Respiratory Viral Infection-Induced Microbiome Alterations and Secondary Bacterial Pneumonia

Abstract

Influenza and other respiratory viral infections are the most common type of acute respiratory infection. Viral infections predispose patients to secondary bacterial infections, which often have a more severe clinical course. The mechanisms underlying post-viral bacterial infections are complex, and include multifactorial processes mediated by interactions between viruses, bacteria, and the host immune system. Studies over the past 15 years have demonstrated that unique microbial communities reside on the mucosal surfaces of the gastrointestinal tract and the respiratory tract, which have both direct and indirect effects on host defense against viral infections. In addition, antiviral immune responses induced by acute respiratory infections such as influenza are associated with changes in microbial composition and function (“dysbiosis”) in the respiratory and gastrointestinal tract, which in turn may alter subsequent immune function against secondary bacterial infection or alter the dynamics of inter-microbial interactions, thereby enhancing the proliferation of potentially pathogenic bacterial species. In this review, we summarize the literature on the interactions between host microbial communities and host defense, and how influenza, and other acute respiratory viral infections disrupt these interactions, thereby contributing to the pathogenesis of secondary bacterial infections.

Genomic Diversity of Severe Acute Respiratory Syndrome–Coronavirus 2 in Patients With Coronavirus Disease 2019

“…Aside from the pathogen, microbiota in the lung is associated with disease susceptibility and severity [7]. Alterations of lung microbiota could potentially modify immune response against the viral and secondary bacterial infection [8,9]. Thus, understanding the microbiota, which comprises bacteria that could cause secondary infection or exert effects on the mucosal immune system, might help to predict the outcome and reduce complications.…”

Association between multiple respiratory viral infections and pediatric intensive care unit admission among infants with bronchiolitis

“…Therefore, the results of multiplex PCR must be interpreted together with the patients' clinical presentation. However, there is also evidence suggesting that subclinical viral infection leads to alteration of the host-microbe composition of the respiratory tract, which might be linked to subsequent dysregulation in host immune function associated with development of asthma or against bacterial infection [23,24]. The impact of altered microbiota in the respiratory tract after viral infections awaits future studies.…”

Respiratory viral infection alters the gut microbiota by inducing inappetence

“…However, several studies have demonstrated that respiratory infections are associated with a change in the composition of the gut microbiota (Wang et al, 2014;Deriu et al, 2016;Bartley et al, 2017;Groves et al, 2018;Hanada et al, 2018;Yildiz et al, 2018). We have previously observed that viral lung infections alter the gut microbiota, leading to an increase in the relative abundance of Bacteroidetes and a decrease in the relative abundance of Firmicutes (Groves et al, 2018).…”