Acquisition of Streptococcus mutans and cell adherence among 2-year old children with different caries experience

Objective To explore the acquisition and the sucrose-dependent cell adhesive ability of Streptococcus mutans in dental plaque of 2-year old children. Methods A total of 32 caries-active (dmft ≥ 5) children and 32 caries-free (dmft = 0) children were selected. Clinical isolates were identified by colony morphology and biochemical tests. Spectroscopic turbidity method was used to analyze the sucrose-dependent cell adherence to glass wall of the sucrose-containing testing tubes. Results Acquisition of Streptococcus mutans was 56.25% in 64 children. Acquisition in caries-active children was significantly higher than in caries-free children (75.00% v.s. 37.50%,P 0.01). The isolated Streptococcus mutans strains were 75 strains from caries-active group and 34 strains from caries-free group. The average adhesive ratio of the Streptococcus mutans strains isolated from caries-active group was (0.58 ± 0.15) in the 1% sucrose-containing culture medium,a little higher than from caries-free group(0.56 ± 0.13),but the difference had no statistical significance. Conclusion The results suggest that in caries-active children of 2 years old the acquisition of Streptococcus mutans is related to high incidence of caries,but the sucrose-dependent cell adherence ability has no effect on high incidence of caries.