Excellent question.
I am working on the other side of the story (Heretic!) as i work with Antibiotics and how to use them more carefully etc.
I would say the biological antibiotics can be harmful too of
course. I would like to take the problems of antibiotics to three sub-problems, and one is the microbiom (other to is simply pharmacological interactions and side effects and the resistences).
If you treat something that is mostly a bacteria alien for your body or a
local citizen going rogue due change in the body, of course the first one is easier because it doesnt belong to you but still i can hardly imagine any compound which kills only on type of bacteria so there is always a change in the microbiom. Always. We are getting to understand the importance of the microbiom and that almost everything is connected to it, so change it and the consequences will be there, we just cannot tell the dimensions yet.
And just regarding to the other to risks: biological, herbal antibiotic compounds have those risks too! Therefore i would suggest absolutely the same caution using them! They can induct harmful interactions and presumably also resistences (however the influence to the antibiotics is unclear.
Ceterum censeo use every kind of antibiotics regerdless of source!