So I’ve been told for years that not emptying the bladder completely can lead to urinary tract infections (UTI) and this is one of the reasons catheters are used for people who cannot do so on their own. However, aside from the fact that catheters themselves are much more likely to cause UTI, I’ve never understood how retained urine in the bladder, which is sterile, can become infected with bacteria.
Where does this bacteria come from? With all other cases of UTI, the bacteria is introduced into the body from an unsterile, outside source (catheters, fecal matter, sexual partner, etc.). How does bacteria seemingly just materialize within a sterile environment?
Side note: I have been a paraplegic for 13 years and have never used a catheter and have also never suffered a UTI, despite maintaining, on average, about 100-150ml of retained urine in my bladder throughout that time (with no leaks or accidents).
Basically, the bacteria track up from the outside, from the opening of the ‘pee hole’ (urethral orifice) which is pretty close to the anus in women. So not too far for the bacteria to travel.
OTOH, men have fewer UTIs in large part because the distance from the opening to the bladder is greater. In other words, in men, there’s a longer trek for the germs to make to get into the bladder.
I don’t know, but poor eating habits, such as eating a lot of sugar, refined foods, wearing protective pads, (adult diapers) etc. are magnets for UTI infections, mostly in the elderly. I think there are many different combined reasons for one getting a UTI infection.
To help answer your question, voiding urine helps flush bacteria that inevitably find their way into the bladder. As bacteria accumulate they can adhere to the bladder wall, often through biofilm formation. Bio films often require shear numbers of bacteria to form. Once you have adherence it can be more difficult for your body to clear the bacteria through voiding urine and immune surveillance. Antibiotics are also less effective against bacteria that have formed biofilms.
So peeing often helps keep the number of bacteria down, if some should sneak in.
I’ve got some recent experience with this, and believe me, I wish I didn’t.
I just got over a UTI that apparently was a complication of a fairly large kidney stone that had been stuck in one of my ureters for something like 18 months.
The infection apparently got a toehold from a) blood entering my urine due to damge to the ureter from movement of the stone; b) urine retention related to the partial blockage of the tube.
The damn thing finally passed about five days ago. Yay. That plus about ten days of antibiotics seem to have done the trick.