Of note, Mucispirillum and Desulfovibrio are among the colitogenic gut microbiomes, being used as microbial markers in active colitis owing to their opportunistic nature given the putative capacity of Mucispirillum to degrade mucin (Robertson et al., 2005; Berry et al., 2012) and Desulfovibrio to produce high levels of hydrogen sulfide during active inflammation (Carbonero et al., 2012), which may further fuel inflammation. Here, MUC5AC is linked to colitis.