title: Serotype Distribution, Antimicrobial Susceptibility, and Molecular Epidemiology of Streptococcus pneumoniae Isolated from Children in Shanghai, China.
abstract: OBJECTIVE
  Streptococcus pneumoniae is a common pathogenic cause of pediatric infections. This study investigated the serotype distribution, antimicrobial susceptibility, and molecular epidemiology of pneumococci before the introduction of conjugate vaccines in Shanghai, China.
  
  
  METHODS
  A total of 284 clinical pneumococcal isolates (270, 5, 4,3, and 2 of which were isolated from sputum, bronchoalveolar lavage fluid, blood, cerebral spinal fluid, and ear secretions, respectively) from children less than 14 years of age who had not been vaccinated with a conjugate vaccine, were collected between January and December in 2013. All isolates were serotyped by multiplex polymerase chain reaction or quellung reactions and antimicrobial susceptibility testing was performed using the broth microdilution method. The molecular epidemiology of S.pneumoniae was analyzed by multilocus sequence typing (MLST).
  
  
  RESULTS
  Among the 284 pneumococcal isolates, 19F (33.5%), 19A (14.1%), 23F (12.0%), and 6A (8.8%) were the most common serotypes and the coverage rates of the 7-, 10-, and 13-valent pneumococcal conjugate vaccines (PCV7, PCV10, and PCV13) were 58.6%, 59.4% and 85.1%, respectively. Antimicrobial susceptibility showed that the prevalence rates of S.pneumoniae resistance to penicillin were 11.3% (32/284). Approximately 88.0% (250/284) of the isolates exhibited multi-drug resistance. MLST analysis revealed a high level of diversity, with 65 sequence types (STs) among 267 isolates. Specifically, the four predominant STs were ST271 (24.3%, 65/267), ST320 (11.2%, 30/267), ST81 (9.7%, 26/267), and ST3173 (5.2%, 14/267), which were mainly associated with serotypes 19F, 19A, 23F, and 6A, respectively.
  
  
  CONCLUSIONS
  The prevalent serotypes among clinical isolates from children were 19F, 19A, 23F, and 6A and these isolates showed high resistance rates to β-lactams and macrolides. The Taiwan19F-14 clone played a predominant role in the dissemination of pneumococcal isolates in Shanghai, China. Therefore, continued and regional surveillance on pneumococcal isolates may be necessary.
authors.affiliation: Department of Clinical Laboratory, Shanghai Children's Hospital, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Fen
authors.initials: F
authors.lastname: Pan
authors.affiliation: Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Lizhong
authors.initials: L
authors.lastname: Han
authors.affiliation: Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Weichun
authors.initials: W
authors.lastname: Huang
authors.affiliation: Shanghai Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Department of Clinical Laboratory, Shanghai Children's Hospital, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, Shanghai Children's Hospital, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Huihong
authors.initials: H
authors.lastname: Qin
authors.affiliation: Department of Clinical Laboratory, Shanghai Children's Hospital, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D002648:Child; D002681:China / Q000453:epidemiology; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects / Q000302:isolation & purification*
chemical_list: D000890:Anti-Infective Agents