Paediatrics Lung Disease

Abstract

Introduction: Prior studies on Protracted Bacterial Bronchitis (PBB) link wet cough with bacterial infection and inflammation of the lower airways, but the role of viral infection is not well defined. We hypothesized that viral-bacterial co-infection is more common in children with wet cough and is associated with heightened airway neutrophilia. Methods: We prospectively recruited 232 children undergoing elective fl exible bronchoscopy. Participants were grouped into wet, dry or no cough groups. Broncho-alveolar lavage (BAL) and clinical data, including presence, nature and duration of cough and key demographic factors, were collected. Results: Children with wet cough were more likely to have lower airway bacterial infection (OR 2.6, p = 0.001), viral infection (OR 2.04, p = 0.045) and viral-bacterial co-infection (OR 2.65, p = 0.042) compared to those with dry or no cough. Viral-bacterial co-infection was associated with the highest median %neutrophils (33.5%) compared to bacteria only, virus/es only and no infection (20%, 18% and 6%, respectively, p < 0.0001). Conclusion: Lower airway infection (viral and/or bacterial) is more common in children with wet cough. The greatest neutrophilic airway infl ammation is seen in children with viral-bacterial co-infection of their lower airways. Support: Financial Markets Foundation for children (project), Allen & Hanburys, QCMRI and NHMRC (for DW), NHMRC (for JU and AC). Conflict of Interest: None.