The biggest problem with phages is they can be quite specific. Antibiotics put phage research out to pasture because a single, easy to mass produce small molec

The biggest problem with phages is they can be quite specific. Antibiotics put phage research out to pasture because a single, easy to mass produce small molecules were capable of wiping out enormous varieties of bacteria. With phages you'd need a large library to counter different bacteria, you'd have to successfully identify the bacteria which is causing the problem which may require culturing. If you wanted to maintain phage effectiveness in a heavily selected environment you'd also need to design phage "reactors" where the phages can be continually evolved against current bacterial populations.