title: Serotypes, antibiotic susceptibilities, and multi-locus sequence type profiles of Streptococcus agalactiae isolates circulating in Beijing, China.
abstract: BACKGROUND
  To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections.
  
  
  METHODS
  All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles.
  
  
  RESULTS
  In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB.
  
  
  CONCLUSIONS
  S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB.
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China; Department of Obstetrics, Beijing Obstetrics and Genecology Hospital, Capital Medical University, Beijing, 100026, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China.
authors.forename: Jing-jing
authors.initials: JJ
authors.lastname: Tong
authors.affiliation: Department of Obstetrics, People's Hospital of Beijing Daxing District, Capital Medical University, Beijing, 102600, China.
authors.forename: Xiu-hua
authors.initials: XH
authors.lastname: Ma
authors.affiliation: Department of Obstetrics, People's Hospital of Beijing Daxing District, Capital Medical University, Beijing, 102600, China.
authors.forename: Feng-li
authors.initials: FL
authors.lastname: Song
authors.affiliation: Department of Obstetrics, Beijing Obstetrics and Genecology Hospital, Capital Medical University, Beijing, 100026, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Fan
authors.affiliation: Department of Obstetrics, Beijing Obstetrics and Genecology Hospital, Capital Medical University, Beijing, 100026, China.
authors.forename: Cui-mei
authors.initials: CM
authors.lastname: Guo
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China.
authors.forename: Sang-jie
authors.initials: SJ
authors.lastname: Yu
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China.
authors.forename: Kai-hu
authors.initials: KH
authors.lastname: Yao
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China.
authors.forename: Yong-hong
authors.initials: YH
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D002681:China; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology; D065288:Serogroup; D013292:Streptococcus agalactiae / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004917:Erythromycin