2568. Mechanisms of a Specific Probiotic Comprised of Lactobacillus acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2 that Interferes with Clostridioides difficile 20291 Toxin Production
Bibliographic record
Abstract
Abstract Background Clostridioides difficile infections (CDI) result from antibiotic use and cause severe diarrhea (C. difficile-associated diarrhea, CDAD) which is life-threatening and costly. A specific probiotic containing Lactobacillus acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2 (Bio-K+) has demonstrated benefits in preventing CDI and has a strong inhibitory effect on the growth of several nosocomial C. difficile strains in vitro. Many Lactobacilli can inhibit CD growth though lactic acidification. Here, we have investigated novel acid-independent mechanisms by which these strains impair C. difficile virulence. Methods The hypervirulent strain C. difficile R20291 was co-cultured anaerobically with Bio-K+ probiotic strains in various media and glucose concentrations (5 g/L, 3 g/L, 0 g/L), for 24 hours at 37°C. Parameters such as Log CFU, pH, Toxin A and B, cell cytotoxicity were measured. Statistical comparisons using ANOVA one-way was performed in order to determine whether the groups were significantly different. Results At 5 g/L glucose, no C. difficile toxin was produced and co-culture with these lactobacilli resulted in potent acidification and growth inhibition. At 3 g/L glucose, C. difficile toxin production occurred and acidification by the lactobacilli resulted in growth inhibition as well as >99% reduced Toxin A and B production. In the absence of glucose and a starting pH of 7.0, TY broth, the lactobacilli did not acidify the medium and C. difficile growth was normal yet Toxin A and B production was partially reduced at, 20% and 41% lower. Toxin B from the supernatant of C. difficile grown in TY was cytotoxic to human fibroblast cells, but this was less cytotoxic when co-cultured with the Lactobacilli. Conclusion These results suggest that the combination of L. acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2 interferes with C. difficile pathogenesis through: 1) inhibition of C. difficile growth (via lactic acid secretion), 2) reduced toxin A/B synthesis and (3) toxin neutralization. These results might explain the strain specificity of Bio-K+ probiotic bacteria in potentially preventing C. difficile-associated diarrhea in antibiotic treated patients. Disclosures All authors: No reported disclosures.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".