Transmission of mutans streptococci in mother-child pairs.

BACKGROUND & OBJECTIVES: Dental caries is an infectious, transmissible disease. Maternal transfer of mutans streptococci (MS) has been a subject of research. The aim of this study was to evaluate the transmission of MS from mother to children through genetic analysis.

METHODS: Thirty mother-child pairs were included and divided into three groups according to the age of the children. Saliva samples were collected and MS colonies from each mother-child pair were isolated. After inoculation and incubation, MS colonies were submitted to amplification technique by polymerase chain reaction (PCR) for identification and arbitrarily primed PCRs (AP-PCRs) to determine various MS genotypes.

RESULTS: From birth to six months of age, 30 per cent of children exhibited MS colonization, and by the age of 30 months, 100 per cent harboured the bacteria (P < 0.001). Factors associated with MS colonization were eruption of teeth (P < 0.001), feeding habits with mean colony count being significantly lower in breast-fed as compared to bottle-fed children (P < 0.001) and a significant association between mean MS count of child and mother's practice of sharing spoon with child (P < 0.001). The AP-PCR fingerprinting profile analysis showed 17 MS groups (clusters) containing identical or highly related isolates in mother-child pairs with a high level of similarity (77.27 %).

INTERPRETATION & CONCLUSIONS: The presence of matching MS genotypes suggested vertical transmission from mothers to children. Feeding habits, gum cleaning and number of erupted teeth in children had significant effect on MS colonization. There is a need to develop strategies to present MS colonization in children.