What they have discovered is that in the presence of antibiotics, the bacteria are able to change from a highly regular walled form to a completely random, cell wall-deficient form called the L-form state. As such, the bacteria can easily hide from our immune system as well as antibiotics.
In L-form the bacteria are weaker but some survive, hiding inside the body. They can then re-form their cell wall and the patient will be faced with recurring UTIs.
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