title: [Study on the horizontal transmission of oral Streptococcus mutans in children].
abstract: OBJECTIVE
  To find out horizontal transmission of oral Streptococcus mutas (S. mutans) in nursery children through analyzing the similarity of S. mutans genotypes.
  
  
  METHODS
  The study group included 24 nursery children between 3 and 4 years of age. Dental plaque samples were collected with sterile toothpick and cultured on MSB plates for 48 h. Individual Streptococcus mutans group colonies representative of the colonial morphologies were subcultured on TPY plates. These strains were identified to species level biochemically. AP-PCR fingerprinting was preformed after identification. S. mutans isolates from different children with very similar fingerprinting profiles were examined by chromosomal DNA fingerprinting analysis.
  
  
  RESULTS
  Streptococcus mutans group were isolated in oral cavities of 66.7% children, 58.3% in caries-free and 75.0% in caries children. A total of 4' S. mutans isolates from 24 subjects were analyzed by AP-PCR, and 29 different amplitypes were identifyied, 45.8% carried tw. genotypes. There were 2 genotypes of S. mutans isolated repeatedly among 12 nursery children.
  
  
  CONCLUSIONS
  The presence of matching genotypes of S. mutans among nursery children suggests horizontal transmission.
authors.affiliation: Study on the horizontal tranission of Oral Streptococcus mutans in children.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Ran
authors.initials: R
authors.lastname: Shang
authors.forename: Jun-qi
authors.initials: JQ
authors.lastname: Ling
authors.forename: Xue-dong
authors.initials: XD
authors.lastname: Zhou
mesh_terms: D002675:Child, Preschool; D003731:Dental Caries; D003773:Dental Plaque; D005838:Genotype; D006801:Humans; D016133:Polymerase Chain Reaction; D013295:Streptococcus mutans