> The hills are alive...
True. Topsoil is several percent bacteria by weight.
> What assurances do we have that the bacteria won't mutate, self-replicate, or
> turn against its master in the form of some horrendous new super-bug that
> makes the 20,000 land-mine casualties a year seem like a drop in a bucket?
None. And the sames goes for the millions of other species of bacteria that infest every square meter of the Earth's surface.