From my limited expertise regarding antibiotic resistant diseases:
The strain that is resistant often, if not always lose viability(effectiveness in surviving) in an environment without the antibiotic present.
It's kind of like you got 100 mil $
Group 1: (none resistant strain) AK-47 all the way!
vs.
Group 2: (resistant strain)Many AK-47 some anti tank and AA-weaponry body armour, armoured military vehicles, fortified command centers etc.
The difference between group 1 and group 2 are
Group 1 can recruit/support more men for the same amount of resources thus being able to cover more of an area
Group 2 has the benefit of being able to not only survive/resist police and the local under equipped military(aka. antibiotic) but defeat it.
The point is that Group 1 would still win a direct competition about influence/power/resources unless opposed by organized well equipped and trained forces(antibiotic)
The grimmest but probably safest way to deal with antibiotic resistance is to stop using the antibiotic for a few decades and let the resistant strain lose in the internal competition with the none-resistant strain(s).
But that is VERY dangerous if it goes wrong, some would say it is too risky, there's a possibility that Group2 manages to mutate a sustainable strain, that might even fed upon Group1
Just like a paramilitary group taking power then keeping the lid on group1 with strong arm tactics.
Edit1: Last two paragraphs are a bit contradictory, edited text added in red, no text has been removed.