Connie McManus writes:

>>The property of being acid fast is a diagnostic feature of the genus 
Mycobacteria and all species in this genus are intracellular parasites. They 
cannot reproduce outside of a living cell. They may float around in a 
moribund state, but that is not living and they most certainly cannot 
reproduce in such a condition. To the best
of my knowledge, there are not any acid fast bacteria that are associated 
with water. Can some be found floating in water somewhere?<<

They certainly can reproduce - most (though not all - notably Myco. leprae) 
grow well, though slowly, on acellular artificial media such as the classic 
Lowenstein-Jensen medium. Some certainly live in water, and I believe that 
some of them are soil microorganisms.

Bob Richmond
Samurai Pathologist
Knoxville TN