Bacteria that causes common urinary tract infections could spread to the brain and cause a life-threatening abscess, scientists have warned.Klebsiella pneumoniae lives in the intestines and is normally harmless, but it can cause infections if it spreads to other areas such as the urinary tract, blood or wounds.In serious cases, it can trigger life-threatening complications including sepsis and necrotizing fasciitis, where tissue turns black and starts to die.Now, in a new case report from Germany, scientists say they have found that the bug can 'evolve' and spread to the brain.Researchers at a hospital in Cologne have said a 63-year-old woman was admitted to their unit with a urinary tract infection and abrupt vision loss in her right eye.Scans revealed she had eye inflammation and lesions in her brain, particularly on the parietal lobe, a hub for processing sensory information.Doctors took two urine samples and also a sample from inside her skull.All three samples tested positive for Klebsiella pneumoniae – and two of these were an 'evolved' strain that was coated in a slime capsule, which researchers said made it able to dodge the immune system and proliferate in the body. Scientists are warning that a bacteria behind a urinary tract infection could cause a brain abscess