mouse emergency

Question
Hi,
My small female mouse Victoria seems to be chirping/sneezing/weezing all the time. She is less than a year old, very small, and her coat color is brown. Very adorable, lovable, but ill. I took her to the vet thinking it was a respitory infection, they gave me some antiboitics to give to her orally twice a day. However, her health has not improved, and it seems her cage mate Rose has caught the same thing she has all of a sudden. Rose was never sick until victoria started developing these symptoms..which is why i assume it's contagious. But at this point i dont know what to do. I switched their food incase it was allergies, and there bedding is carefresh (the white kind, because it has less dust) and i always freeze it for 48 hrs to kill any possible mites. I'm not sure what it could be, or why the medicine isn't working. I am at a loss of ideas, and I desperatley need someone to give me an idea of what is going on with my adorable little girl mice. Any advice you can give I would REALLY appreciate it! thank you!!
-Samantha

Answer
Dear Samantha,
thank you for your question.
Mice are very prone to respiratory infection. In many cases, they are caused by Mycoplasma, which probably all mice carry and which only causes smyptoms when the mice are stressed or weakened for some reason.
http://en.wikipedia.org/wiki/Mycoplasmosis

Antibiotics are the medication of choice for this, but it's possible that the germs are resistant to the particular antibiotic the vet gave you. It's best to try another antibiotic, there are several that are suitable for mice. Doxycycline for example is a powerful antibiotic, although your vet may want to try other choices first that are less aggressive.
I hope I was of some help to you
Jennifer