It should be helpful to get a culture. Rucy passed away before we were able to treat specifically based on a culture that was taken during her tooth extractions not too long ago. (she had reoccuring nasal, eye discharge, but it was more related to her tooth infections)
Though she passed before we were able to treat specifically based on the culture, the culture would have been very helpful. (This did not cause her death though) The culture showed bacterias that would have been best treated with other antibiotics on a long-term bases. Two of the preferred antibiotics were Penicillin Injections (not orally of course as that is toxic) and Chloramphenicol. Now these may not be suited for Bobby at all, but I am just mentioning the names that were to benefit RUCY only as an example of how a culture can help in creating a treatment plan that is suited to a particular bacteria type.
So it’s good to hear that your daughter’s vet is getting a culture done after the basic antibiotic didn’t work so far. Keep us updated!
Sending healing vibes for Bobby!