A novel probiotic therapeutic in a murine model of Clostridioides difficile colitis

Clostridioides difficile infection (CDI) is a common cause of antimicrobial-associated diarrhea. Probiotics have shown variable results in decreasing its incidence and severity. We examined the efficacy of Lactobacillus reuteri administered using a novel probiotic biofilm delivery system in the treatment and prevention of CDI in a murine model. For prophylactic therapy, mice received an oral antibiotic cocktail followed by clindamycin injection, followed by probiotic administration (planktonic vs. biofilm state), followed by C. difficile oral gavage. For treatment therapy, mice received antibiotics and C. difficile first, followed by probiotic administration. Clinical sickness scores (CSS) and intestinal histologic injury scores (HIS) were assigned. In the Prophylactic Therapy model, CSS: 67% of untreated mice exposed to C. difficile demonstrated CSS ≥ 6, which is consistent with C. difficile infection (p< .001 compared to unexposed mice). In mice treated with planktonic Lr, 55% had a CSS ≥ 6, but only 19% of mice treated with Lr in its biofilm state had CSS ≥ 6 (p< .001). Mice receiving Lr + DM-Maltose lost the least amount of weight compared to mice receiving saline (p = .004676) or to mice receiving Lr (p= .003185). HIS: 77% of untreated mice exposed to C. difficile had HIS scores ≥4, which is consistent with C. difficile infection. In mice treated with planktonic Lr, 62% had HIS ≥4, but only 19% of mice treated with Lr in its biofilm state had HIS ≥4. (p< .001). Additionally, mice treated with Lr in its biofilm state had better survival compared to untreated mice and to mice treated with planktonic Lr (p ≤ 0.05). Similar findings for weight loss, CSS, HIS and survival were obtained for Treatment Therapy. A single dose of Lactobacillus reuteri in its biofilm state reduces the severity and incidence of experimental C. difficile infection when administered as both prophylactic and treatment therapy.