Detection of Pathogenic Bacteria During Rhinovirus Infection is Associated with Increased Respiratory Symptoms and Exacerbations of Asthma

Abstract

Background Detection of either viral or bacterial pathogens is associated with wheezing in children, however the influence of both bacteria and virus on illness symptoms has not been described. Objective We evaluated bacterial detection during peak RV season in children with and without asthma to determine if an association exists between bacterial infection and the severity of RV illnesses. Methods 308 children (166 with asthma, 142 without asthma) ages 4–12 years provided five consecutive weekly nasal samples during September, and scored cold and asthma symptoms daily. Viral diagnostics and quantitative PCR for Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were performed on all nasal samples. Results Detection rates were 53%, 17% and 11% for H. influenzae, S. pneumoniae and M. catarrhalis, respectively, with detection of RV increasing the risk of detecting bacteria within the same sample (OR 2.0, 95% CI 1.4–2.7, p<0.0001) or the following week (OR 1.6 (1.1–2.4), p=0.02). In the absence of RV, S. pneumoniae was associated with increased cold symptoms (mean 2.7 (95% CI 2.0–3.5) vs. 1.8 (1.5–2.2), p=0.006) and moderate asthma exacerbations (18% (12%–27%) vs. 9.2% (6.7%–12%), p=0.006). In the presence of RV, S. pneumoniae was associated with increased moderate asthma exacerbations (22% (16%–29%) vs. 15% (11%–20%), p=0.01). Furthermore, M. catarrhalis detected alongside RV increased the likelihood of experiencing cold and/or asthma symptoms compared to isolated detection of RV (OR 2.0 (1.0–4.1), p=0.04). Regardless of RV status, H. influenzae was not associated with respiratory symptoms. Conclusion RV infection enhances detection of specific bacterial pathogens in children with and without asthma. Furthermore, these findings suggest that M. catarrhalis and S. pneumoniae contribute to the severity of respiratory illnesses, including exacerbations of asthma.