Lead researchers

About the project 

The most common bacterial infections for which antibiotics are used are urinary tract infections (UTIs). These occur most commonly in women, with more than half having at least one UTI in their life, and many having recurrent infections. This means that UTIs in women play a big part in the development of bacteria that are resistant to antibiotics.

Having recurrent UTIs has a major impact on women’s quality of life. Those who have had recurrent UTIs (3 or more UTIs in the last 12 months or 2 or more in the last 6 months) are usually given antibiotics in one of three ways: (i) to start as soon as they have symptoms, (ii) as a low dose to take every day, or (iii) to take after sex. Currently, low dose daily antibiotics (option (ii) above) are the only proven way of preventing infections, so if the quality of life of these women is to be improved and antibiotic use reduced, different ways of preventing UTIs must be found.

Probiotics contain large numbers of friendly bacteria and can be used to boost friendly bacteria (called Lactobacilli) that live in women’s vaginas. Certain types of vaginal Lactobacilli  (for example,  L. reuteri/ L. rhamnosus) may prevent urine infections, stopping the bacteria attaching to the bladder and multiplying. Our study will use probiotics by mouth, which are strongly preferred by the patients who are helping us design this study. They are safe to use, side effects are uncommon and, if present, usually mild, such as abdominal discomfort.

We are also interested in antibiotic use, how satisfied women are with probiotic treatment, if they have any side effects, and the costs to the NHS and patients.

Project aim

To investigate the clinical and cost-effectiveness of prophylactic probiotics compared to placebo for reducing clinically suspected urinary tract infections (i.e. resulting in NHS contact) in women with recurrent urinary tract infection.

Anticipated impacts

New evidence regarding a potentially useful intervention to prevent urinary infections and thereby reduce antibiotic use.


Funding application submitted to National Institute for Health Research (NIHR) Health Technology Assessment Programme

Project dates 

To be confirmed