title: Outbreak of scarlet fever associated with emm12 type group A Streptococcus in 2011 in Shanghai, China.
abstract: BACKGROUND
  An unprecedented, large outbreak of childhood scarlet fever occurred in Shanghai between April and July 2011. Investigation of the epidemiology could enhance our understanding of the factors related to the outbreak.
  
  
  METHODS
  We retrospectively analyzed the demographic and seasonal characteristics of children with scarlet fever and the outcome. During the peak month of the 2011 outbreak, 45 GAS isolates recovered from pediatric patients and 13 (43.3%) GAS isolates recovered from 30 asymptomatic student contacts were characterized by emm typing, superantigen profiles, pulsed-field gel electrophoresis genotypes, mutilocus sequence typing and antimicrobial susceptibility.
  
  
  RESULTS
  The 2011 outbreak of scarlet fever started in April and peaked in May and June. Boys outnumbered girls (65.1% versus 34.9%). Preschool and primary school children accounted for 96% of cases. No severe outcome was found. emm1, emm12 and emm75 were identified among 58 GAS isolates, and 53 (91.4%) isolates belonged to emm12, st36. Ten pulsed-field gel electrophoresis genotypes were identified among emm12 GAS isolates, 43 (81.1%) shared SPYS16.001 genotype and the remaining 7 genotypes detected were related to SPYS16.001 closely or possibly. No streptococcal pyrogenic exotoxin A and streptococcal pyrogenic exotoxin M were detected in 58 isolates. All emm12 GAS isolates were resistant to azithromycin and clindamycin.
  
  
  CONCLUSIONS
  emm12 GAS strain caused the large 2011 outbreak of scarlet fever in Shanghai. Antibiotic resistance to macrolides and clindamycin in GAS is prevalent in Shanghai.
authors.affiliation: Department of Infectious Diseases, Children’s Hospital of Fudan University, 399 Wanyuan Road, Shanghai 201102, China. zengmeigao@yahoo.com.cn
authors.forename: Mingliang
authors.initials: M
authors.lastname: Chen
authors.forename: Weilei
authors.initials: W
authors.lastname: Yao
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Yuefang
authors.initials: Y
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Gangyi
authors.initials: G
authors.lastname: Wang
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.forename: Hao
authors.initials: H
authors.lastname: Pan
authors.forename: Jiayu
authors.initials: J
authors.lastname: Hu
authors.forename: Mei
authors.initials: M
authors.lastname: Zeng
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D000942:Antigens, Bacterial / Q000145:classification / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000145:classification / Q000235:genetics*; D002352:Carrier Proteins / Q000145:classification / Q000235:genetics*; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D012541:Scarlet Fever / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein