Although this video doesn't ever call it "phage therapy", that's what they are really talking about. This is a very promising possible way of providing a real permanent solution to the problem of the evolution of antibiotic resistant bacteria and I assert should be given much more research and attention than what its currently getting.
The video mentions some impressive progress in giving it intravenously although its still vary much in the experimental stage for that. But, if they can find a regular way to make it work intravenously, they would have found a way to avoid what has so far been the main limitation of phage therapy which is in the past it normally can only be applied to surface infections and not deep-tissue infections and so far that has severely limited its range of medical applications.
And, if you are totally unfamiliar with the concept they are talking about, you can read this for a good basic introduction to it;
https://en.wikipedia.org/wiki/Phage_therapy
This video below gives me the idea of intelligently genetically modifying bacteriophages to make them even more effective;
Just one example of a child that was saved by phage therapy although it wasn't given intravenously;
I find this particularly interesting and it mentions some of the huge and interesting variety of bacteriophages evolution has produced;