A single intravesical instillation of <i>Lactobacillus rhamnosus</i> GG is safe in children and adults with neuropathic bladder: A phase Ia clinical trial

<b>Context/objective:</b> Manipulation of the microbiome is an emerging approach to promote health. We conducted a Phase Ia safety study of a single bladder instillation of probiotics in asymptomatic patients with neuropathic bladder to determine the tolerability and safety of a single <i>Lactobacillus</i> instillation. <b>Design:</b> Phase Ia safety study. <b>Setting:</b> Outpatient rehabilitation clinic at a rehabilitation hospital (adults) and urology clinic at a free-standing children’s hospital (children). <b>Participants:</b> Ten patients with neuropathic bladder were included: five children with spina bifida and five adults with spinal cord injury. <b>Interventions:</b> A single <i>Lactobacillus rhamnosus</i> GG (Culturelle, 20 billion live organisms) instillation. <b>Outcome measures:</b> After the instillation, participants self-monitored symptoms using the Urinary Symptoms Questionnaire for People with Neuropathic Bladder using Intermittent Catheterization daily for one week. Repeat urinalysis, urine culture, and 16S bacterial rRNA-based microbiome analyses were performed 7–10 days after instillation. <b>Results:</b> Probiotic instillation was well-tolerated. One child had upper respiratory tract symptoms during the trial, and two had transient cloudy urine. No adults reported any symptoms following instillation. <i>Lactobacillus</i> did not grow on culture post-instillation. There were differences in beta diversity of the urine microbiome in children vs. adults with neuropathic bladder (P Lactobacillus was present in the pre-instillation urinary microbiomes all of the adults and 4 out of 5 of the pediatric subjects, and identified in 4 out of 5 of both the adult and pediatric subjects’ post-instillation urinary microbiomes. <b>Conclusion:</b> Intravesical instillation of Culturelle probiotic may be safe and well-tolerated in patients with neuropathic bladder.