title: Molecular typing of Shigella sonnei isolates circulating in Nanjing, China, 2007-2011.
abstract: BACKGROUND
  Shigellosis is a major public health concern worldwide. This study intended to assess the baseline genotyping data among local Shigella sonnei strains spanning over five years.
  
  
  METHODS
  Fifty non-repeat clinical strains of S. sonnei isolated from stools of patients in different hospitals in Nanjing, China, were studied. Three subtyping tools, pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and multi-locus variable-number tandem-repeat (VNTR) analysis (MLVA), were used for routinely subtyping local S. sonnei.
  
  
  RESULTS
  DNA sequencing only identified two sequence types (STs) among the 50 isolates in the MLST profiles, whereas PFGE and MLVA both showed suitable discriminatory power and yielded 19 and 30 different patterns, respectively. The major PFGE pattern comprised 21 strains isolated from different years. A total of four complexes were identified by MLVA, with the isolates differing by a single locus (single-locus variants).
  
  
  CONCLUSIONS
  The S. sonnei strains circulating in Nanjing, China, in 2007-2011 originated from different clones with a degree of diversity. Most of the clones were closely related to each other. Overall, the strains were distinguishable by PFGE and MLVA. MLVA based on eight selected VNTR loci represented a more favorable degree of discrimination than did PFGE and may be a reliable complement for PFGE for routine subtyping of S. sonnei. The problems of MLST in subtyping regarding S. sonnei were also demonstrated.
authors.affiliation: Nanjing Center for Disease Prevention and Control, Nanjing, China. 404320141@qq.com.
authors.forename: Tingting
authors.initials: T
authors.lastname: Cheng
authors.forename: Xiaochao
authors.initials: X
authors.lastname: Shi
authors.forename: Wei
authors.initials: W
authors.lastname: Yong
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Xie
authors.forename: Jie
authors.initials: J
authors.lastname: Ding
mesh_terms: D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D004405:Dysentery, Bacillary / Q000453:epidemiology / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D005243:Feces / Q000382:microbiology; D014644:Genetic Variation; D005838:Genotype; D006761:Hospitals; D006801:Humans; D018598:Minisatellite Repeats; D058885:Multilocus Sequence Typing; D012764:Shigella sonnei / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial