AuthorisedTherapeutic confirmatory (Phase III)Interventional

Preventing urinary tract infections in infants and young children with probiotic E. coli Nissle: FinNissle randomized controlled trial

Urinary tract infections (UTIs) and kidney infections can be painful and distressing for young children, and they often keep coming back. Doctors usually treat them with antibiotics, but repeated courses can cause side effects and lead to antibiotic resistance. This trial is testing an oral probiotic liquid called Mutaflor to see if it can prevent future UTIs. Mutaflor contains a harmless, friendly strain of bacteria known as E. coli Nissle that may help protect the urinary system from harmful germs. Children in the study will be given either the probiotic liquid or an inactive dummy liquid (a placebo) made of sweet water. Doctors will track each child's health for six months to see whether the probiotic reduces repeat infections, cuts down the need for antibiotics, and lowers hospital visits. Taking part is completely voluntary.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Pohjois-Pohjanmaan hyvinvointialue

Enrolment target

250

Start

10 Jul 2026

Urinary tract infection or Pyelonephritis

What is this study about?

Urinary tract infections happen when unwanted bacteria get into the bladder or kidneys. In babies and young children, these infections can cause high temperatures, tummy pain, and sickness. When an infection reaches the kidneys, it is called pyelonephritis. Many children who get one UTI go on to have more, which often means taking repeated courses of antibiotics or even spending time in hospital.

Researchers want to find gentle, effective ways to stop these infections from coming back. This study tests a medicine called Mutaflor. Although it is made from E. coli bacteria, this is a special, friendly type called E. coli Nissle 1917. Unlike the germs that cause illness, these helpful bacteria are thought to strengthen the body's natural defences and crowd out harmful bugs before they can cause an infection.

This is a randomised controlled trial. Half of the children will receive the Mutaflor probiotic liquid, and the other half will receive a dummy liquid made of sugar and water (known as a placebo). A computer chooses who gets which liquid by chance, and neither parents nor doctors will know which one the child is taking until the study ends. This ensures the results are completely fair and unbiased.

Over six months, the study team will closely monitor the children. They will check how many children get another UTI, how many days of antibiotics are needed, and whether any hospital stays are prevented. If the treatment works, it could offer families a simple way to protect young children from painful urinary infections without overusing antibiotics.

Key takeaways

Tests a probiotic liquid (Mutaflor) to prevent repeat UTIs in babies and young children.
Compares the probiotic against a harmless sugar-water placebo over six months.
Aims to reduce the need for antibiotics and hospital admissions.
Children will still receive prompt standard care if an infection occurs.
Taking part is completely voluntary, and you can leave the study at any time.

Who may be eligible?

This study is designed for infants and young children who are at risk of having repeat urinary tract infections or kidney infections. Both boys and girls can take part.

Children typically join the study after finishing treatment for a recent UTI. Because this trial involves young children, doctors will carefully check your child's medical background to ensure that taking a probiotic liquid is safe and suitable for them.

Children who have certain rare health conditions, severely weakened immune systems, or known allergies to any ingredients in the liquid may not be able to take part. The study doctor will go through all health details with you before you make any decisions.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

My child is an infant or young child.
My child has recently had a diagnosed UTI or kidney infection.
I am able to give an oral liquid medicine to my child at home.
I am willing to track my child's symptoms and attend check-ups for six months.

Answer every question to see your result.

What does participation involve?

If you decide to enrol your child, they will take a small amount of liquid medicine by mouth. Half of the children will receive the probiotic liquid, and half will receive a sweet sugar-water placebo. You will be asked to keep a simple record of your child's health over six months. In this diary, you will note down any tummy aches, loose stools, or signs of a new infection, as well as any medicines your child takes. The study team will check in regularly through clinic appointments or phone calls. If your child develops signs of an infection, they will be tested and treated straight away. The total follow-up period is six months.

Potential risks and benefits

The main hope is that the probiotic will help prevent your child from getting another UTI, which could mean fewer antibiotics and fewer hospital visits. However, because this is a trial, there is no guarantee of direct benefit, and your child might receive the placebo liquid. The probiotic is widely used and generally safe, but mild side effects can happen, such as temporary wind, soft stools, or mild tummy pain. Your child will be monitored carefully throughout. Joining the trial is entirely your choice, and you can withdraw your child at any time without it affecting the care they receive from the NHS.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Finland

Common questions

Is E. coli in this medicine safe for my child?

Yes. While some types of E. coli cause illness, E. coli Nissle is a well-studied, friendly strain used safely as a probiotic to support the body's natural defences.

What happens if my child gets a UTI during the trial?

Your child will receive normal medical care right away. The study team or your GP will prescribe antibiotics if an infection is confirmed.

What is the placebo liquid made of?

The placebo is simply purified water mixed with a small amount of sugar syrup. It looks and tastes similar to the study medicine but contains no active bacteria.

How long will my child need to be in the study?

The study follows your child's health for a total of six months from the day they start.

Will taking part cost anything?

No. All study medicines, clinic visits, and tests related to the trial are provided free of charge.