Insights into the Virulence Traits of <b><i>Streptococcus mutans</i></b> in Dentine Carious Lesions of Children with Early Childhood Caries

Abstract

Streptococcus mutans is an oral bacterium considered to play a major role in the development of dental caries. This study aimed to investigate the prevalence of S. mutans in active and arrested dentine carious lesions of children with early childhood caries and to examine the expression profile of selected S. mutans genes associated with survival and virulence, within the same carious lesions. Dentine samples were collected from 29 active and 16 arrested carious lesions that were diagnosed in preschool children aged 2-5 years. Total RNA was extracted from the dentine samples, and reverse transcription quantitative real-time PCR analyses were performed for the quantification of S. mutans and for analyses of the expression of S. mutans genes associated with bacterial survival (atpD, nox, pdhA) and virulence (fabM and aguD). There was no statistically significant difference in the prevalence of S. mutans between active and arrested carious lesions. Expression of the tested genes was detected in both types of carious dentine. The pdhA (p = 0.04) and aguD (p = 0.05) genes were expressed at higher levels in arrested as compared to active lesions. Our findings revealed that S. mutans is part of the viable microbial community in active and arrested dentine carious lesions. The increase in expression of the pdhA and aguD genes in arrested lesions is likely due to the unfavourable environmental conditions for microbial growth, inherent to this type of lesions.

Probiotic Lactobacillus sp. inhibit growth, biofilm formation and gene expression of caries‐inducing Streptococcus mutans

“… Production of acid that damages dental hard tissues ; An agmatine deiminase system and F‐ATPase encoded by the aguBDAC operon and atpD gene , which are major components in acid‐adaptive response that contribute to the aciduric characteristics. The ability to synthesize exopolysaccharides (EPS) from sucrose by the action of multiple glucosyltransferases (Gtfs) encoded by the genes gtfb , gtfc , gtfd , in addition to fructosyltransferase encoded by sacB (ftf ) gene. The glucosyltransferase and fructosyltransferase enzymes catalyse the synthesis of extracellular glucan and fructan polymers from sucrose, respectively .…”

“…(ii) An agmatine deiminase system and F-ATPase encoded by the aguBDAC operon [9] and atpD gene [10], which are major components in acid-adaptive response that contribute to the aciduric characteristics. (iii) The ability to synthesize exopolysaccharides (EPS) from sucrose by the action of multiple glucosyltransferases (Gtfs) encoded by the genes gtfb, gtfc, gtfd, in addition to fructosyltransferase encoded by sacB (ftf) gene.…”

Correlation between dental caries experience and the level of Streptococcus mutans and lactobacilli in saliva and carious teeth in a Yemeni adult population

“…The lesion in each tooth was excavated, suspended in alcohol, and kept at − 20 °C until use. One gram of the carious dentine fragment was weighed and initially dispersed manually by vortexing for 20 s prior to extraction of bacterial DNA [11,12].…”

Extraction and purification of RNA from human carious dentine: an approach to enable bacterial gene expression studies

“…The majority of RNA-based investigations of oral microbiota analyzed only planktonic cells 4 , in vitro biofilms 5,6,7 or in vivo biofilms from rodent animals 8,9 . Although the first transcriptomic studies of human dental biofilm 10,11 and dentine 12,13 were carried out, just a few articles showed is given about technical procedures, RNA yield, purity and integrity from these human samples studies 13,14 . Besides, more attention has been requested about transcriptional studies in human dentinal caries, which can reflect the behavior of cariogenic bacteria in loco 2 .…”