I've mentioned before that I work in a clinical lab.

Resistance is becoming more and more common. From the stats at work alone show an increase in ESBLs and carbapenem resistance in isolated organisms.

No idea where can we turn to if our drugs no longer works. I've heard of molecular research that aimed to shut down those resistance mechanisms to enable even the most basic penicillin to become viable again, I'll have to look that up.

Other than that, I do recall the Soviet researches based on bacteriophage that became obsolete due to mass-produced antibiotics in the troubled times of the 20th Century.