Neonates colonized with pathogenic bacteria in the airways have a low-grade systemic inflammation

BACKGROUND AND OBJECTIVES: The development of childhood asthma is associated with neonatal colonization with pathogenic bacteria in hypopharynx. Furthermore, established asthma is associated with systemic low-grade inflammation. We here report on the association between neonatal colonization with pathogenic bacteria in hypopharynx and the development of systemic low-grade inflammation.

METHODS: Bacterial colonization of the hypopharynx with M. catharralis, H. influenzae and/or S. pneumoniae was assessed in asymptomatic children from the Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000 ) cohort at age 1 month by culturing technique (N=238) and by quantitative polymerase chain reaction (qPCR) technique (N=249) and in the COPSAC2010 cohort by culturing at age 1 month (N=622) and again at age 3 months (N=613). Systemic low-grade inflammation was determined in both cohorts at age 6 months by measuring plasma levels of high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α) and interleukine-6 (lL-6).

RESULTS: In both cohorts, bacterial colonization was associated with increased levels of hs-CRP: COPSAC2000 , 1 month culturing (geometric mean ratio of colonized/non-colonized [95% CI]), 1.39 [0.97-2.01], p=0.08, 1 month qPCR, 1.55 [1.14-2.10], p<0.01; COPSAC2010 , 1 month, 1.52 [1.23-1.87], p<0.01, and 3 month, 1.57 [1.30-1.90], p<0.01. A multi-parametric principal component analysis incorporating hs-CRP, TNF-α and IL-6 confirmed a systemic inflammatory profile in children colonized with M. catharralis, H. influenzae and/or S. pneumoniae in the hypopharynx compared to non-colonized children (p-values<0.05).

CONCLUSION: The composition of the upper airway microbiome in early life may cause systemic low-grade inflammation. This article is protected by copyright. All rights reserved.