HIF1A and clostridium difficile infection: Fachi et al., demonstrated in a mouse model that butyrate increases the expression of claudin in a HIF-1α-dependent manner, leading to improved barrier integrity and reduced inflammation by inhibiting microbial translocation (Fachi et al., 2019; Muenchau et al., 2019), and HIF-1α was found to be required for butyrate protection of the intestinal epithelium in a mouse model of Clostridium difficile infection (CDI) (Fachi et al., 2019).