Well they sensitive to man-made antibiotics which by definition are modern antibotic drugs, and substances they've had no exposure to. But it has resistance to

Well they sensitive to man-made antibiotics which by definition are modern antibotic drugs, and substances they've had no exposure to. But it has resistance to many naturally occurring anti-biotics, which would suggest some exposure to develop resistance. And there's probably some telltale differences between acquired resistance and natural immunity because your structure is such that you're not vulnerable. I think if you had more knowledge about the subject you'd understand how your idea isn't as plausible as it sounds.