Ok, this is kind of a broad question since there are so many different species of them (in various biological kingdoms, at that). What is it about their physiology that allows them eat something that contains bacteria strains that would kill most other creatures in even a small quantity?
I assume they must have some kind of mechanism in place that keeps the bacteria from ever getting into their blood stream in the first place. Or maybe they have some kind of souped up immune response. It would seem worthwhile to the field of medicine to study that if they did. For some reason that didn’t seem very likely to me, but I have to profess ignorance on this one.