Understanding Urinary Tract Infections (UTIs)

Most UTIs are caused by bacteria, although they may also be caused by viruses or fungi. Bacteria from the bowel are the most common source of infection. The infection may start because of any of the following:

• Sexual activity. During sex, bacteria can travel from the penis, vagina, or rectum into the urethra. 

• Bacteria on the skin outside the rectum may travel into the urethra. This is more common in women since the rectum and urethra are closer to each other than in men. Wiping from front to back after using the toilet and keeping the area clean can help prevent germs from getting to the urethra.

• Blockage of urine flow through the urinary tract. If urine sits too long, germs may start to grow out of control.

Parts of the urinary tract

The infection can occur in any part of the urinary tract.

• The kidneys collect and store urine.

• The ureters carry urine from the kidneys to the bladder.

• The bladder holds urine until you are ready to let it out.

• The urethra carries urine from the bladder out of the body. It is shorter in women, so bacteria can move through it more easily. The urethra is longer in men, so a UTI is less likely to reach the bladder or kidneys in men.

What are the symptoms of a urinary tract infection?

• Frequent urination
• Pain or burning when passing urine
• Fever
• Urine looks dark, cloudy, or reddish in color. (Blood may be present in the urine.)
• Urine smells bad
• Feeling pain even when not urinating
• Tiredness
• Pain in the belly (abdomen) area below the bellybutton, or in the back or side, below the ribs
• Nausea or vomiting
• Have a strong urge to urinate, but only a small amount of urine is passed
• Women may feel an uncomfortable pressure above the pubic bone
• Older adults can have a change in their mental state, such as confusion or severe lethargy