title: [Preliminary study on genotypic diversity of Streptococcus mutans in Xinjiang Uygur preschool children].
abstract: OBJECTIVE
  To investigate the relationship between genotypic diversity of Streptococcus mutans (Sm) and deciduous teeth caries in Xinjiang Uygur autonomous region.
  
  
  METHODS
  Isolates of Sm were obtained from 17 caries-free and 17 caries-active Uygur preschool children aged from 3 to 5 years. A total of 143 isolates were subcultured, biochemically characterised and identified by polymerase chain reaction (PCR) as Sm and Streptococcus sobrinus (Ss). Then the Sm isolates were genotyped by arbitrarily primed-PCR (AP-PCR).
  
  
  RESULTS
  A total of 81 Sm isolates from caries-active subjects and 62 isolates from caries-free subjects were identified by PCR and forty distinct genotypes identified from 143 clinical isolates. In seventeen caries-active group, 9 children had only 1 genotype, 5 children had 2 genotypes, 3 children had 3 genotypes. In seventeen caries-free group, 14 children had only 1 genotype, 3 children had more than 2 genotypes. The Spearman correlation test showed a strong association between genotypic diversity and caries experience (r = 0.342, P < 0.05).
  
  
  CONCLUSIONS
  Isolates of Sm in caries-active Uygur preschool children show apparent more genetic diversity than those in caries-free children. The genotypes of isolates might be related to differences in caries susceptibility.
authors: Department of Cariology Endodontology and Operative Dentistry, Xinjiang Medical University, Urümqi 830054, China.
authors: Jing
authors: J
authors: Lin
authors: Jin
authors: J
authors: Zhao
authors: Munammetemin
authors: M
authors: Nurbiye
authors: Xin-shang
authors: XS
authors: Li
mesh_terms: D002675:Child, Preschool; D002681:China / Q000208:ethnology; D003731:Dental Caries / Q000208:ethnology / Q000382:microbiology*; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D016133:Polymerase Chain Reaction; D013295:Streptococcus mutans / Q000235:genetics* / Q000302:isolation & purification; D016986:Streptococcus sobrinus / Q000302:isolation & purification