Bacteria detection during rhinovirus infection is associated with asthma exacerbations

Published Online: April 3, 2014

Pathogenic bacteria detection within the upper airway during infancy has been linked to subsequent development of asthma and acute wheezing episodes in early childhood. In addition, numerous studies have demonstrated that viral illness causes asthma exacerbations in children. However, these studies have not examined the combined influence of both bacteria and rhinovirus on exacerbations of asthma.  

In an original research paper recently published in The Journal of Allergy and Clinical Immunology (JACI), Kloepfer and colleagues aimed to examine the relationship between rhinovirus, bacteria and asthma exacerbations by prospectively following over 300 school-aged children during peak fall rhinovirus season. All nasal samples were analyzed for detection of rhinovirus, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Results were linked with reported cold and asthma symptoms as well as rescue medication utilization and daily peak flows to determine when subjects experienced an asthma exacerbation.

Rhinovirus (RV) detection increased the risk of detecting bacteria, with greater quantities of bacteria being observed when RV was present. In addition, when analyzing data on a weekly basis, when RV and S. pneumoniae were detected together, subjects had the highest frequencies of exacerbations, and this combination was more likely to be associated with asthma exacerbation when compared to RV infection alone. However, some subjects experienced illness symptoms for greater than one week, so an illness-based analysis was performed and demonstrated that illnesses associated with RV and S. pneumoniae, M. catarrhalis or H. influenzae were associated with an increased risk of moderate asthma exacerbations compared to illnesses without pathogen detection.  

These findings suggest that RV infection increases the likelihood of detecting bacteria within the upper airway, and when detected along with pathogenic bacteria, this combination increases the risk of symptomatic illnesses and moderate asthma exacerbations. This association may help explain why RV infections are associated with such a broad range of clinical illness severity. If these findings are confirmed, understanding the mechanisms of RV/bacterial interactions could lead to new therapeutic approaches to respiratory illnesses and asthma.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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