While the physiological effect of these changes on the host is difficult to assess from genomic data alone, it is worth noting that both of these Proteobacterial genera have potential associations with disease: Bilophila has been associated with the production of sulfide, which leads to degradation of host mucin and induces colitis in mouse models32,33, while Sutterella has been associated with insulin resistance in obese patients, and autism with gastrointestinal disturbance in children34,35. This evidence concerns the gene MUC5AC and colitis.