title: Wide dissemination of multidrug-resistant Shigella isolates in China.
abstract: OBJECTIVE
  To evaluate the prevalence of antimicrobial resistance and selected antimicrobial resistance mechanisms in Shigella isolates recovered in outpatients from 1997 to 2009 in China.
  
  
  METHODS
  The isolates were subjected to serotyping and antimicrobial susceptibility testing. Shigella isolates producing extended-spectrum β-lactamases (ESBLs) or resistance to ciprofloxacin were further characterized by PFGE to determine the genetic relatedness. These isolates were also screened for β-lactamase genes and mutations in the quinolone resistance-determining regions (QRDRs) by PCR. DNA sequence analysis was also performed.
  
  
  RESULTS
  After serotyping, 301 Shigella isolates were grouped into three subgroups and 13 distinct serotypes. The antimicrobial resistance profiles differed among subgroups and serotypes. Ciprofloxacin-resistant isolates were mainly Shigella flexneri serotypes f2a and f4a, which were resistant to at least four additional non-quinolone antimicrobials. Three point mutations in the QRDRs of gyrA and parC were identified in all 30 ciprofloxacin-resistant S. flexneri isolates. Plasmid-mediated bla(CMY-2), bla(CTX-M-14), bla(CTX-M-15) and bla(CTX-M-55)-like genes were found in 29 ESBL-producing isolates and three clavulanic-acid-resistant isolates, and six isolates also exhibited resistance to ciprofloxacin. Distinct genetic differences in both serotypes and PFGE profiles were observed for these ciprofloxacin- or extended-spectrum-cephalosporin-resistant isolates.
  
  
  CONCLUSIONS
  ESBL-producing or fluoroquinolone-resistant Shigella is no longer an unusual phenomenon in the local community. The monitoring programme in China should stay vigilant to the dissemination of these isolates and the health agencies must take appropriate measures to restrict the abuse of antimicrobials, especially in the community.
authors.affiliation: The Children's Hospital, Urumqi, Xinjiang, China.
authors.forename: Wenli
authors.initials: W
authors.lastname: Zhang
authors.forename: Yanping
authors.initials: Y
authors.lastname: Luo
authors.forename: Jingyun
authors.initials: J
authors.lastname: Li
authors.forename: Lan
authors.initials: L
authors.lastname: Lin
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
authors.forename: Changqin
authors.initials: C
authors.lastname: Hu
authors.forename: Shaohong
authors.initials: S
authors.lastname: Jin
authors.forename: Lu
authors.initials: L
authors.lastname: Ran
authors.forename: Shenghui
authors.initials: S
authors.lastname: Cui
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D002511:Cephalosporins / Q000494:pharmacology; D002681:China; D002939:Ciprofloxacin / Q000494:pharmacology; D002969:Clavulanic Acids / Q000494:pharmacology; D027081:DNA Gyrase / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004405:Dysentery, Bacillary / Q000382:microbiology; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D022761:Gene Transfer, Horizontal; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D015363:Quinolones / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D012703:Serotyping; D012763:Shigella flexneri / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002969:Clavulanic Acids; D004269:DNA, Bacterial; D015363:Quinolones; D002939:Ciprofloxacin; C103022:beta-lactamase CMY-2; C456080:beta-lactamase CTX-M-14; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase