A systematic review evaluating efficacy of probiotics in prevention and treatment of bacterial infections.

AIMS: To evaluate the efficacy of probiotics in preventing or treating bacterial infections across different infection types in recently published randomized controlled trials (RCTs). PATIENTS AND METHODS: Systematic review of 12 RCTs (2021-2026) addressing probiotics (single or multistrain) for recurrent urinary tract infections (rUTI), Helicobacter pylori eradication, respiratory tract infections (RTI), acne vulgaris, and multidrug-resistant (MDR) bacterial colonization. RoB assessed using Cochrane RoB 2.0; qualitative GRADE certainty assessment performed for all primary outcomes. Narrative synthesis with vote-counting analysis conducted due to heterogeneous study designs and outcomes. RESULTS: Across 12 RCTs (n = 1200 participants), probiotics demonstrated consistent directional benefit for rUTI (2 RCTs: 75% recurrence-free vs. 33% placebo), H. pylori eradication (3 RCTs: 70-86% eradication rates), and RTI symptom reduction (3 RCTs: 64-96% improvement). Acne lesion reduction was observed in two RCTs. MDR colonization results were inconsistent (two RCTs). GRADE certainty of evidence ranged from low to moderate across all outcomes, primarily due to imprecision from small sample size and heterogenicity. CONCLUSIONS: Probiotics show promise as adjuvant therapy for select bacterial infections, but evidence certainty is low. Larger structured RCTs with standardized outcome measures are required before routine clinical recommendations can be established. PROTOCOL REGISTRATION: PROSPERO; https://www.crd.york.ac.uk/PROSPERO identifier is CRD420261339142.