Approximately, 3% of males and 8% of females will develop a urinary tract infection (UTI) during childhood, and most of these will be effectively treated by short-term antibiotic therapy. A subset of these children (20-48%), will develop recurrent UTI (RUTI), which may have long-term effects in the form of hypertension or renal damage.

In an effort to prevent RUTIs physicians prescribe sulfamethoxazole-trimethoprim (Septra) or nitrofurantoin as low dose antibiotic prophylaxis. However, recent evidence suggests that during prophylactic therapy the body is exposed to antibiotic levels capable of increasing antibiotic resistance and bacterial virulence. This has been shown to be true in the uropathogens E. coli and Staphylococcus saprophyticus, yet it is not known if Enterococcus sp. demonstrate similar mechanisms. Additionally, antibiotics have been shown to disrupt the natural balance of the human microbiome, potentially leading to major long term problems.

As a uropathogen, enterococci consistently rank in the top 3 causes of RUTI, especially in children under 3 years of age. Additionally, Enterococcus is notorious for developing antibiotic resistance and studies have shown that children with enterococcal UTIs exhibit a higher rate of recurrence than those with non-enterococcal UTIs.

The investigators hypothesize the current practice of antibiotic prophylaxis in children with RUTI is detrimental and can change the bacterial and sensitivity profiles of these patients.

Patients meeting the inclusion criteria will be recruited to the study at Dr. Dave's discretion through the urology clinic. As clinically indicated patients will then fall into one of two groups, patients receiving antibiotic prophylaxis or those undergoing clinical observation. This reflects the standard of care these children receive and no additional procedures are mandated.

At the initial appointment information sheets and consent forms will be given to the parent/caregiver to consider; due to the nature of the study, the parent or legal guardian will be required to give informed consent. Following the receipt of informed consent, patients will be asked to provide a mid stream urine sample given they are infection free and not currently on antibiotics. Patients will be assessed simultaneously for dysfunctional elimination syndrome (DES) through review of their 48-hour bowel bladder diary, the completed Dysfunctional Voiding Scoring System (DVSS) questionnaire and performing uroflowmetry. Patients may withdraw from the study at any stage without repercussion.

Patients in the antibiotic prophylaxis group will receive a 3-month script for antibiotic prophylaxis, if clinically indicated according to the standard of care. Septra (Trimethoprim dose 2 mg/kg) or nitrofurantoin (dose 2 mg/kg) will be the antibiotics used for prophylaxis based on past cultures or allergy history. Antibiotic prescription will be renewed at 3 months and an informal assessment on compliance will be performed through review of the number of doses left. Patients not tolerating one of these antibiotics will be offered the alternate. From months 6-12, prophylaxis will cease (washout period) unless a symptomatic UTI is suspected at which point appropriate treatment will be implemented. Lifestyle changes, behavioural modification and management of constipation will be instituted in both groups. Patients will return for follow up visits at 3, 6, 9 and 12 months. In addition, patients can return to the urology clinic at any time if UTI is suspected.

Urine samples will be collected at baseline and at 3, 6, 9 and 12 months from both groups (prophylaxis versus observation) by registered nurses at Children's Hospital, London Health Sciences Centre. Healthy patients, those with no recent history of UTI or antibiotic use or known urinary tract abnormalities, will be included to give an indication of the healthy urinary microbiota in the paediatric population. These participants will be asked to provide urine at two time points a minimum of three months apart. Samples will be assessed for bacterial identification via both culture dependent and independent methods. Antibiotic susceptibility profiles will be determined for viable organisms using the Kirby Bauer disk method and bacterial virulence analyzed via bladder and kidney cell line adherence and internalization assays, as well as PCR to determine the presence of virulence genes associated with the pathogen (adhesins, fimbriae, toxins). Urinary cytokine analysis via Luminex will also be conducted as a measure of host bladder state, immune response and disease severity.

Inclusion Criteria:

• Patient has experienced a minimum of 2 UTIs within the last year, as well as a culture proven UTI for inclusion into either of the RUTI groups.
• Patients must be deemed to require antibiotic prophylaxis, at the discretion of Dr. Dave and following the standard of care, for inclusion in the antibiotic prophylaxis group.
• Patients with no known urological abnormalities, recent history of UTI or antibiotic use are eligible for inclusion in the healthy patient group.

Exclusion Criteria:

• Patients with an abnormal urinary tract as determined through the use of ultrasound and, given an abnormal ultrasound, or greater than two febrile UTIs, a voiding cystourethrogram (VCUG). The use of both ultrasound and VCUG given these indications is standard of care.

1 year - Over the course of prophylaxis or clinical observation.

Adverse events were reported according to the clinicaltrials.gov definitions.

Adverse event information was collected during clinical appointments.