Efficacy and Safety of Lactobacillus acidophilus LA85 in Preventing Antibiotic-Associated Diarrhea: A Randomized, Placebo-Controlled Study.

2025-06
Food science & nutrition 13(6)

PubMed: 40548185
DOI: 10.1002/fsn3.70490

Study Design

Type: Randomized Controlled Trial (RCT)
Sample size: n = 82
Population: 82 adult participants receiving amoxicillin treatment
Methods: randomized, double-blind, placebo-controlled trial; participants were randomized to receive either LA85 (2 × 10^9 CFU/day) or placebo for 14 days

Antibiotic-associated diarrhea (AAD) is a common clinical complication resulting from antibiotic-induced gut microbiota dysbiosis. Lactobacillus acidophilus LA85, a probiotic strain illustrated with in vitro antimicrobial and immunomodulatory properties, may offer a preventive approach against AAD. However, clinical evidence on its efficacy remains limited. This randomized, double-blind, placebo-controlled trial evaluated the efficacy and safety of L. acidophilus LA85 in preventing amoxicillin-associated diarrhea. A total of 82 adult participants receiving amoxicillin treatment were randomized to receive either LA85 (2 × 10⁹ CFU/day) or placebo for 14 days. The primary outcomes included AAD incidence, diarrhea duration, and stool consistency, while secondary outcomes assessed gastrointestinal quality of life and safety. LA85 supplementation was associated with a trend toward a reduction in the incidence of AAD; however, this difference did not reach statistical significance. Nonetheless, LA85 notably shortened the duration of diarrhea episodes compared to placebo (p = 0.072), suggesting a clinically meaningful improvement. Participants receiving LA85 exhibited less variability in stool consistency scores, assessed by the Bristol stool form scale (BSFS), maintaining scores consistently around 3.5. In contrast, placebo recipients had greater fluctuations between 3.5 and 4.0, indicating less stable stool consistency during antibiotic treatment. Importantly, exploratory subgroup analysis revealed that in younger participants (< 53 years age), LA85 supplementation significantly reduced the incidence of AAD (p = 0.008) and effectively eliminated persistent diarrhea episodes. Gastrointestinal quality of life scores improved significantly in the probiotic group (p < 0.05). No serious adverse events were reported, supporting the safety of LA85. While these findings support the clinical application of LA85 for preventing AAD, further large-scale trials incorporating microbiome analysis and longer follow-up periods are necessary to confirm its long-term benefits and generalizability. Trial Registration: This clinical trial (ClinicalTrials.gov Identifier: NCT05974657) was registered on August 3, 2023.

Research Insights

Supplement	Dose	Health Outcome	Effect Type	Effect Size	Source
Lactobacillus acidophilus LA85	—	Improved Quality of Life	Beneficial	Small	View source Gastrointestinal quality of life scores improved significantly in the probiotic group (p < 0.05).
Lactobacillus acidophilus LA85	—	Improved Stool Consistency	Beneficial	Small	View source Participants receiving LA85 exhibited less variability in stool consistency scores, assessed by the Bristol stool form scale (BSFS), maintaining scores consistently around 3.5.
Lactobacillus acidophilus LA85	—	Reduced Antibiotic-Associated Diarrhea	Beneficial	Small	View source LA85 supplementation was associated with a trend toward a reduction in the incidence of AAD; however, this difference did not reach statistical significance.
Lactobacillus acidophilus LA85	—	Reduced Duration of Diarrhea	Beneficial	Small	View source LA85 notably shortened the duration of diarrhea episodes compared to placebo (p = 0.072), suggesting a clinically meaningful improvement.
Lactobacillus acidophilus LA85	—	Reduced Incidence of Antibiotic-Associated Diarrhea	Beneficial	Moderate	View source In younger participants (< 53 years age), LA85 supplementation significantly reduced the incidence of AAD (p = 0.008) and effectively eliminated persistent diarrhea episodes.