7 month old with chest rattling?

My 7 month old daughter has been on antibiotics for over a week due to the beginning of an ear infection, but she's also been sick for the same amount of time. She's coughed/puked up clear phlegm numerous times (around 10 times), but she STILL has the rattle and horrible coughing fits. If she has bronchitis, shouldn't the antibiotics have worked? And if it's not bronchitis, what do you suggest it could be? She's also taking cough medicine the doctor prescribed, but it doesn't seem to work for her.