supports the survival of in a cystic fibrosis lung polymicrobial community through metabolic cross-feeding.

Cystic fibrosis (CF) is a multi-organ genetic disorder that affects more than 100,000 individuals worldwide. Chronic respiratory infections are among the hallmark complications associated with CF lung disease, and these infections are often due to polymicrobial communities that colonize the airways of persons with CF (pwCF). Such infections are a significant cause of morbidity and mortality, with studies indicating that pwCF who are co-infected with more than one organism experience more frequent pulmonary exacerbations, leading to a faster decline in lung function. Previous work established an CF-relevant polymicrobial community model composed of , , , and . cannot survive in monoculture in this model. In this study, we leverage this model to investigate the interactions between and , allowing us to understand the mechanisms by which the two microbes interact to support the growth of specifically in the context of the polymicrobial community. We demonstrate a cross-feeding mechanism whereby metabolizes mucin into short-chain fatty acids that are in turn utilized by and converted into metabolites (succinate, acetate) that are cross-fed to , supporting the survival of this anaerobe in the CF lung-relevant model.