The negative results revealed: 1) A. muciniphila could allow microorganisms to enter the epithelium through mucus layer degradation (T. Zhang et al., 2021); 2) The A. muciniphila aggravated the symptoms of IBD in IL-10-deficient mice (Seregin et al., 2017), the mechanism is possible due to the lipopolysaccharides (LPS) of A. muciniphila which can cause higher levels of cytokine production including IL-1, IL-4, IL-6, TNF-α, etc. (Meng and Lowell, 1997; Singh and Jiang, 2003). Here, IL6 is linked to inflammatory bowel disease.