title: An eight-year study of Shigella species in Beijing, China: serodiversity, virulence genes, and antimicrobial resistance.
abstract: BACKGROUND
  This study was conducted to determine the prevalence of serotypes, virulence factors, and antimicrobial resistance patterns of Shigella spp. in Beijing, China, from 2004 to 2011.
  
  
  METHODS
  Real-time PCR assays were used to detect virulent genes, and the Kirby-Bauer disk diffusion method was used to evaluate antimicrobial resistance.
  
  
  RESULTS
  Among the total of 1,652 Shigella isolates, S. sonnei (57.1%) was the predominant species, followed by S. flexneri (42.3%), S. dysenteriae (0.4%), and S. boydii (0.2%). Nineteen serotypes were discovered among S. flexneri strains. The virulence gene ipaH was the most frequent, followed by sen and set. The presence of set showed significant difference in two dominant serogroups, S. flexneri and S. sonnei. Over 90% of Shigella isolates showed resistance to at least three drugs with widened spectrum. High-level antimicrobial resistance to single and multiple antibiotics was more common among S. sonnei than S. flexneri.
  
  
  CONCLUSIONS
  There was an obvious serotype change and a dramatic increase of antibiotic resistance in Shigella prevalence in Beijing.
authors.affiliation: Beijing Centre for Disease Prevention and Control, Beijing, China. meiqu@126.com.
authors.forename: Mei
authors.initials: M
authors.lastname: Qu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Guirong
authors.initials: G
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: Lei
authors.initials: L
authors.lastname: Jia
authors.forename: Weili
authors.initials: W
authors.lastname: Liang
authors.forename: Xitai
authors.initials: X
authors.lastname: Li
authors.forename: Xiaona
authors.initials: X
authors.lastname: Wu
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Hanqiu
authors.initials: H
authors.lastname: Yan
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
authors.forename: Quanyi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002681:China; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D008137:Longitudinal Studies; D008826:Microbial Sensitivity Tests; D060888:Real-Time Polymerase Chain Reaction; D012703:Serotyping; D012760:Shigella / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D012764:Shigella sonnei / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D014774:Virulence / Q000187:drug effects
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C063500:ipaH protein, Shigella flexneri