I can't imagine the rate of mutation is higher for these colonies than, eg. those that are in your own gastro-intestinal tract. The difference is with the lab c

I can't imagine the rate of mutation is higher for these colonies than, eg. those that are in your own gastro-intestinal tract. The difference is with the lab colonies they don't have the same selection pressure as bacteria in the wild. So my naive understanding is that they would actually be less fit in most environments outside the lab. For example, how fast they grow - the mutated growth strategy is probably optimised to the lab conditions and could result in an unviable lineage outside of the lab. Even accounting for the generation of dangerous (to humans) mutations, the benefits gained from our increased understanding of bacterial lineages and genetics almost certainly outweighs the danger.