title: [A study on genetic polymorphism of rRNA gene pattern of Vibrio cholerae O139 in China].
abstract: OBJECTIVE
  To investigated the genetic polymorphism of the isolated strains using ribotyping method.
  
  
  METHODS
  One hundred twenty-two strains of V. cholerae O139 isolated from different areas of China from 1993 to 1999 were selected and characterized with ribotyping, including 16s rDNA and 23s rDNA probes.
  
  
  RESULTS
  One hundred twenty-two strains were differentiated into 10 different ribotypes (RT1-RT10) on the basis of rRNA gene probes hybridization (with Bgl I digestion), which consisted of 7 - 9 bands between 12 and 1.5 kb in size. RT1 and RT3, as two predominant ribotypes, comprised most number of the strains which spread to the extensive range. Nine strains, which are negative to ctxAB, zot and RS individually, belong to 4 special ribotypes. The dendrogram revealing genetic relationship among different clones of V. cholerae O139 showed that the clones belonging to RT1 and RT2 had genetic similarity on high degree, although they were isolated from different regions. The two predominant ribotypes (RT1 and RT3) were distant in genetic relationship.
  
  
  CONCLUSIONS
  Results showed the clonal diversity and the wide area distribution of V. cholerae O139 strains in China, suggesting the multiple origins of O139 epidemics.
authors.affiliation: Priority Laboratory of Molecular Medical Bacteriology of Ministry of Health, Institute for Infectious Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Qu
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
authors.forename: Guoming
authors.initials: G
authors.lastname: Qi
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Liu
authors.forename: Shouyi
authors.initials: S
authors.lastname: Gao
mesh_terms: D010802:Phylogeny; D011110:Polymorphism, Genetic; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012338:RNA, Ribosomal, 23S / Q000235:genetics*; D021521:Ribotyping; D013045:Species Specificity; D041242:Vibrio cholerae O139 / Q000145:classification / Q000235:genetics*
chemical_list: D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S