Lactobacillus rhamnosus PL1 and Lactobacillus plantarum PM1 versus placebo as a prophylaxis for recurrence urinary tract infections in children: a study protocol for a randomised controlled trial.

BACKGROUND Urinary tract infections (UTIs) are one of the most common bacterial infections in children. In children < 7 years of age, the prevalence of one episode of symptomatic UTI has been estimated at 3-7% in girls and 1-2% in boys, whereas 8-30% of them will have one or more episodes of UTI. The use of some probiotics appears to reduce the risk of recurrence of UTIs. Since the effects of probiotics are strain-specific, the efficacy and safety of each strain has to be assessed. The main aim of this study is to determine whether probiotics (containing Lactobacillus rhamnosus PL1 and Lactobacillus plantarum PM1) therapy are effective in preventing UTI in children compared to placebo. METHOD A superiority, double-blind, randomised, controlled trial is being conducted. One hundred and six patients aged 3 to 18 years with recurrent UTIs in last year (defined as: ≥ 2 episodes of UTI with acute pyelonephritis/upper UTI; or 1 episode of UTI with acute pyelonephritis and ≥ 1 episodes of UTI with cystitis/lower UTI; or ≥ 3 episodes of UTI with cystitis/lower UTI) or children with ≥ 1 infection in the upper urinary tract and ≥ 1 of recurrent UTIs risk factors (congenital anomalies of the kidney and urinary tract, constipation, bladder dysfunction, myelomeningocele, sexual activity in girls) will be randomly assigned to receive a 90-day prophylaxis arm (probiotic containing L. rhamnosus PL1 and L. plantarum PM1) or a 90-day placebo arm. The primary outcome measure will be the frequency of recurrence of UTI during the intervention and in the period 9 months after the intervention. DISCUSSION The findings of this randomised controlled trial (RCT), whether positive or negative, will contribute to the formulation of further recommendations on prevention of recurrent UTIs in children. TRIAL REGISTRATION NUMBER NCT03462160, date of trial registration 12th March 2018.