Why do some women get bladder infections all the time?
This post is for all you ladies who have had this really annoying recurrent infection: urinary tract infections or UTIs. It will also be centering around this paper, which came out last year and gave some interesting clues as to why UTIs are recurrent for some women.
There is one bacterium in particular, Escherichia coli, which is the main cause of UTIs. When scientists study UTIs, they sometimes use mice as a model organism to do so. This means that they experimentally infect mice with E. coli, in order to understand better how the bacteria behaves and to improve treatment for people in the future. In these mice, scientists see that E. coli can set up long-lasting camps in the lining of the bladder and the tubes inside your body that lead to it (collectively known as the urinary tract).
Scientists have thought for a while that some cases of UTIs may be due to these E. coli breaking camp to wage war on your urinary tract due to some unknown call to battle. However, in the paper I linked to above, Nicole M. Gilbert and colleagues started to shed some light on what this call to battle might be.
Gilbert and her colleagues set up a new mouse model to better reflect what goes on in the average woman's urinary tract. It's important here to remember that E. coli are not the only bacteria inside you. You have a huge amount of bacteria within you, and a lot of them are good for you! These 'good' bacteria usually only cause problems when they are transferred from one body zone to another. For instance, when women first get a UTI, it's often not only E. coli that is transferred to the urinary tract. Other bacteria that normally live inside the vagina can also be transferred accidentally, simply due to the close proximity of women's urinary and reproductive tracts.
Gilbert and her colleagues built on this knowledge. They thought that perhaps it could be some of this misplaced vaginal bacteria that could trigger E. coli sitting at camp to spring to battle and cause a recurrent UTI! The authors found that indeed, some of these vaginal bacteria, for instance one called Gardnerella vaginalis, could act like an on/off switch for E. coli growth.
Cool, right? But what's the take-home message?
If you're just a pure science lover, you might take home the idea that it's pretty cool that your normal microbiota can talk to each other to cause health or disease.
If you're a more practical type, you might take home the message that we might have new treatments for UTIs come out that focus on changing the conversation between different species of bacteria like G. vaginalis and E. coli. If we can interrupt their conversation, it might be possible to interrupt the UTI.
Finally, if you get UTIs yourself, this gives you a tip: usually, in women G. vaginalis gets into the urinary tract during sexual activity - so showering after sex might help prevent recurrent infections!
That's all for this week - until next week, stay healthy!