Urinary tract infection

Urinary tract infection is one of the commonest infections to affect humans. Uncomplicated infections occur most commonly in otherwise healthy women when uropathogenic bacteria, usually Escherichia coli, ascend from the perineum into the bladder and overcome host innate immunity. Complicated infections occur in patients with an anatomical or functional abnormality of the urinary tract. The diagnosis is made on the basis of symptoms and diagnostic precision is improved by urinalysis. Urine culture is important with severe, recurrent or complicated infection and when the diagnosis is unclear, for example, in children and the elderly. Most women with symptoms that resolve quickly do not require further investigation but in children, men and patients with recurrent or severe infection, imaging of the renal tract, functional testing and cystoscopy should be considered to exclude an underlying abnormality. Empirical antibiotic treatment started on the basis of symptoms and directed by urinalysis is suitable for uncomplicated cystitis but should be altered based on culture results for more severe infections. Three days’ antibiotic treatment is usually sufficient for uncomplicated cystitis in women. Long-term or post-coital antibiotics are effective treatments for patients with recurrent infection in whom non-antibiotic strategies have failed.