I hear urine is sterile but can it harbor bacteria or viruses?

Question

Say if urine is left to sit will bacteria thrive in it or is it toxic to them or inhospitiable.

Answer 1

Urine itself is sterile inside of the body due to it's naturally acidic nature. But, bacteria can travel up the urinary tracts to the bladder from the outside of the body (such as not wiping correctly after one uses the bathroom) and since bacteria likes warm, dark places it can thrive there. This is how Cystitis and UTI's come about.

Of course urine can harbor bacteria outside of the body. If it's left to sit in a cup and absorb naturally occuring bacteria from the environment, it will thrive there as well.

There are some ways urine can be changed to make it more inhospitable to bacteria. Drinking a glass of cranberry juice per day will keep the urine acidic, which will make it harder for bacteria to thrive in it. This is why doctors tell UTI sufferers to keep the cranberry juice intake up.

Answer 2

some bacteria can definitely grow in urine. It is not a germicide.