Urine is usually sterile, which means it does not have any bacteria, viruses or fungi present. A UTI can occur when a microorganism enters the urinary system through the urethra. Most infections are caused by Escherichia coli (E. coli), which is a digestive tract bacterium that lives in the colon, and spreads to the urethra from the anus. Other microorganisms, including chlamydia and mycoplasma, can cause UTIs in men and women, but these UTIs are usually restricted to the urethra and the reproductive system. Since these microorganisms are sexually transmitted, both partners will need treatment when infections occur.
Other causes that increase the risk of UTIs include:
- Structural abnormalities of the urinary system, urinary stones and bladder obstruction.
- People with diabetes have more sugar in the urine, which can lead to UTIs.
- Men with an enlarged prostate are unable to empty their bladder completely.
- Babies born with abnormality in the urinary system have a higher risk.
- Women have a shorter urethra, thus allowing bacteria to reach the bladder more easily. Women’s risk usually increases when they become sexually active and after menopause due to the dry state of the urethra and vagina. 1 in 5 women develops a UTI during her lifetime