Recurrent cystitis is a common condition in menopausal women and is associated with impaired quality of life and increased antibiotic use. This randomized, double-blind, placebo-controlled clinical trial aims to evaluate the efficacy and safety of Colipral® in preventing recurrent cystitis in menopausal women. Participants will be randomized to receive either Colipral® (probiotic strain Escherichia coli 5C (ECP24®)))or placebo for 12 weeks and will be followed for a total of 24 weeks. The study will assess the occurrence of symptomatic cystitis recurrences confirmed by urine culture, as well as symptoms, quality of life, urinary pain, and antibiotic consumption.

Recurrent cystitis, defined as two or more episodes within 6 months or three or more episodes within 12 months, is particularly frequent in menopausal women because of age-related changes in estrogen levels, the urogenital epithelium, and the microbiota. The gastrointestinal tract is considered an important reservoir of uropathogenic bacteria, and intestinal dysbiosis may contribute to recurrent urinary tract infections.

This study is a randomized, double-blind, placebo-controlled, parallel-group clinical trial designed to evaluate whether Colipral® (probiotic strain Escherichia coli 5C (ECP24®)) reduces the proportion of menopausal women experiencing recurrent symptomatic cystitis compared with placebo during a 24-week follow-up period. Recurrence is defined as the appearance of urinary symptoms compatible with the need for therapy and confirmed by urine culture.

A total of 134 menopausal women with recurrent cystitis will be enrolled and randomized in a 1:1 ratio to receive either Colipral® or placebo. Participants in the active treatment group will receive one capsule daily for 12 weeks, while participants in the control group will receive an identical placebo for the same duration. The follow-up period will continue beyond treatment discontinuation to evaluate the persistence of the preventive effect.

Secondary objectives include evaluation of the number of cystitis episodes, time to first recurrence, antibiotic consumption, urinary pain assessed by the Visual Analogue Scale (VAS), symptom severity, and quality of life assessed using the UTI-SIQ-8 questionnaire.

Inclusion Criteria:

• Menopausal female patients.
• Age between 55 and 70 years.
• Diagnosis of recurrent cystitis: ≥2 episodes in 6 months or ≥3 episodes in 12 months, with at least 1 documented episode from urine culture in the last 12 months (if available).

Exclusion Criteria:

• Complicated urinary tract infections (UTIs) or major complicating factors, including relevant anatomical abnormalities, catheterization, active calculosis, or significant immunosuppression.
• Hormone replacement therapy (HRT) that has been ongoing or discontinued for less than 6 months.
• Pyelonephritis within the past 6 months.
• Ongoing continuous antibiotic prophylactic therapy (or inability to suspend it).
• Chronic inflammatory bowel diseases (ulcerative colitis or Crohn's disease).
• Allergy to the probiotic or its excipients.

The study will be conducted in a double-blind manner. Participants, care providers, investigators, and outcome assessors will remain blinded to treatment allocation. Active treatment and placebo will be indistinguishable in appearance and packaging. Unblinding will only be permitted in emergency situations.