title: Clonal dissemination of invasive and colonizing clonal complex 1 of serotype VI group B Streptococcus in central Taiwan.
abstract: OBJECTIVE
  The aim of this study was to investigate clinical presentation, serotype distribution and genetic correlation of group B streptococcus (GBS) diseases. Since serotype VI prevalence far exceeded that reported in prior studies, genetic relationship of isolates was further analyzed.
  
  
  METHODS
  GBS isolates obtaining from patients with invasive diseases and pregnant women with colonization between June 2007 and December 2010 were analyzed. All isolates were tested for serotypes by multiplex PCR assay and pulsed-field gel electrophoresis (PFGE). Serotype VI isolates were further analyzed by multilocus sequence typing (MLST).
  
  
  RESULTS
  A total of 134 GBS isolates were recovered from blood of 126 patients with invasive disease (94.0%) and anogenital swabs of 8 pregnant women (6.0%). Most common serotype was Ib (21.6%), followed by V (20.1%), VI (18.7%), III (15.7%), II (11.9 %), Ia (11.2%), and IX (0.7%). Serotype VI was also the leading type in infants with early onset disease (EOD; 3/8, 37.5%) and colonizing pregnant women (3/8, 37.5%). PFGE distinguished 33 pulsotypes, reflecting genetic diversity among GBS isolates. Among 25 serotype VI isolates tested, 14 were ST-1, seven were ST-679, three were ST-678, one was ST-681, and distributed into four PFGE pulsotypes. ST-678, ST-679, and ST-681 were novel sequence types; ST-678 and ST-679 are single-locus variants of ST-1 that belongs to clonal complex (CC) 1.
  
  
  CONCLUSIONS
  CC1 dissemination of serotype VI GBS thus emerges as an important invasive pathogen in infants and nonpregnant adults in central Taiwan. Serotype prevalence of GBS must be continuously monitored geographically to guide prevention strategy of GBS vaccines.
authors.affiliation: Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan; Department of Pediatrics, College of Medicine, China Medical University, Taichung, Taiwan; Department of Infectious Diseases, Children's Hospital, China Medical University Hospital, China Medical University, Taichung, Taiwan.
authors.forename: Hsiao-Chuan
authors.initials: HC
authors.lastname: Lin
authors.affiliation: Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Proteomics Core Laboratory, Department of Medical Research, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chao-Jung
authors.initials: CJ
authors.lastname: Chen
authors.affiliation: Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Kai-Hung
authors.initials: KH
authors.lastname: Chiang
authors.affiliation: Department of Infectious Diseases, Children's Hospital, China Medical University Hospital, China Medical University, Taichung, Taiwan.
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Yen
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Cheng-Mao
authors.initials: CM
authors.lastname: Ho
authors.affiliation: Department of Pediatrics, College of Medicine, China Medical University, Taichung, Taiwan; Department of Infectious Diseases, Children's Hospital, China Medical University Hospital, China Medical University, Taichung, Taiwan.
authors.forename: Kao-Pin
authors.initials: KP
authors.lastname: Hwang
authors.affiliation: Department of Pediatrics, College of Medicine, China Medical University, Taichung, Taiwan; Department of Neonatology, Children's Hospital, China Medical University Hospital, China Medical University, Taichung, Taiwan.
authors.forename: Bai-Horng
authors.initials: BH
authors.lastname: Su
authors.affiliation: Department of Neonatology, Children's Hospital, China Medical University Hospital, China Medical University, Taichung, Taiwan; School of Chinese Medicine and Department of Pediatrics, Children's Hospital, China Medical University, Taichung, Taiwan.
authors.forename: Hung-Chih
authors.initials: HC
authors.lastname: Lin
authors.affiliation: Graduate Institute of Biostatistics, College of Management, China Medical University, Taichung, Taiwan; Department of Healthcare Administration, College of Health Science, Asia University, Taichung, Taiwan.
authors.forename: Tsai-Chung
authors.initials: TC
authors.lastname: Li
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; Department of Laboratory Medicine, Linkou Chang-Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Kwei-Shan, Taoyuan, Taiwan. Electronic address: janglu45@gmail.com.
authors.forename: Jang-Jih
authors.initials: JJ
authors.lastname: Lu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000382:microbiology*; D065288:Serogroup; D013290:Streptococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D013292:Streptococcus agalactiae / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D013624:Taiwan / Q000453:epidemiology
keywords: group B Streptococcus; multilocus sequence typing (MLST); pulse-field gel electrophoresis (PFGE); sequence type