Increased Risk of Pneumonia and Bronchiolitis after Bacterial Colonization of the Airways as Neonates

摘要

Rationale: The frequency of pneumonia and bronchiolitis exhibits considerable variation in otherwise healthy children, and suspected risk factors explain only a minor proportion of the variation. We hypothesized that alterations in the airway microbiome in early life may be associated with susceptibility to pneumonia and bronchiolitis in young children. Objectives: To investigate the relation between neonatal airway colonization and pneumonia and bronchiolitis during the first 3 years of life. Methods: Participants comprised children of the Copenhagen Prospective Studies on Asthma in Childhood_(2000) (COPSAC_(2000)) cohort, a prospective birth cohort study of 411 children born to mothers with asthma. Aspirates from the hypopharynx at age 4 weeks were cultured for Streptococcus pneumoniae, Haemophilus influenzae, Morax-ella catarrhalis, and Staphylococcus aureus. Clinical information on pneumonia and bronchiolitis within the first 3 years of life was pro-spectively collected by the research physicians at the center. Analyses were adjusted for covariates associated with pneumonia and bronchiolitis and bacterial airway colonization. Measurements and Main Results: Hypopharyngeal aspirates and full clinical follow-up until 3 years of age were available for 265 children. Of these, 56 (21%) neonates were colonized with 5. pneumoniae, H. influenzae, and/or M. catarrhalis at 4 weeks of age. Colonization with at least one of these microorganisms (but not 5. aureus) was significantly associated with increased incidence of pneumonia and bronchiolitis (adjusted incidence rate ratio, 1.79 [1.29-2.48]; P ＜ 0.005) independently of concurrent or later asthma. Conclusions: Neonatal airway colonization with 5. pneumoniae, H. influenzae, or M. catarrhalis is associated with increased risk of pneumonia and bronchiolitis in early life independently of asthma. This suggests a role of pathogenic bacterial colonization of the airways in neonates for subsequent susceptibly to pneumonia and bronchiolitis.