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'.
That's part of it, but this is something governments have to take leadership on right now. That will only happen with direct pressure. Waiting until it's the leading cause of death will be too late, because of drug development pipeline timeframes.
You'd think the companies behind creating this technology would welcome the never-ending arms race. They get to keep releasing products while their old ones get cannibalized for them.
Stuff that kills bacteria has to also not kill people.
I saw a TV programme where scientists had a big tray of nutrient gel. They divided the tray into sections. The fist section was normal nutrient gel. The next contained a normal dose of antibiotic. The next section was 10x, the next section was 100x and the final section was 1000x a regular dose. This was far more than humans could tolerate. They stopped at 1000x because that was the limits of solubility - they couldn't disolve more antibiotic into the gel.
Scientists then dropped a bit of e.coli on the normal gel and set their time lapse cameras.
In just a few weeks the bacteria had evolved to live on all sections of the gel.
(This was a BBC 'Horizon' programme called "defeatng the superbugs")
Worth noting: the bacteria at the end are not the same as the bacteria at the start.
Antibiotic acts on a particular mechanism to kill the bacteria. In order to overcome an antibiotic threat, bacteria have to either modify or drop any functions associated with that mechanism.
If any of those functions help them to infect humans, then the bacteria at the end of the process will be generally less able to infect humans.
