Severe acute inflammatory responses to initial UTI lead to bladder damage and allow infection to persist, causing chronic flare-ups, according to a US study.
Writing online in the journal PLoS Pathogens the researchers said the findings may lead to the development of a human vaccine to help prevent recurrent infection.
The team from the Washington University School of Medicine in Missouri assessed the impact of initial UTI on bladder damage in mice.
The researchers then repeated the experiment using immunodeficient mice.
Mice that had a history of chronic bladder infection, despite treatment with antibiotics to clear up the infection, went on to be affected by persistent immune cell infiltrations of bacteria within the bladder wall.
Researchers found these mice were also susceptible to further UTI.
In addition, mice that lacked the typical acute inflammatory responses were protected from chronic bladder infection.
Lead author Dr Thomas Hannan wrote: 'We found markers in the mice that may one day help us identify patients vulnerable to recurrent infection and refine our treatment strategies.
'There were infection-fighting elements in the responses of some mice that we might, for example, be able to promote through vaccines for these patients.'
Although the millions of people affected by UTI each year can be treated with antibiotics, resistance is an increasing concern. Women and children are among the most at risk of recurrent UTI.
The researchers said that they will now collaborate with researchers at the University of Washington and Duke University to see if the mouse results can lead them to markers of vulnerability to recurrent infection in humans.