title: High prevalence of beta-lactam-resistant Haemophilus influenzae type b isolates derived from respiratory tract specimens in Japanese patients.
abstract: OBJECTIVE
  Serotypeable strains of Haemophilus influenzae, which can cause invasive infections, are found in the respiratory tract at low frequencies. We compared the antibiotic resistance of the typeable and nontypeable strains of H. influenzae in respiratory tract specimens obtained in Japan.
  
  
  METHODS
  We determined the serotypes and the antibiotic susceptibilities of 440 clinical H. influenzae strains isolated from respiratory tract specimens. We also examined the prevalence of genotypes that are associated with beta-lactam resistance.
  
  
  RESULTS
  The majority of the strains were nontypeable (421 strains, 95.7%). The remainder belonged to serotypes b (10 strains, 2.3%), e (three strains, 0.7%), or f (six strains, 1.4%). The type b strains exhibited the expression of beta-lactamase and resistance mutations in penicillin-binding protein 3 with significantly higher frequencies than other strains.
  
  
  CONCLUSIONS
  H. influenzae type b strains, which are associated with meningitis and bacteremia, derived from respiratory tract specimens, shared more beta-lactam-resistant mechanisms than nontypeable and other serotype strains.
authors.affiliation: Department of Microbiology, Sapporo Medical University School of Medicine, South-1, West-17, Chuo-ku, Sapporo 060-8556, Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Yokota
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohkoshi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Sato
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Fujii
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000382:microbiology; D019741:Haemophilus influenzae type b / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009154:Mutation; D046915:Penicillin-Binding Proteins / Q000235:genetics; D015995:Prevalence; D012137:Respiratory System / Q000382:microbiology*; D012703:Serotyping; D055815:Young Adult; D018440:beta-Lactam Resistance; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D046915:Penicillin-Binding Proteins; D047090:beta-Lactams