IJMEG Copyright © 2010-present. All rights reserved. Published by e-Century Publishing Corporation, Madison, WI 53711
Int J Mol Epidemiol Genet 2012;3(4):321-332

Original Article
Multi-Locus Sequence Typing (MLST) and Repetitive Extragenic Palindromic
Polymerase Chain Reaction (REP-PCR), characterization of shigella spp. over
two decades in Tianjin China

Yang Cao, Dianjun Wei, Idrissa L kamara, Wei Chen

Department of Clinical Laboratory, Second Hospital of Tianjin Medical University, Tianjin 300211, China; Department
of Infectious disease, Second Hospital of Tianjin Medical University, Tianjin 300211, China

Received November 8, 2012; Accepted October 23, 2012; Epub November 15, 2012; Published November 30, 2012

Abstract: To understand the change of the dominant serogroup of Shigella spp., their antimicrobial resistance over
more than two decades in Tianjin, their phylogenetic similarity and to determine their evolutionary biology by using
REP-PCR and MLST in order to study their epidemiological character. Multi-locus Sequence Typing was performed
to determine their lineage and phylogenetic similarity. REP-PCR typing was used to study the homology of their genomic
DNA. The isolated rate of group D Shigella in 2009 and 2010 had obviously increased. Antimicrobial susceptibility
test results showed that the resistant rates of the 1981-1983 Shigella flexneri to tetracycline, streptomycin
and chloramphenicol varied from 76.47 to 100%, they were all sensitive to other antibiotics. During 2009-2010, the
resistance rates of the isolated Shigella flexneri to gentamicin, amikacin, third and fourth Generation Cephalosporins
and quinolones had increased. MLST results produced five sequence types and two sequence type complexes.
REP-PCR showed DNA band similarities between the 1981-1983 and 2009-2010 strains. The dominant serogroup
of Shigella in Tianjin has changed from Shigella flexneri to Shigella sonnei. Increased drug resistance of Shigella flexneri
is higher than Shigella sonnei because a great variety of antibiotics has been used. The MLST results showed
that the 1981-1983 strains had the same sequence type with some of the 2009-2010 strains. Combination of
MLST and REP-PCR produced better discriminatory power than using either method alone. (IJMEG1111001).

Keywords: Shigella, multidrug resistance, REP-PCR, multi-locus sequence typing

Address all correspondence to:
Dr. Dian-Jun Wei
300211 Tianjin, 23 Ping Jiang Road
Department of Clinical Laboratory
Second Hospital of Tianjin Medical University
Tianjin 300211, China.
Phones: office: +86-2288328930
Mobile: +86-13370336366; Fax: +86-2223542586
E-mail: weidianjun@gmail.com