A urinary tract infection (UTI) is an infection in any part of your urinary system; your kidneys, ureters, bladder, and urethra(1). Most infections involve the lower urinary tract, which are the bladder and the urethra. Although anyone can get a UTI they are more common in females than males, with over 50% of women experiencing one in their lifetime and 25% having recurrent episodes(2,3). The symptoms they can experience include a burning sensation when urinating and feeling the urge to urinate often. More than 80% of UTIs are caused by the gram-negative bacteria Escherichia coli (E. coli)(4,5). Although a number of E. coli bacteria strains are known to live harmoniously in small numbers within the gastrointestinal tract, when the environment allows the organisms to overgrow, they can become opportunistic pathogens(6). Despite most UTI pathogens ascending from the colon, UTIs can also be the result of persistent pathogens in the vagina. In order to cause infection, the harmful bacteria must adhere to the lining of the bladder, kidney or urethra opening and multiply(6).
How can we prevent UTIs? The current treatment for UTIs is with a short course of antibiotics. For women who experience recurring UTIs, antibiotics are prescribed on a long-term basis to reduce the risk of an infection returning. Although antibiotics are seen to be effective at treating UTIs there is a risk of antibiotic resistance(7). Several trials have looked into the use of Lactobacillus species to prevent or treat UTIs. A recent Canadian trial found two strains of Lactobacillus to be effective, as these successfully survived the harsh gastric conditions and colonise the vagina where they exert their beneficial effects. Another large clinical trial(7) involving post-menopausal women found that UTI occurrence could be reduced by 50% in women given a combination of Lactobacillus over a 12-month period. The validity of these probiotic strains was clear when in the same trial the results were compared to antibiotic treatment and seen to be equally as effective(7). These bacterial strains exist naturally in the vagina of healthy women and are known to prevent uropathogens from entering the urinary tract. Probiotics produce antibacterial agents such as hydrogen peroxide as well as acidifying the environment through lactic acid production making the urinary tract less compatible with the growth of harmful bacteria(10,11,112). Furthermore, probiotic supplementation can provide women with other benefits associated with a balanced microbiome such as improving their immune response, and strengthening gut barrier function(10).
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