urinary tract infection

Urinary tract infections (UTIs) are caused when bacteria enters, and then infects, the urinary tracts. Bacteria , typically Escherichia coli, living in your colon, are often the cause of UTIs. The bacteria enter through the opening of the urethra and then multiply in the bladder .

It is thought that the bacteria can be inadvertently spread from your anus to your 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 move upwards through the urinary tract, infecting your bladder (cystitis) and your kidneys (pyelonephritis).

The presence of bacteria in your urine does not necessarily mean you will develop a UTI. For example, many people, particularly elderly people, have bacteria in their urine without suffering any ill effects. This is called 'asymptomatic bacteriuria'.