Urinary tract infections (UTI’s) are one of the most common reasons people go to get medical treatment. There are an estimated 5-10 million outpatient visits and over 250,000 hospital admissions due to UTI’s. Around 10% of people will get a UTI in their lifetime.

The urinary tract is broken down between the upper urinary tract (ureters and kidneys) and lower urinary tract (bladder and urethra).
The urethra is colonized with some types of bacteria at the distal portion; lactobacilli, Corynebacterium species and Staphylococcus species among others. All areas above the urethra are sterile in the normal healthy person.
The anatomy of the female urethra is of importance in the cause and prevalence of UTI’s. The female urethra is quite short compared to the male, and its close proximity to the perineum area, which is abundant with bacteria that come from the gastrointestinal tract, makes it more susceptible to infections.
In males, UTI’s are most common in the first year of life and not again until around 60 years of age when prostate enlargement interferes with the emptying of the bladder.
In women, where the majority of UTI’s occur, the prevalence increases gradually with age. In sexually active women, reinfection is seen in up to 50% of the time. There is a definite association between UTI’s and sexual intercourse because sexual activity increases the chance of bacterial contamination of the female urethra.
Also in women, hormonal and anatomical changes as what occurs during pregnancy increase the incidence of bacteria in the urine.
UTI’s are important complications of diabetes and renal disease.
There are four main types of UTI’s:
- Urethritis
These are usually associated with sexually transmitted infections like gonorrhea and Chlamydia. Painful or difficult urination and frequency are the most common symptoms. - Cystitis
This is an infection of the bladder. Common symptoms include painful urination, frequency and urgency. Urine may be bloody, cloudy and have a bad odor. Fever is rarely seen since it is a localized infection. - Acute Urethral Syndrome
This occurs primarily in young, sexually active women. They experience many of the same symptoms and same bacteria as in cystitis, however urine cultures may reveal fewer bacteria. An important feature of this infection is white blood cells in the urine. - Pyelonephritis
This is an infection of the kidneys. Typical symptoms of this type of UTI are fever and flank pain. This is the most serious form of UTI.
The bacteria that cause UTI’s are numerous with E. coli being by far the most common cause.
How do the bacteria get to an area and cause a UTI? There are 2 major ways; ascending and blood borne:
- The ascending route is easily the more common, particularly in females. The bacteria colonized on the perineum gain access and ascend up the urethra into the bladder. Here they can multiply and pass up the ureters to the kidneys.
- The blood borne route occurs because of bacteremia. Here the kidneys get seeded with bacteria from the bloodstream. This way accounts for less than 5% of UTI’s.
Most UTI’s are easily treated with antibiotics. Products like AZO and others will not get rid of the infection just relieve symptoms like painful urination. Antibiotics are still necessary.
How can you prevent getting UTIs? You can drink plenty of water and other liquids like cranberry juice (as long as you are not taking certain blood thinners).
Females should wipe front to back to prevent contaminating themselves with possible fecal contamination. Also urinating after intercourse to flush out bacteria can help.
Originally published on August 15, 2009
A good and comprehensive read. Also an important point to include here is that untreted UTI can lead to Bladder and Kidney infection and can lead to permanent damage to one or more kidneys.