular microbiology, it has been proven that numerous novel bacteria other than S. mutans have been isolated from the carious dentin.…”