title: Serotype distribution, antimicrobial resistance, and molecular characterization of invasive group B Streptococcus isolates recovered from Chinese neonates.
abstract: BACKGROUND
  Group B Streptococcus (GBS) is an important neonatal pathogen associated with high morbidity and mortality in developed countries. However, data describing neonatal GBS disease in developing countries, particularly in Asia, are largely incomplete. The aim of this study was to determine the serotype distribution, antimicrobial resistance, and molecular characteristics of invasive GBS isolates recovered from Chinese neonates.
  
  
  METHODS
  From 2008 to 2013, 40 GBS isolates were recovered from infected neonates less than 3 months of age. All isolates were identified with the CAMP test and commercially available techniques. Serotyping was performed by latex agglutination. Antibiotic susceptibility was tested with Etest strips and the disk diffusion method. Multilocus sequence typing and erythromycin resistance gene detection (ermB and mefA) were performed by PCR.
  
  
  RESULTS
  Four serotypes were identified. Serotype III (85%) was the most prevalent, followed by Ia (7.5%), Ib (5%), and V (2.5%). All isolates were sensitive to penicillin, ceftriaxone, and levofloxacin. However, resistance to erythromycin (92.5%), clindamycin (87.5%), and tetracycline (100%) was observed. Among erythromycin-resistant isolates, 73.0% carried the ermB gene alone, 5.4% carried the mefA gene alone, and 21.6% expressed both ermB and mefA genes. A total of seven sequence types (STs) were identified; the most prevalent was ST17, accounting for 80% of all isolates. Further, serotype III isolates contained ST17 (94.2%), ST19 (2.9%), and ST650 (2.9%).
  
  
  CONCLUSIONS
  Serotype distribution, antimicrobial susceptibility, and sequence type characterization in Asia and in other global regions may contribute to improve the prevention and treatment of neonatal GBS infections.
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics (Capital Medical University), Ministry of Education, Beijing Pediatrics Research Institute, Beijing Children's Hospital Affiliated to Capital Medical University, Nan Lishi Road, Beijing 100045, China; Department of Pediatrics, Beijing Obstetrics and Gynecology Hospital and Beijing Maternal and Child Health Care Hospital, Affiliated to Capital Medical University, Beijing, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: Laboratory of Bacteriology and Department of Respiratory Diseases, Shenzhen Children's Hospital, Shenzhen, China.
authors.forename: Zhuoya
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics (Capital Medical University), Ministry of Education, Beijing Pediatrics Research Institute, Beijing Children's Hospital Affiliated to Capital Medical University, Nan Lishi Road, Beijing 100045, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Tong
authors.affiliation: Laboratory of Bacteriology and Department of Respiratory Diseases, Shenzhen Children's Hospital, Shenzhen, China.
authors.forename: Ruizhen
authors.initials: R
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics (Capital Medical University), Ministry of Education, Beijing Pediatrics Research Institute, Beijing Children's Hospital Affiliated to Capital Medical University, Nan Lishi Road, 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 (Capital Medical University), Ministry of Education, Beijing Pediatrics Research Institute, Beijing Children's Hospital Affiliated to Capital Medical University, Nan Lishi Road, Beijing 100045, China.
authors.forename: Sangjie
authors.initials: S
authors.lastname: Yu
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics (Capital Medical University), Ministry of Education, Beijing Pediatrics Research Institute, Beijing Children's Hospital Affiliated to Capital Medical University, Nan Lishi Road, Beijing 100045, China.
authors.forename: Kaihu
authors.initials: K
authors.lastname: Yao
authors.affiliation: Laboratory of Bacteriology and Department of Respiratory Diseases, Shenzhen Children's Hospital, Shenzhen, China.
authors.forename: Yuejie
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics (Capital Medical University), Ministry of Education, Beijing Pediatrics Research Institute, Beijing Children's Hospital Affiliated to Capital Medical University, Nan Lishi Road, Beijing 100045, China. Electronic address: yyh628628@sina.com.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004917:Erythromycin / Q000494:pharmacology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D058885:Multilocus Sequence Typing; D065288:Serogroup; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D004917:Erythromycin
keywords: Group B Streptococcus isolates; Microbial drug resistance; Newborn infant; Serotype distribution