title: Increased prevalence of penicillin-resistant viridans group streptococci in Japanese children with upper respiratory infection treated by beta-lactam agents and in those with oncohematologic diseases.
abstract: BACKGROUND
  Viridans group streptococci, especially penicillin-resistant strains, have been emerging as pathogens of bacteremia in neutropenic patients with hematologic malignancies.
  
  
  OBJECTIVE
  To survey the penicillin susceptibilities of viridans group streptococci in Japanese children with and without oncohematologic diseases and to evaluate the effect of the short term administration of beta-lactam agents on the antibiotic susceptibility.
  
  
  METHODS
  We tested 113 isolates of viridans group streptococci by the microdilution method for the minimal inhibitory concentrations (MICs) to 10 antibiotics. We isolated 40 isolates from the throats of children with an upper respiratory infection (URI) before beta-lactam antibiotic treatment, 32 isolates after the treatment, 33 isolates in hospitalized children with oncohematologic diseases and 8 isolates from blood.
  
  
  RESULTS
  Twenty-five isolates (62.5%) from the children with URI before treatment were penicillin-intermediate or -high level resistant (MIC > or = 0.25 microg/ml). The prevalence of those isolates after antibiotic treatment (87.5%) was significantly increased compared with that before treatment (P = 0.03). The prevalences of the penicillin-high level resistant isolates (MIC > or = 4 microg/ml) in the children with oncohematologic diseases (39.4%) and in the isolates from blood (62.5%) were significantly higher than that in the children with URI before treatment (12.5%) (P < 0.01). Decreased susceptibilities to other beta-lactam agents were observed in the penicillin-high level resistant strains.
  
  
  CONCLUSIONS
  The high prevalence of penicillin-intermediate or -high level resistant viridans group streptococci in healthy Japanese children was documented. The administration of beta-lactam agents decreased the prevalence of penicillin-susceptible isolates in the children with URI. High prevalences of penicillin-high level resistant isolates were observed in the oncohematologic patients and in the isolates from blood.
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Kagoshima University, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mogi
authors.forename: J I
authors.initials: JI
authors.lastname: Nishi
authors.forename: M
authors.initials: M
authors.lastname: Yoshinaga
authors.forename: H
authors.initials: H
authors.lastname: Harada
authors.forename: S
authors.initials: S
authors.lastname: Narahara
authors.forename: K
authors.initials: K
authors.lastname: Kawakami
authors.forename: I
authors.initials: I
authors.lastname: Maruyama
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D019337:Hematologic Neoplasms / Q000150:complications*; D006801:Humans; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D012141:Respiratory Tract Infections / Q000188:drug therapy*; D013290:Streptococcal Infections / Q000188:drug therapy*; D013291:Streptococcus / Q000187:drug effects; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams