Very important question.
As soon as you say evolution is over, some bloke comes along with a sheaf of research about bacteria evolving in modern hospitals, turning into “superbugs.”
Yes, but it’s not a change of body plan. It’s a point mutation, if even that. More likely it’s a repeating loop of the existing genetic resistance to oxidation, which is built into all living creatures (and is advertised on all your vitamin shelves as antioxidants.) Antioxidants are essential to life because we are all under oxidation attack all the time, especially the ones of us who breathe air, but the ones under water too. A bacterium with a double (triple, quadruple) set of oxidation resistance factors can activate more effectively in a hostile environment.
However, put the superbug in competition with the more economical bacterial genome having only one such factor, and the simpler bacteria, multiplying faster, will win hands down – unless you are in a hospital setting or in an overly anti-bioticized population whose water supply is polluted with killer medicines — read “oxidant medicines” — and antibiotic cleaners.
Stop using antibiotic soap; rinse your hands with yogurt.
In any case, the superbug is not a change of body plan, and it can be bred out of a population as well as bred in. Read Oxygen, the Molecule that made the World by Nick Lane.
Evolution never reverses: no bony fish ever devolved into a shark type; no bird ever devolved into a dinosaur type; no frog ever went fully home to the ancestral water; even the whale is still thoroughly a mammal. Evolution is a one-way street, and bacteria change a little but do not evolve.
Remember: micro-evolution is not evolution, because it does not produce new species; macro-evolution leads (or used to lead) to new species by rearranging the chromosomes, not just the genes, into new body plans.