To test the impact of the addition of Bacteroides to the CF gut microbiome, we designed a mouse experiment wherein the native gut microbiome of specific pathogen-free CftrF508del mice [also called Cftrem1Cwr (34), which carry the most common CFTR allele] was first suppressed by sustained antibiotic treatment, and then, the microbiota was replaced by oral gavage with a stool pool from children with CF. Here, CFTR is linked to cystic fibrosis.