Molecular typing of Shigella sonnei isolates circulating in Nanjing, China, 2007–2011

  • Tingting Cheng Nanjing Center for Disease Prevention and Control, Nanjing, China
  • Xiaochao Shi Nanjing Center for Disease Prevention and Control, Nanjing, China
  • Wei Yong Nanjing Center for Disease Prevention and Control, Nanjing, China
  • Jianping Wang National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
  • Guoxiang Xie Nanjing Center for Disease Prevention and Control, Nanjing, China
  • Jie Ding Nanjing Center for Disease Prevention and Control, Nanjing, China
Keywords: Shigella sonnei, molecular typing, PFGE, multi-locus sequence typing, multi-locus variable-number tandem-repeat

Abstract

Introduction: 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.

Methodology: 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.

Author Biographies

Tingting Cheng, Nanjing Center for Disease Prevention and Control, Nanjing, China
Department of Microbiology
Xiaochao Shi, Nanjing Center for Disease Prevention and Control, Nanjing, China
Department of Microbiology
Wei Yong, Nanjing Center for Disease Prevention and Control, Nanjing, China
Department of Microbiology
Jianping Wang, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
State Key Laboratory for Infectious Disease Prevention and Control
Jie Ding, Nanjing Center for Disease Prevention and Control, Nanjing, China
Chief of  Department of Microbiology
Published
2014-12-15
How to Cite
1.
Cheng T, Shi X, Yong W, Wang J, Xie G, Ding J (2014) Molecular typing of Shigella sonnei isolates circulating in Nanjing, China, 2007–2011. J Infect Dev Ctries 8:1525-1532. doi: 10.3855/jidc.4933
Section
Original Articles