I thought this was common knowledge? In my bio class ~20 years ago, people swabbed parts of the bathroom to see how far from the toilet you still found e. coli

I thought this was common knowledge? In my bio class ~20 years ago, people swabbed parts of the bathroom to see how far from the toilet you still found e. coli etc. And while this suggests it wasn't consistent, have always closed the lid / left the room since.