Molecular Analysis of Microbial Diversity in Advanced Caries

Abstract

Real-time PCR analysis of the total bacterial load in advanced carious lesions has shown that the total load exceeds the number of cultivable bacteria. This suggests that an unresolved complexity exists in bacteria associated with advanced caries. In this report, the profile of the microflora of carious dentine was explored by using DNA extracted from 10 lesions selected on the basis of comparable total microbial load and on the relative abundance of Prevotella spp. Using universal primers for the 16S rRNA gene, PCR amplicons were cloned, and approximately 100 transformants were processed for each lesion. Phylogenetic analysis of 942 edited sequences demonstrated the presence of 75 species or phylotypes in the 10 carious lesions. Up to 31 taxa were represented in each sample. A diverse array of lactobacilli were found to comprise 50% of the species, with prevotellae also abundant, comprising 15% of the species. Other taxa present in a number of lesions or occurring with high abundance included Selenomonas spp., Dialister spp., Fusobacterium nucleatum, Eubacterium spp., members of the Lachnospiraceae family, Olsenella spp., Bifidobacterium spp., Propionibacterium sp., and Pseudoramibacter alactolyticus. The mechanisms by which such diverse patterns of bacteria extend carious lesions, including the aspect of infection of the vital dental pulp, remain unclear.

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

“…In this study, 9 samples showed higher level of Olsenella. Another study conducted by Chhour et al in 2005 showed the presence of Olsenella in two samples. [20] Parascardovia and Scardovia belong to the family Bifidobacteriaceae, which was found to be 17.3% in this study.…”

“…Another study conducted by Chhour et al in 2005 showed the presence of Olsenella in two samples. [20] Parascardovia and Scardovia belong to the family Bifidobacteriaceae, which was found to be 17.3% in this study. Mantzourani et al demonstrated that Scardovia, and Parascardovia were associated with cavitated caries lesions, together with S. mutans, Lactobacilli, and yeasts, indicating that the acidic environment of the lesions provided a suitable habitat for the proliferation of these aciduric microorganisms.…”

Muramidases found in the foregut microbiome of the Tammar wallaby can direct cell aggregation and biofilm formation

“…et al, 2002;Hold et al, 2002;Eckburg et al, 2005;Zhongtang et al, 2005;Frank et al, 2007). Furthermore, culture-independent analysis identified Lachnospiraceae-affiliated bacteria to be present in the biofilms adherent to plant biomass recovered from ruminants (Zhongtang et al, 2005) and the oral cavity in humans (Chhour et al, 2005).…”

Fimbriae and lipopolysaccharides are necessary for co-aggregation between Lactobacilli and Escherichia coli

“…[1][2][3][4] Lactobacilli produce lactic acid, reducing the environmental pH, 5) and therefore, they can produce acidic environmental niches, such as the oral cavity. 6) Some studies showed that oral administration of Lactobacilli increased the levels of Lactobacilli in human feces and also decreased the numbers of fecal Escherichia coli and Anaerobic cocci. 7,8) These studies indicated that lower pH environment brought about by lactic acid could decrease the other bacteria such as Enterobacteriaceae.…”