Almost every organic molecule has a mirrored counterpart, like a normal screw and a left-handed screw.
Almost none of them occur in the nature.
So we have the technology to synthesize them now, and synthesize a bacteria out of them.
But if you do that, and the bacteria escapes, all your existing medicine will be useless, so you need to re-synthesize all your antibiotics in left-hand configuration.
That typically does not happen with regular bacteria experiments, because most of what you can synthesize in the lab will be a descendant of some other well-known bacteria, which already have an appropriate medicine to treat it, and in most cases it will be effective against your new strain.












In theory yes. In practice no one wants to try it.