Comment by txrx0000

The planet is teeming with non-mirror things at every trophic level.

The mirror bacteria has to somehow perfectly dodge all of the countless non-mirror things that can kill it (even unintentionally, like a byproduct molecule that just happens to blow it up or get in the way of reproduction), but somehow still be able to execute its own mirror-biomechanism to kill non-mirror things. And every step of the kill mechanism would also have to perfectly dodge non-mirror things interrupting it.

Not that it can't be done in theory, but it would be easier to just make a normal superbacteria, or maybe even nanobots.