The Factors Associated with Early Colonization of Mutans Streptococci in Infants

Objectives: The purpose of this study was to determine the early colonization of mutans streptococci (MS) and the factors associated with the early colonization of MS in infants.

Material and Methods: A prospective cohort study was conducted. The subjects were 228 pairs of caregivers and infants aged 5-7 months who came to healthcare centers/ hospitals for vaccination in Songkhla and Yala provinces. The saliva and plaque samples were collected by sterile cotton swab from oral cavity of infants at baseline (T0) and 6 to 9 months after that (T2) and from caregivers at T0. The caregivers were interviewd at T0 and T2, and were examined for plaque and dental caries score (WHO criteria) at T0.

Results: The percentage of infants with MS colonization were 2.2% at aged 5-7 months and 42.3% at aged 11-16 months. Mutans streptococci colonization was found in 1.8% of predentate infants. The study found no associations between associated factors and MS colonization in infants aged 5-7 months. However, family income (p=0.017), sweet beverage consumption (p=0.038), sleep with a bottle (p=0.003), breast feeding (p=0.043) and caregiver’s tooth decay (p=0.015) were significantly associated with colonization of MS in infants aged 11-16 months. In the final model of multivariable logistic regression, number of erupted teeth in the mouth, caregiver mutans streptococci level (>100 CFU/ 1.5 cm²) and type of milk consumption were statistically significantly associated with MS presence in oral cavity of infant aged 11-16 months.

Conclusion: High level MS of caregiver, type of milk consumption and more erupted teeth in infant were associated with MS early colonization in infants.