In Georgia (Soviet Union) bacteriophages are used to to cure bacterial infection. In this video one can see how they are produced. So it might be possible in an alternate timeline, that Paul Ehrlich came up with this in the late 19th century. The right filter (Camberland filter) was available to get rid of the bacteria.
Then in the alternate timeline, this therapy is developed and becomes a standard treatment. Then antibiotics are discovered much later (because there already is a treatment) and later it is noticed that bacteria becomes resistant (to antibiotics) faster because of the use of bacteriophages.
Does this concept make sense?
EDIT: Note, the bacteriophage production is very different from the today medicine production. Instead of developing one pill after extensive testing, the production is very localised, i.e. every hospital has a bacteriophage production (and interchange them with other hospital). Moreover the hospital gives them out to every medical practice. Then if you have some bacterial infection the doctor test if any of his bacteriophage kills the infection, if not you get send to hospital where they have more bacteriophage, if no one helps either they produce new one as seen in the above video from minute 33 onwards (they get water from the local river and filter the bacteria out)...