According to MedlinePlus, urinary tract infection symptoms typically resolve within 24 to 48 hours when treated with antibiotics. UTIs that have spread to the kidneys may take one week or longer to clear up with proper treatment. Chronic urinary tract infections often require longer courses of antibiotics.
WebMD explains that in most cases, urinary tract infections are not considered dangerous but can lead to severe kidney damage if left untreated. Symptoms of a UTI can include pain upon urination, fever, nausea and foul-smelling urine. Urinary tract infections are often caused by bacteria found in bowel movements that enter the urethra and make their way into the bladder.