Sterility of urine

The idea that urine is sterile is a misconceptionhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3957746/, even before it comes out of you and gets contaminated by your skin. Bacteria are present at low levels in the urine of healthy people not suffering from a urinary tract infection, Evann Hilt of Loyola University of Chicago reported May 18, 2014 at a conference of the American Society for Microbiology.
It appears that the urban legend about urine being sterile has its roots in the 1950s, Hilt says, when epidemiologist Edward Kass was looking for a way to screen patients for urinary tract infections before surgery. Kass developed the midstream urine test (still used when you pee in a cup) and set a numerical cutoff for the number of bacteria in normal urine: not more than 100,000 colony-forming units (cell clusters on a culture dish) per milliliter of urine. A person tests “negative” for bacteria in their urine as long as the number of bacteria that grow in a lab dish containing the urine falls below this threshold. “It appears that the dogma that urine is sterile was an unintended consequence,” Hilt says.https://www.sciencenews.org/blog/gory-details/urine-not-sterile-and-neither-rest-you
If urine isn’t sterile, does that mean you shouldn’t pee on a wound? Well, that was probably never a great idea anyway. If you don’t have clean water, you’re generally better off letting blood flow flush a wound, bathing it in infection-fighting white blood cells.
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