I have mrsa in my spine(osteomyelitis). Damn stuff is trying to kill me.
The best bet against MRSA, necrotizing fasciitis, and XDR-TB are likely to be bacteriophage viruses, which have tantalized scientists for decades now.
That is, the vast majority of all viruses attack bacteria, but they are incredibly picky about which bacteria a given virus will attack. If they could just find the right virus, it would take out that particular bacteria in the body without harming a person.
And nothing is ever easy.