The Role of the Gut Microbiome in Urinary Tract Infections and Recurrent Cystitis

Abstract

Objective: To investigate the association between gut microbiome composition and recurrent UTI, evaluate changes in gut microbial diversity following treatment, and assess the effectiveness of probiotic supplementation as an adjunct to standard antibiotic therapy.

Study Design: Pre-test/post-test quasi-experimental study.
Place and Duration of Study: This study was conducted at the Outpatient Urology Clinics of Mansoura University Hospital, Egypt, from January 2023 to June 2024 for a period of 18 months.

Methods: A pre-test/post-test quasi-experimental study was conducted involving 60 patients with recurrent UTIs and 60 healthy controls recruited from outpatient urology clinics.

Results: At baseline, patients with recurrent UTIs exhibited significantly lower gut microbial alpha diversity than healthy controls (Shannon index: 2.84 ± 0.43 vs. 3.91 ± 0.38; p < 0.001). Intestinal colonization with Escherichia coli was significantly more frequent in patients with recurrent UTIs than in controls (68.3% vs. 18.3%, p < 0.001). After 12 weeks, patients receiving probiotic supplementation demonstrated significantly greater restoration of gut microbial diversity compared with those receiving antibiotics alone (Shannon index: 3.62 ± 0.41 vs. 2.91 ± 0.39; p < 0.001).

Conclusion: Gut microbiome dysbiosis is strongly associated with susceptibility to recurrent UTIs. Adjunctive
probiotic therapy targeting restoration of the gut–bladder axis significantly improves gut microbial diversity and reduces UTI recurrence.