Sorry to be negative about your doctor, but if you have bronchiectasis and are coughing up large amounts of sputum and you have an infection and doxycycline didn't help, you NEED a sputum culture (not just an AFB slide test) to determine exactly what bacteria is in your lungs so it can be properly treated.

Prescribing doxycycline will do nothing for the two most common bacteria to infect people with bronchiectasis - Mycobacterium Avium Complex (referred to as MAC or NTM) or pseudomonas. And probably not for staph or strep, the other two frequent culprits which tend to be doxycycline resistant when in the lungs.

A sputum culture means they do 2 specific tests on your sputum in your usual lab - to check for the presence of mycobacteria. My lab also tests for staph and strep at the same time. If either NTM or Pseudo is found, the specimen is sent to a specialty lab to be grown in an incubator for up to 8 weeks. This will show exactly what "bug" it is, and then they test to see which antibiotics have an effect on it.

Also, if you have Bronchiectasis and a lung infection, oral prednisone is not usually prescribed because it can suppress your body's natural ability to fight infection.

If your doctor doesn't understand this, it means they are not familiar with Bronchiectasis and NTM, and you will probably need to see someone else. This does not mean they are not a good doc for others, but few are experienced in treating MAC & Bronch because they are quite rare. If you cannot change pulmonologists, perhaps you can be referred to an infectious disease doc for consultation.

Do you have the option of changing doctors?