Mutans Streptococci: maternal-child transmission confirmed by review


Mutans streptococci (MS) particularly Streptococcus mutans and Streptococcus sobrinus play a significant role in dental decay, although they are not the only cariogenic species present in oral biofilms.

The aim of this review was to determine whether there is scientific evidence of mother-to-child S. mutans transmission.


Searches were conducted in the PubMed and Cochrane Library databases. Observational studies in mother and child pairs where molecular analyses used to identify the presence of S. mutans transmission included bacteriocin typing, serotyping, ribotyping, AP-PCR, multilocus sequence typing (MLST), chromosomal DNA fingerprinting, and chromosomal DNA restriction fragment length polymorphism (RFLP) were considered. Two reviewers independently selected studies assessed quality and risk of bias and extracted data.


  • 36 studies using at least one genetic analysis of S. mutans were included
    • 13 studies applied AP- PCR;
    • 10 studies used DNA fingerprinting;
    • 8 bacteriocin typing;
    • 4 serotyping/ribotyping;
    • 1 Cnm PCR;
    • 2 MLST;
    • 1 RFLP;
    • 1 plasmid DNA;
    • and 11 used more than one technique.
  • 28 of the 36 studies had some biases
  • 13 studies reported a level of transmission of 70% or higher.
  • Transmission rates ranges from 52.5% – 84.5%
  • Meta-analysis of 19 studies found a cumulative event rate for maternal-child transmission of 0.650 (95% CI; 0.565 – 0.726).


The authors concluded:

Based on this systematic review and meta-analysis, we can conclude that there is scientific evidence of caregiver-to-child and, especially, mother-to-child S. mutans transmission, particularly when the mother is the primary caregiver. Additionally, it should be noted that there is a need for controlled longitudinal studies for a complete transmission evaluation assessment.


All the studies included in this review are observational and while there is some marked variation in the age groups of the included children (24 studies, the age groups were from 3 weeks to 3 years; 11 studies, 4 to 12 years, and in 1 study, 13 to 15 years) and a wide variation in the genetic techniques the studies all demonstrated maternal-child transmission to a greater or lesser extent. This is perhaps a not unexpected finding, although the interest lies in the fact that children whose teeth are colonized early by MS are thought to be at higher risk of caries.


da Silva Bastos VA, Freitas-Fernandes LB, Fidalgo TK, Martins C, Mattos CT, de Souza IP, Maia LC. Mother-to-child transmission of Streptococcus mutans: A systematic review and meta-analysis. J Dent. 2015 Feb;43(2):181-191. doi: 10.1016/j.jdent.2014.12.001. Epub 2014 Dec 6. Review. PubMed PMID: 25486222.

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