On the contrary, other mucin degraders such as A. muciniphila or B. thetaiotaomicron cannot utilize sialic acid as carbon source, so will be disadvantaged by the mucin glycosylation profile of IBD patients, while more adapted to utilize complex mucin glycan structures50 that require the synergistic action of several glycoside hydrolases51. This evidence concerns the gene MUC5AC and irritable bowel syndrome.