antibiotics not working

Question
One of my rats has been on Doxycycline and Baytril for 12 weeks now. It helped at first, but he still sounds congested sometimes. So i added Amoxicillan to his meds in case it was an infection, and it's been almost 3 weeks but sometimes his breathing still sounds raspy and wet. (I use safe bedding) He's never had a very good immune system. But there must be something else i can do. Why won't he get better? What should i do?
Joleen

Answer
Rule of thumb: If antibiotics dont work within 3 days, its time to switch. Antibiotics work within 24 hours and the symptoms start to subside within 3 days.  If the medication isnt working, a new drug should be used. Using them when they do not work does nothing but cause a tolerance to the drug and the bacteria will soon be so immune to this drug (s) it wont do a thing.  Chances are your rat doesnt even have infection but instead, has lung scarring or possibly COPD from chronic mycoplasmosis.  Let me ask...when he first became sick, how long ago was this and what was the treatment plan, if you can remember? This will help me know if your rat has lung damage or active infection.  If he was not treated properly by the Vet the very first time he had a respiratory infection, chances are his lungs are damaged and what he needs now is steroids for inflammed lung tissue and albuterol to help dilate his airways to help him breathe better.  Nebulizing will help immensely.