title: Changes in the Distribution of Capsular Serotypes of Streptococcus pneumoniae Isolated from Adult Respiratory Specimens in Japan.
abstract: OBJECTIVE
  The objective of this study was to assess whether the distribution of pneumococcal capsular types has been changed, while also providing basic data on changes in the distribution after the introduction of Pneumococcal conjugated vaccine (PCV)13 in adult medical practice.
  
  
  METHODS
  We analyzed 431 Streptococcus pneumoniae strains (200 in 2006 and 231 in 2012) that had been isolated from respiratory infection specimens from adult patients. Capsular typing was performed by the Quellung reaction and multiplex polymerase chain reaction.
  
  
  RESULTS
  A comparison of the 2006 and 2012 strains revealed that the number and proportion of strains by serotype increased from 30 (15%) to 46 (20%) for serotype 3, from 4 (2%) to 14 (6%) for serotype 6A, and from 4 (2%) to 13 (6%) for serotype 6C, whereas the number and proportion of strains by serotype decreased from 8 (4%) to 0 (0%) for serotype 4 and from 24 (12%) to 17 (7%) for serotype 6B. From 2006 to 2012, the coverage rate significantly decreased from 39 to 28.1% for PCV7 (p=0.017).
  
  
  CONCLUSIONS
  Our study showed a decrease in the vaccine coverage of PCV7. However, PCV13 covered serotypes 3 and 6A, which are prevalent, as well as penicillin-resistant S. pneumoniae strains. At present, PCV13 in adult clinical practice seems to be highly significant. However, there is a possibility that the distribution has changed, and careful screening should be continued in the future.
authors.affiliation: Division of Clinical Infectious Diseases, Department of Medicine, School of Medicine, Showa University, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Shoji
authors.forename: Masayuki
authors.initials: M
authors.lastname: Maeda
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Shirakura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Takuma
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hanaki
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Niki
mesh_terms: D000368:Aged; D002353:Carrier State / Q000276:immunology*; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000008:administration & dosage*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000276:immunology* / Q000517:prevention & control; D015995:Prevalence; D012141:Respiratory Tract Infections / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine