Clostridioides difficile-Associated Antibiotics Alter Human Mucosal Barrier Functions by Microbiome-Independent Mechanisms

Abstract

A clinically relevant risk factor forClostridioides difficile-associated dis-ease (CDAD) is recent antibiotic treatment. Although broad-spectrum antibioticshave been shown to disrupt the structure of the gut microbiota, some antibioticsappear to increase CDAD risk without being highly active against intestinal anaerobes, suggesting direct nonantimicrobial effects. We examined cell biological effectsof antibiotic exposure that may be involved in bacterial pathogenesis using aninvitrogermfree human colon epithelial culture model. We found a marked loss of mucosal barrier and immune function with exposure to the CDAD-associated antibiotics clindamycin and ciprofloxacin, distinct from the results of pretreatment with anantibiotic unassociated with CDAD, tigecycline, which did not reduce innate immuneor mucosal barrier functions. Importantly, pretreatment with CDAD-associated antibi-otics sensitized mucosal barriers to C. difficiletoxin activity in primary cell-derived enteroid monolayers. These data implicate commensal-independent gut mucosal barrier changes in the increased risk of CDAD with specific antibiotics and warrantfurther studies inin vivosystems. We anticipate this work to suggest potential ave-nues of research for host-directed treatment and preventive therapies for CDAD.