Dynamics of nasopharyngeal pneumococcal carriage during the course of viral bronchiolitis

The effect of viral infection on nasopharyngeal carriage of Streptococcus pneumoniae during childhood is not well known. We studied dynamics of pneumococcal colonization by quantitative PCR during the natural course of viral bronchiolitis. At time of admission, 47 (47%) of 100 patients with bronchiolitis carried pneumococci. In patients with viral bronchiolitis who did not receive antibiotics, pneumococcal load decreased from time of admission to discharge (n = 35, cycle threshold 23 vs. 25, P = 0.0017) and from discharge to follow-up (n = 22, cycle threshold 25 vs. 40, P = 0.003). We conclude that viral respiratory infection is negatively associated with pneumococcal colonization of the upper airways. Pediatr Pulmonol. 2016;51:863–867.