title: Pneumococcal serogroups and serotypes in severe pneumococcal pneumonia in Belgian children: theoretical coverage of the 7-valent and 9-valent pneumococcal conjugate vaccines.
abstract: BACKGROUND
  Although the causative pneumococcal serotypes of invasive diseases are already extensively studied, few data are available about the pneumococcal serotypes additionally isolated from broncho-alveolar lavage samples in childhood pneumonia.
  
  
  OBJECTIVE
  To identify the causative pneumococcal serotypes in culture proven childhood community acquired pneumonia (CAP) and to calculate the effectiveness of the heptavalent and nonavalent pneumococcal vaccine (7- and 9-valent PnV) in severe pneumococcal pneumonia.
  
  
  METHODS
  All pneumococcal isolates stored from broncho-alveolar lavage, blood culture and pleural fluid in healthy children with CAP were characterized.
  
  
  RESULTS
  Seventy children (median age 2 years 3.5 months) could be included. The most prevalent serotypes were: SGT1 (21.4%), SGT6 (20.0%), SGT19 (12.8%), SGT23 (10.0%), and SGT14 (7.1%). SGT1 was especially prevalent in complicated cases and children >5 years. This first ranking of SGT1 is not reported in invasive pneumococcal disease studies. The overall theoretical coverage of the 7-valent PnV and the 9-valent PnV for pneumococcal pneumonia was 45.7% and 72.8%. The theoretical coverage of both vaccines was equal for non-invasive pneumonia (64%) but the theoretical coverage of the 9-valent PnV for invasive pneumonia was much higher (79% vs. 37.2%). Antibiotic susceptibility to penicillin was 84%, 70% to tetracycline and 61% to erythromycin; however only one strain (MIC = 4 mg/L) was highly resistant to penicillin.
  
  
  CONCLUSIONS
  Based on this serotyping, the theoretical coverage of the 7-valent PnV for proven pneumococcal pneumonia is good but decreases with age. A 9-valent PnV containing SGT1 could significantly increase the coverage, especially for invasive pneumonia. According to these data, penicillin remains the first choice antibiotic treatment for childhood CAP in Belgium.
authors.affiliation: Department of Pediatrics, Pediatric Respiratory Medicine, Cystic Fibrosis Clinic and Infectiology, Brussels, Belgium.
authors.forename: Iris
authors.initials: I
authors.lastname: De Schutter
authors.forename: Anne
authors.initials: A
authors.lastname: Malfroot
authors.forename: Denis
authors.initials: D
authors.lastname: Piérard
authors.forename: Sabine
authors.initials: S
authors.lastname: Lauwers
mesh_terms: D000293:Adolescent; D001530:Belgium; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000627:therapeutic use*; D008826:Microbial Sensitivity Tests; D022242:Pneumococcal Vaccines / Q000627:therapeutic use*; D011018:Pneumonia, Pneumococcal / Q000517:prevention & control*; D012703:Serotyping; D018074:Vaccines, Conjugate / Q000627:therapeutic use*
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate