Most urinary tract infections (UTIs) are caused by bacteria that live in the digestive system.
It is thought that the bacteria can be spread via the anus (the opening through which stools are passed out of the body) to the urethra.
This can happen if, when wiping your anus after going to toilet, the toilet paper comes into contact with your genitals. The bacteria can then multiply and move through your urinary tract causing the following possible infections:
- Infection of your urethra (urethritis). The urethra is the tube that runs from the penis or vagina up into the bladder, through which you urinate.
- Infection of your bladder (cystitis). The bladder is a balloon-shaped organ used to store urine.
- Infection of your ureters (ureteritis). The ureters are tubes that run from the bladder to the kidneys.
- Infection of your kidneys (pyelonephritis). The kidneys are two bean-shaped organs that are used to remove waste products from your blood and convert them into urine.
Risk factors
Women are more likely to develop a UTI than men. This is because a woman’s urethra is located closer to the anus than a man’s, which makes it easier for bacteria from the anus to reach the urethra. The female urethra is also much shorter than the male urethra (which runs through the penis), making it easier for bacteria to reach the bladder.
You are also more likely to develop a UTI if:
- You have a condition that obstructs or blocks your urinary tract, such as kidney stones.
- You have a condition that prevents you from fully emptying your bladder. If urine stays for too long in the bladder it provides an environment that allows bacteria to thrive and multiply.
- You have a weakened immune system, for example, because you have diabetes, or are undergoing chemotherapy (medication to treat cancer).
- You are female and sexually active. Sexual intercourse can irritate the urethra, allowing bacteria to travel more easily through it and into your bladder.
- You are male and have an enlarged prostate gland. If the prostate gland is enlarged, it can place pressure on the bladder and urethra, preventing the bladder from emptying fully.
- You have a urinary catheter, which is a tube that is inserted into your bladder to drain away urine.
- You use a diaphragm. Diaphragms (a barrier form of contraception that sits inside the vagina) can place pressure on the bladder, preventing it from emptying properly.
- Your sexual partner uses condoms coated with spermicide. The chemicals in spermicide gel can irritate the vagina making it more vulnerable to infection.
