title: [Study of the plasmid profiles and geographical distribution of Yersinia pestis in China].
abstract: OBJECTIVE
  To analyze the plasmid features and geographical distribution characteristics of Yersinia pestis of different plague foci in China.
  
  
  METHODS
  A total of 2 213 Yersinia pestis strains were colected from 11 Chinese plague foci separated during 1943 to 2012, and plasmid DNA according to alkali cracking method, and measured the relative molecular mass (Mr) of plasmid DNA based on the standard plasmid contrast method, then analyzed the plasmid profiles by agar gel electrophoresis.
  
  
  RESULTS
  A total of 2 213 strains had 16 kinds of plasmids with different Mr, including 4×10(6), 6×10(6), 7×10(6), 13×10(6), 16×10(6), 20×10(6), 22×10(6), 23×10(6), 27×10(6), 30×10(6), 36×10(6), 45×10(6), 52×10(6), 65×10(6), 72×10(6) and 90×10(6). Plasmid were classified into 26 kinds of plasmid profiles. A total of 2 213 Yersinia pestis strains contained 4 large plasmids, 52×10(6), 65×10(6), 72×10(6) and 90×10(6), whose ratio was 22.10% (589/2 213), 75.60% (1 672/2 213), 0.17% (4/2 213), 2.12% (47/2 213), respectively. Among which, strains with plasmid 52×10(6), 65×10(6), 90×10(6) distributed in Qinghai-Tibet plateau Himalayan Marmot natural plague foci, strains with 72×10(6) plasmid only distributed in Inner Mongolia Meriones unguiculatus natural plague foci and Junggar Basin R. opimus natural plague foci, and 65×10(6) plasmid distributed in all the other foci.
  
  
  CONCLUSIONS
  Strains in Chinese 11 plague foci contained 4 kinds of large plasmid, the Mr respectively were 52×10(6), 65×10(6), 72×10(6), 90×10(6), which were classified into 26 kinds of plasmid profiles with other plasmid. These plasmid profiles distributed in relatively independent epidemic focus.
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Youquan
authors: Y
authors: Xin
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Baiqing
authors: B
authors: Wei
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Xiaoyan
authors: X
authors: Yang
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Rongjie
authors: R
authors: Wei
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Meiying
authors: M
authors: Qi
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Haoming
authors: H
authors: Xiong
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Juan
authors: J
authors: Jin
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Cunxiang
authors: C
authors: Li
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Xiang
authors: X
authors: Li
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China.
authors: Zuyun
authors: Z
authors: Wang
authors: Plague Prevention and Control Department, Qinghai Institute for Endemic Diseases Prevention and Control, Xining 811602, China. Email: drx200907@163.com.
authors: Ruixia
authors: R
authors: Dai
mesh_terms: D000818:Animals; D002681:China; D005838:Genotype; D010930:Plague; D010957:Plasmids; D015010:Yersinia pestis