I'm not familiar with that particular antibiotic injection so I don't know how it normally reacts in pets. I looked it up and meant to ask the big boss about it but forgot.

Only things I can think of is a culture/sensitivity test on the nasal passage to see if bacterial infection or not and which antibiotic would work best.

Not being familiar with that antibiotic I'd wonder if it's so long lasting is it ok to switch over to Baytril just a few days after injection? Maybe it's fine, like I said I'm not familiar with that one. Now Baytril I know, I used to have to give Dusty injections with that when she'd get a respiratory infection.

Sorry I'm not much help to you.