Study on the horizontal transmission of oral Streptococcus mutans in day-nursery children / 华西口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To analyze genotypic diversity of oral Streptococcus mutans (S. mutans) and find out horizontal transmission possibility of the microbe in day-nursery children.</p><p><b>METHODS</b>The plaque samples were scratched with sterilized toothpicks from teeth of 32 day-nursery children aged between 3 and 4, then cultured on MSB plates. Clones with representative S. mutans-like were subcultured and identified to species level biochemically. AP-PCR fingerprinting was performed to distinguish genotypic diversity of those isolates. Then S. mutans isolated from different children with very similar amplicon profiles were examined by chromosomal DNA fingerprinting analysis.</p><p><b>RESULTS</b>S. mutans were isolated in oral cavities of 78.1% children, 100% in caries and 69.6% in caries-free children. A total of 57 genotypes were identified by AP-PCR. More than one amplitypes were identified in 88% of the 25 children with S. mutans colonization. Two pair of children shared common genotypic S. mutans.</p><p><b>CONCLUSION</b>There is no evident relation between number of genotype detected and caries. The presence of matching genotypes of S. mutans among day-nursery children suggests the horizontal transmission may exist.</p>