Prevotella in the airway: implications for lung health and pathogen defense mediated by Prevotella-host interactions

Prevotella species are an extremely common and abundant bacteria detected within the low microbial biomass of the lungs and are a core component of the oral microbiome. Clinical studies have drawn associations between Prevotella abundance and lung homeostasis, indicating potential relationships between Prevotella and lung inflammation, infection defense, and lung function. Across several studies in critically ill patients, the depletion of Prevotella and other obligate anaerobes is linked to significantly reduced survival, leading to calls for anaerobe preservation in empiric antibiotic therapy regimens. In recent years, mechanistic studies have provided new information regarding Prevotella-host relationships, highlighting several processes by which Prevotella exposure activates epithelial, innate, and adaptive immune responses. Prevotella species also have direct and indirect effects on important lung bacterial pathogens, including Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa, with Prevotella species-dependent consequences for pathogen infection and regulation of pathogen-induced inflammation. This review summarizes our current understanding regarding how Prevotella regulate lung immune homeostasis, with a discussion of key knowledge gaps necessary for the translation of these insights into new therapeutic approaches to reduce the burden of lung infection and disease.