title: Microbiology of bronchoalveolar lavage fluid in children with acute nonresponding or recurrent community-acquired pneumonia: identification of nontypeable Haemophilus influenzae as a major pathogen.
abstract: BACKGROUND
  Precise etiologic diagnosis in pediatric community-acquired pneumonia (CAP) remains challenging.
  
  
  METHODS
  We conducted a retrospective study of CAP etiology in 2 groups of pediatric patients who underwent flexible bronchoscopy (FOB) with bronchoalveolar lavage (BAL); children with acute nonresponsive CAP (NR-CAP; n = 127) or recurrent CAP (Rec-CAP; n = 123). Procedural measures were taken to limit contamination risk and quantitative bacterial culture of BAL fluid (significance cutoff point, ≥ 10⁴ colony-forming units/mL) was used. Blood culture results, serological test results, nasopharyngeal secretion findings, and pleural fluid culture results were also assessed, where available.
  
  
  RESULTS
  An infectious agent was detected in 76.0% of cases. In 51.2% of infections, aerobic bacteria were isolated, of which 75.0%, 28.9%, and 13.3% were Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae, respectively. Most (97.9%) of the H. influenzae strains were nontypeable (NTHi). H. influenzae was detected in 26.0% of NR-CAP cases and 51.2% of Rec-CAP cases, whereas Mycoplasma pneumoniae was the predominant pathogen in the NR-CAP group (accounting for 34.9% of cases) but not in the Rec-CAP group (19.3%). Viruses were found in 30.4% of cases, with respiratory syncytial virus, parainfluenzaviruses, and influenzaviruses detected most frequently. Mixed infections were found in 18.9% of NR-CAP cases and 30.1% of Rec-CAP cases.
  
  
  CONCLUSIONS
  A variety of microorganisms were isolated with frequent mixed infection. NTHi was one of the major pathogens found, especially in association with recurrent CAP, possibly because of improved detection with the FOB with BAL procedure. This suggests that the burden of pediatric CAP could be reduced by addressing NTHi as a major causative pathogen.
authors.affiliation: Department of Pediatric Pulmonology, CF-Clinic and Pediatric Infectious Diseases, niversitair Ziekenhuis Brussel (UZ Brussel), Brussels. iris.deschutter@uzbrussel.be
authors.forename: Iris
authors.initials: I
authors.lastname: De Schutter
authors.forename: Elke
authors.initials: E
authors.lastname: De Wachter
authors.forename: Françoise
authors.initials: F
authors.lastname: Crokaert
authors.forename: Jan
authors.initials: J
authors.lastname: Verhaegen
authors.forename: Oriane
authors.initials: O
authors.lastname: Soetens
authors.forename: Denis
authors.initials: D
authors.lastname: Piérard
authors.forename: Anne
authors.initials: A
authors.lastname: Malfroot
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification*; D001769:Blood / Q000382:microbiology; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D010996:Pleural Effusion / Q000382:microbiology; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D015995:Prevalence; D012008:Recurrence; D012189:Retrospective Studies
chemical_list: D000907:Antibodies, Bacterial