DETECTION OF Streptococcus mutans IN PREDENTATE INFANTS

Objective: To establish the time of appearance of Streptococcus mutans (SM) in the oral cavity of healthy predentate infants. Methods: A descriptive observational cross sectional study was done. Samples of tongue dorsum, using sterilized swabs, were collected from 75 predentate, 1 to 7-month old infants that attended two low income health institutions in the city of Bucaramanga (Colombia). After inoculation and incubation typical morphotype colonies were isolated and identified by biochemical tests (sugar fermentation and catalase test). The presence or absence of SM was analyzed with the following variables: bottle feeding, maternal caries (dmft index), habits (kisses in the mouth of the baby) and the mode of delivery. Means, modes, medians and standard deviation were determined for all data. Bivariate analyses were performed by chi square test, Student's t test and Wilcoxon test. For all tests, p≤0.05 was considered statistically significant. Results: SM was detected in 15 (20%) of 75 predentate infants with a mean age of 4.1 ± 1.7 months. Out of the 15 mentioned before, 8 (53.3%) were bottle fed at night and the mothers of 13 (86.7%) presented dental caries. The only statistical and biologically significant variable found was kisses in the mouth, since 9 (60%) of the children in whom SM was detected were kissed in the mouth. Among infants who presented SM, 9 (60%) were vaginally delivered and 6 (40%) were delivered by caesarean section. Conclusion: Streptococcus mutans was found in the mouth prior to tooth eruption in 20% of the infants studied. The children who received kisses directly in their mouth registered a statistically greater association of presence of SM in oral cavity compared with the children that did not (p=0.01).