Strain T21 Attenuates Infection in a Murine Model Through Reduction of Inflammation and Gut Dysbiosis With Decreased Toxin Lethality and Enhanced Mucin Production.

is a major cause of diarrhea in patients with antibiotic administration. T21, isolated from a human gastric biopsy, was tested in a murine infection (CDI) model and colonic epithelial cells (Caco-2 and HT-29). Daily administration of T21 [1 × 10 colony forming units (CFU)/dose] for 4 days starting at 1 day before challenge attenuated CDI as demonstrated by a reduction in mortality rate, weight loss, diarrhea, gut leakage, gut dysbiosis, intestinal pathology changes, and levels of pro-inflammatory cytokines [interleukin (IL)-1β, tumor necrosis factor (TNF)-α, macrophage inflammatory protein 2 (MIP-2), and keratinocyte chemoattractant (KC)] in the intestinal tissue and serum. Conditioned media from T21 exerted biological activities that fight against as demonstrated in colonic epithelial cells by the following: (i) suppression of gene expression and production of IL-8, an important chemokine involved in pathogenesis, (ii) reduction in the expression of (solute carrier family 11 member 1) and (human antigen R), important genes for the lethality of toxin B, (iii) augmentation of intestinal integrity, and (iv) up-regulation of , a mucosal protective gene. These results supported the therapeutic potential of T21 for CDI and the need for further study on the intervention capabilities of CDI.