Probiotic Driven Competitive Exclusion in the Human Gut: A Meta Analysis of Microbial Diversity and Pathogen Suppression

Background: The human microbiome, particularly the gut microbiota, is essential for health maintenance and disease prevention. Probiotics, defined as live microorganisms that provide health benefits to the host, are increasingly recognized for their capacity to inhibit pathogenic bacteria through competitive exclusion. This meta‑analysis systematically evaluates the effectiveness of probiotics in reducing pathogen colonization within the human gut. Methods: A comprehensive literature search was conducted across PubMed and Scopus from October 2018 to August 2023, identifying in vivo studies reporting competitive exclusion by probiotics. Thirty studies met the qualitative criteria, with four contributing quantitative data. Results: The pooled odds ratio for the impact of probiotics on pathogen exclusion was 1.68 [1.13–2.51], demonstrating a statistically significant benefit (p < 0.01). Heterogeneity was minimal (I² = 0%), supporting the robustness of the findings. Conclusions: Results underscored the efficacy of Lacticaseibacillus, Limosilactobacillus, and Bifidobacterium strains in competitive exclusion. These findings support the integration of probiotics into therapeutic strategies for managing gastrointestinal infections and highlight the need for future research on strain‑specific effects and optimal dosing.