The one limit seems to be that even if we did that the bacteria will evolve to become resistant against those as well. This is a game of leap-frog, we've been ahead for a while, now we'll be behind for a while and so on.

Think of it as a very slow arms race where on the one side there is intelligence and design and on the other there is the lottery driven mechanism of evolution that rewards the solver of the newly posed problem with a very large number of offspring.

The sides are surprisingly well matched and short of total eradication this is likely going to be the game for the next foreseeable future.

The bigger challenge will be to restrain ourselves to consume much more limited amounts if and when we do find antibiotics that work again in order to lengthen the time that we're 'on top'.