Streptococcus sobrinus and Streptococcus mutans in a Longitudinal Study of Dental Caries

Abstract

Mutans streptococci have been correlated with human dental caries. Much is known about the role of Streptococcus mutans in the caries process, but the role of S. sobrinus is less clear. This bacterium has been reported to be very acidogenic and aciduric in vitro and cariogenic in rats and should, therefore, have at least some cariogenic potential in humans. This study was aimed at determining the possible relationship between S. sobrinus, S. mutans and dental caries in a longitudinal study by using a non-selective culturing method and species-specific monoclonal antibodies. At the beginning of this study, 158 children aged 4 yr were examined clinically and salivary mutans streptococci were counted on MSB agar. At 5 and 6 yr of age, the children were examined and mutans streptococci were detected by using speciesspecific monoclonal antibodies and MSB agar. The carriage rate of S. sobrinus increased between 5 and 6 yr from 25 to 48 per cent. The presence of this microorganism was significantly associated with canes incidence (P=O.O3). Relationships between the presence of S. sobrinus and salivary pH, buffer capacity or flow rate were not found. The presence of S. sobrinus or S. mutans was not significantly correlated with dmft when using the species-specific monoclonal antibodies. However, this correlation was highly significant (P < 0.001) when the mutans streptococci were detected by using the selective medium MSB. This suggests that differences in cariogenic potential occur within the species S. mutans or S. sobrinus. The present longitudinal study indicates that S. sobrinus is correlated with caries incidence, but its role in the initiation of caries could not be ascertained.

How Has Genomics Altered Our View of Caries Microbiology?

“…Sobrinus is the Latin for 'cousin' and S. sobrinus remains the poor country cousin to S. mutans . Molecular detection methods are in agreement with earlier cultural studies in showing that S. sobrinus is carried by a minority of people, and while a number of studies have found that children with high caries activity are more likely to carry high levels of both S. mutans and S. sobrinus , a role for S. sobrinus in the initiation stage of caries has not been established [de Soet et al, 1993;Tanzer et al, 2001;Okada et al, 2005;Rupf et al, 2006]. This is somewhat paradoxical, since in terms of the range of characteristics generally considered to contribute to the virulence of MS, S. sobrinus strains are generally more potent than S. mutans strains: they are more cariogenic in rats, produce more acid, are more acid tolerant and show stronger sucrose-dependent adherence.…”

Lactobacillus reuteri BM53-1 Produces a Compound That Inhibits Sticky Glucan Synthesis by Streptococcus mutans

“…The tooth surface is coated by a thin layer, called a pellicle, that consists of many proteins contained in saliva [ 4 , 5 , 6 , 7 ]. Streptococcus ( S. ) mutans and S. sobrinus , which are known as cariogenic bacteria, produce insoluble and adhesive glucans from sucrose in the oral cavity [ 8 , 9 , 10 ]. These bacteria adhere to the tooth surface through the van der Waals force between the early colonizers of dental plaque that nonspecifically adhere to the pellicle layer [ 11 , 12 ].…”