Well, I didn't have enough time to go into details when I made my initial post...good to see that some of the blanks were filled in, lol.
Rick: you said that you usually stop antibiotic treatment early (before the scheduled doses are used up). That is actually a bad idea as well - the duration of therapy is designed to ensure that the pathogens are killed. Not completing the course increases the risks of requiring further treatment, and of resistance.
Scott: aside from what was mentioned above, most of the injectable ABX (well, all of the ones I have dealt with) are nephrotoxic in reptiles. The decision to treat in such a manner is not without risk to your animals, and should not be taken lightly. If you don't know what you are treating, or even if there is anything to treat - you shouldn't be doing it.
I hate to say it, but this thread is actually a good example of the what I consider a big problem. The initial post was incomplete - it lacked important information. People responded based on what they read; then more additional information was added...significantly changing the picture. Those who frequent this site, have probably run across one of my little outbursts regarding the overuse, and misuse, of the term respiratory infection. It seems to be a growing issue, and, unfortunately, online forums are a big part of the reason. Well meaning people throw around words and suggestions that they do not fully comprehend...largely because somebody told them, or they read it someplace; usually without even bothering to ask basic history and husbandry questions. Then, as soon as people see a similar description, they are jumping on the bandwagon...telling others how to deal with their problem. The piece that the question askers overlook is that they have no idea who is giving them advice. In many cases, I see people authoritatively responding to threads when they have kept snakes for a mere 6 months...and their first posts were with common problems (and frequently, the snake died and has been replaced).
OOPS - guess I got off on a bit of a tangent...sorry all. Back to the issue at hand - empiric antibiotic therapy is not indicated based on what has been stated in this thread. If there is more information, feel free to provide it
**please note - the "well meaning people" referred to above is not describing anybody in particular, nor aimed at anybody that has already posted on this thread**