Introduction:
Clostridioides difficile (CD) is a major healthcare-associated pathogen responsible for antibiotic-associated diarrhea and severe colitis. Probiotics have been proposed as a preventive strategy. However, data in critically ill patients remain limited.

Aim:
To evaluate the effect of probiotic supplementation on CD stool concentration in patients hospitalized in coma.

Material and methods:
This prospective, randomized preliminary study was conducted from May to August 2023 at the Department of Medical Rehabilitation “Budzik dla Dorosłych”. Fourteen patients in coma were randomized to receive either a new probiotic mixture (Labifid®, containing Bifidobacterium animalis AMT30 and Bifidobacterium breve AMT32) or standard hospital probiotics (Lactobacillus rhamnosus, Saccharomyces boulardii). Stool samples were collected at baseline, 1, 2, and 4 months afterwards.

Results and discussion:
Baseline CD levels were comparable between groups (2.1 × 10⁵ vs. 2.2 × 10⁶ CFU/g; p = 0.607). At 1, 2, and 4 months, patients receiving the new probiotics demonstrated significantly lower CD concentrations than controls (p = 0.032, p = 0.017, and p = 0.029, respectively). After 4 months, CD levels in the new-probiotic group fell below the detection limit. No serious adverse events were observed.

Conclusions:
Supplementation with Bifidobacterium animalis and Bifidobacterium breve was associated with a significant reduction in CD stool concentration in comatose patients. However, due to the small sample size, it should be interpreted with caution.