makes sense, yes. although i don't know if i would go as far as calling that sense common. it requires a little deeper thinking. both of my parents are veterinarians, and while i'm in no way insinuating i'm speaking for all veterinarians, working at my mothers clinic and growing up with them, i got a lot of first hand insight as to why they and other vets in my area do things the way they do. they prescribe antibiotics because they work more often than not. if the antibiotics worked less than half the time (which would be the case if it were viral), they would start doing cultures more often. it would be a waste of antibiotics and leave you with unhappy owners and sick animals. if the antibiotics work, i would think it's safe to say it was a bacterial infection. and since antibiotics work more often than not, i think it would be safe to assume more often than not, these infections are bacterial. and while you do seem to hear about a lot of RI's not responding to antibiotics on here, i think that's probably because they've exhausted all other options and come here looking for answers. you don't hear of the hundreds of RI's that got treated and clear right up.