A tract infection could be a bacterial infection of the bladder (cystitis), the kidneys (pyelonephritis), or both. Normal urine contains no bacteria (germs).
Sometimes, however, bacteria from outside the body gets into the tract and cause infection and inflammation.
This is a tract infection (UTI), which may involve the channel (a condition referred to as urethritis), kidneys (a condition referred to as pyelonephritis), or bladder (a condition referred to as cystitis). Cystitis is that the most common style of tract infection.