People who have recurrent urinary tract infections may have a chronic infection that is never fully eradicated, rather than having a new infection each time. Scientists have discovered that a strain of Escherichia coli that commonly causes urinary tract infections is able to burrow its way into the deeper tissue of the bladder. This may enable the bacteria to avoid the bladder's natural defences and resist eradication by antibiotics, potentially explaining why many people have recurrent infections …