title: High prevalence of Streptococcus pneumoniae with mutations in pbp1a, pbp2x, and pbp2b genes of penicillin-binding proteins in the nasopharynx in children in Japan.
abstract: OBJECTIVE
  To evaluate the resistances of Streptococcus pneumoniae to beta-lactams developed by stepwise alterations in high-molecular-weight penicillin-binding proteins (PBPs) with a reduced binding affinity of beta-lactams. Among the numerous mutations in pbp genes that alter the affinity for beta-lactams, the decreased affinity of PBP1A, 2X and 2B is especially important in the development of resistances to beta-lactams.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  In this study, we investigated the mutations in pbp1a, pbp2x, and pbp2b genes evaluated by polymerase chain reaction (PCR) in 866 pneumococcal isolates collected from the nasopharynx of Japanese children with acute otitis media.
  
  
  RESULTS
  210 strains (24.3%) exhibited no mutations in the three pbp genes. 333 strains (38.5%) had mutations in the three pbp genes, 78 (9.0%) in two pbp genes, whereas 245 (28.3%) displayed mutations in only one pbp gene. Among the 656 strains with mutations in pbp genes, 620 (94.5%) strains had mutations in pbp2x. The annual prevalence of antimicrobial-resistant S. pneumoniae showed a gradual increase in strains with mutations in the three pbp genes and a parallel decrease in strains without mutations.
  
  
  CONCLUSIONS
  PCR-based genotyping can characterize the antimicrobial resistances in pneumococci along with minimal inhibitory concentrations (MICs). Physicians should pay attention to the recent increase in antimicrobial-resistant S. pneumoniae when treating pediatric acute otitis media.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan.
authors.forename: Muneki
authors.initials: M
authors.lastname: Hotomi
authors.forename: Dewan S
authors.initials: DS
authors.lastname: Billal
authors.forename: Jun
authors.initials: J
authors.lastname: Shimada
authors.forename: Masaki
authors.initials: M
authors.lastname: Suzumoto
authors.forename: Kazuma
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Keiji
authors.initials: K
authors.lastname: Fujihara
authors.forename: Noboru
authors.initials: N
authors.lastname: Yamanaka
mesh_terms: D000208:Acute Disease; D001426:Bacterial Proteins / Q000235:genetics*; D002648:Child; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009305:Nasopharynx / Q000382:microbiology*; D010033:Otitis Media / Q000382:microbiology*; D046915:Penicillin-Binding Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012189:Retrospective Studies; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D046915:Penicillin-Binding Proteins