Bacterial colonization dynamics associated with respiratory syncytial virus during early childhood

Abstract

Respiratory syncytial virus (RSV) is an important cause of early life acute respiratory infections. Potentially pathogenic respiratory bacteria, including Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae are frequently detected during RSV infections and associated with increased illness severity. However, the temporal dynamics of bacterial colonization associated with RSV infection remain unclear. We used weekly nasal swab data from a prospective longitudinal birth cohort in Brisbane, Australia, to investigate bacterial colonization patterns within children aged less than 2 years in the 4‐week period before and after an RSV infection. During 54 RSV infection episodes recorded in 47 children, both S. pneumoniae and M. catarrhalis were detected frequently (in 33 [61.1%] and 26 [48.1%] RSV infections, respectively). In most cases, S. pneumoniae and M. catarrhalis colonization preceded the viral infection, with the nasal load of each increasing during RSV infection. Generally, the dominant serotype of S. pneumoniae remained consistent in the 1 to 2 weeks immediately before and after RSV infection. Little evidence was found to indicate that prior colonization with either bacteria predisposed participants to developing RSV infection during the annual seasonal epidemic. Possible coacquisition events, where the bacteria species was first detected with RSV and not in the preceding 4 weeks, were observed in approximately 20% of RSV/S. pneumoniae and RSV/M. catarrhalis codetections. Taken together our results indicate that RSV generally triggered an outgrowth, rather than a new acquisition, of S. pneumoniae and M. catarrhalis from the resident microbial community.

Role of Upper Respiratory Microbiota and Virome in Childhood Rhinitis and Wheeze: Collegium Internationale Allergologicum Update 2021

“…Respiratory viruses such as HRV and RSV can trigger an outgrowth, rather than a new acquisition of S. pneumoniae and M. catarrhalis from the resident microbial community [49], as well as enhance their adherence to the respiratory epithelium by upregulating the expression of bacterial adhesion molecules such as fibronectin and platelet-activating factor receptor [50], which in turn facilitate secondary bacterial infection [51], and depress innate immune responses such as neutrophil and natural killer cell recruitment [52]. HRV was also shown to induce impairment on epithelial proliferation and promote airway remodeling [53].…”

Synergism and Antagonism of Bacterial-Viral Coinfection in the Upper Respiratory Tract

“…Recent work has shown that most infants are already colonized by pneumococci at the time that they contract RSV ( 25 ). Additionally, children in low- and middle-income settings are often colonized by pneumococci early in life ( 8 ) and are therefore also likely to carry pneumococci at the time of viral infection.…”

Study Protocol for Preventing Early-Onset Pneumonia in Young Children Through Maternal Immunisation: A Multi-Centre Randomised Controlled Trial (PneuMatters)

“…Furthermore, most pneumococcal serotypes colonising the nasopharynx can cause lower airway infection ( 48 ). Even if initially a viral infection, secondary bacterial infection may ensue as bacterial densities increase further within the upper airways ( 63 ), especially in high-risk, heavily colonised. First Nations children ( 64 ) and those with a history of recurrent ALRIs.…”