I'm not sure which is more disturbing; that news regarding the amazing durability of some strains of Mycobacteria...or the almost certain knowledge that there is someone, somewhere out there, who will actually start going through gallons of alcohol to sterilize everything in sight, just in case.
Life is a risk; it cannot and will not ever be entirely safe, neither for our fish nor ourselves. We all have to accept a certain level of risk, whether we like it or not, just to get through each day.
I knew a lady in Ontario who sterilized everything by boiling; wood, rocks, substrate, hardware, new or used, didn't matter. When she learned that some rocks can apparently explode when boiled due to trapped water within them...I don't know if that's really a thing, but it's supposedly a well-known "fact" in some circles...her response was to get a dedicated pressure cooker for use strictly as a sterilizer.
I always felt bad for her dog; I leave it to your imagination what an un-dog-like life it lived.