most utis are caused by:
Urinary tract infection Description. An in-depth report on the causes, diagnosis, treatment, and prevention of urinary tract infections. Alternative Names. Cystitis; UTI. Highlights. Urinary Tract Infections (UTIs) Urinary tract infections (UTIs) are a common type of infection caused by bacteria (most often E. coli) that travel up the urethra to the bladder. A bladder infection is called cystitis. If bacterial infection spreads to the kidneys and ureters, the condition is called pyelonephritis.