[robocat]

> Why do you think the strongest of the strong bacteria are found in hospitals?

I presume you mean strong against antibiotics and sterilisation. The evolved bacteria are likely weaker along other dimensions (that are less important for survival in a hospital setting). Some evolution is compromises, improving X has cost Y.

Aside: the mega-plate video is an unbelievably good demonstration of bacterial evolution: https://m.youtube.com/watch?v=plVk4NVIUh8 especially note the tree at the end showing how many different mutations evolved.