title: Genetically diverse serotypes III and VI substitute major clonal disseminated serotypes Ib and V as prevalent serotypes of Streptococcus agalactiae from 2007 to 2012.
abstract: BACKGROUND
  Streptococcus agalactiae [group B Streptococcus (GBS)] has become more prevalent in nonpregnant women, the elderly, and people who are immunocompromised. We investigated the serotype and genomic changes of GBS human isolates from different hospitals from 2007 to 2012.
  
  
  METHODS
  The serotype and genotype of 658 GBS human isolates were determined with multiplex polymerase chain reaction and pulsed field gel electrophoresis analysis. Multilocus sequence typing analysis determined the sequence type (ST) of the major clones of serotypes Ib, V, and VI.
  
  
  RESULTS
  Most of the isolates were collected from urine samples (60.5%) with a reduction in the rate from 74.6% in 2007 to 34.5% in 2012 and from infected patients older than 30 years (72.6%). The female/male ratio differed depending on the source: 3.52 in the urine group, 0.48 in the wound group, and 0.43 in pus. Serotypes Ib (16.5%), III (16.9%), V (27.2%), and VI (17.6%) were the most predominant among the nine serotypes identified and were separated into two prevalence patterns: a decrease in serotypes Ib and V and an increase in serotypes III and VI from 2007 to 2012. The prevalence change was associated with the urine group. Additionally, serotype VI become more prevalent in blood samples in four hospitals. The pulsed field gel electrophoresis analysis demonstrated three genetic patterns: limited pulsotypes and a major clonal dissemination for serotypes Ib and V, diverse pulsotypes for serotypes III, and diverse pulsotypes with a major clonal dissemination for serotype VI. Multilocus sequence typing analysis of the major clones identified ST12 for serotype Ib and ST1 for serotypes V and VI.
  
  
  CONCLUSIONS
  Rapid genomic variations with different evolutionary patterns have led to the establishment of serotypes III and VI as the predominant GBS serotypes.
authors: Department of Pediatrics, Chang Gung Memorial Hospital, Chiayi, Taiwan, ROC.
authors: Ying-Hsiang
authors: YH
authors: Wang
authors: Department of Microbiology, Immunology, and Biopharmaceuticals, National Chiayi University, Chiayi, Taiwan, ROC.
authors: Chih-Cheng
authors: CC
authors: Lu
authors: Graduate Institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Taoyuan, Taiwan, ROC; Division of Pediatric Infectious Diseases, Chang Gung Children's Hospital, Taoyuan, Taiwan, ROC.
authors: Cherng-Hsun
authors: CH
authors: Chiu
authors: Department of Pediatrics, Chang Gung Memorial Hospital, Chiayi, Taiwan, ROC.
authors: Mei-Hei
authors: MH
authors: Wang
authors: Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan, ROC.
authors: Tsung-Han
authors: TH
authors: Yang
authors: Department of Microbiology, Immunology, and Biopharmaceuticals, National Chiayi University, Chiayi, Taiwan, ROC. Electronic address: cschu@mail.ncyu.edu.tw.
authors: Chishih
authors: C
authors: Chu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D060885:Multiplex Polymerase Chain Reaction; D065288:Serogroup; D012703:Serotyping; D013290:Streptococcal Infections / Q000188:drug therapy* / Q000453:epidemiology*; D013292:Streptococcus agalactiae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents
keywords: Fluoroquilonone resistance; Group B Streptococcus serotype; Multilocus sequence typing; Pulsotypes