Probiotic Supplement for Recurrent UTIs in Healthy Women (L. Plantarum, L. Rhamnosus, B. Lactis)

This randomized, double-blind, placebo-controlled trial will evaluate the efficacy of a probiotic food supplement containing Lactiplantibacillus plantarum PBS067, Lacticaseibacillus rhamnosus LRH020, and Bifidobacterium animalis subsp. lactis BL050 in women with recurrent uncomplicated urinary tract infections (UTIs). Seventy healthy non-menopausal women aged 18 to 50 years with a history of recurrent uncomplicated acute cystitis will be randomized 1:1 to receive either the probiotic supplement or placebo. Participants will undergo a 28-day intensive treatment phase followed by a maintenance phase consisting of 7 treatment days per month for approximately 4 months and a 28-day treatment-free follow-up period. The primary objective is to evaluate the effect of the probiotic supplement on time to first recurrence of symptomatic uncomplicated UTI over a 24-week observation period. Secondary objectives include assessment of cumulative recurrence incidence, antibiotic use, urinary symptom severity, quality of life, fecal persistence of the probiotic strains, and changes in gut microbiota composition.

Inclusion Criteria: Female participants meeting all of the following criteria will be eligible for participation: * Aged 18 to 50 years; * Not postmenopausal; * Able to understand and sign the informed consent form; * Able to understand and comply with the study requirements; * Negative HIV test; * Negative pregnancy test; * History of at least 2 episodes of uncomplicated acute cystitis within the 6 months prior to the baseline visit (T0), confirmed by urinalysis and/or previous urine culture with antimicrobial susceptibility testing; * No signs or symptoms of acute cystitis (e.g., dysuria, increased urinary frequency, or urgency) at the baseline visit (T0); * Negative rapid urine leukocyte test at baseline; * Urinary bacterial count \38°C, flank or back pain, or chills) within 14 days prior to the baseline visit, or unresolved previous urinary tract infection; * Vulvovaginitis at screening; * HIV infection or acquired immunodeficiency; * Severe visual or hearing impairment that may interfere with study participation; * Known allergy or hypersensitivity to any ingredient of the investigational product or placebo; * Alcohol, recreational drug, nicotine, caffeine, or theine abuse; * Use of antibacterial products that, in the investigator's opinion, may interfere with the study results; * Use of concomitant treatments, including food supplements, probiotics, or herbal products, administered systemically or topically, that may interfere with the study objectives, except for treatments prescribed by the investigator for the management of an acute UTI during the study; * Any past or concomitant medical condition, including diabetes, kidney disease, Crohn's disease, ulcerative colitis, or other conditions that, in the investigator's opinion may interfere with the study results.