Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. You haven t mentioned anything about your medical history but I suppose you must be suffering from COPD (chronic obstructive pulmonary disease) because your doctor prescribed prednisone with the antibiotic. Worse blood-streaked phlegm means that the initial treatment did not work particularly if you have shortness of breath as well. If you do have COPD then perhaps more advanced antibiotics might have to be employed. I usually prescribe a quinolone to patients with COPD and a respiratory tract infection with dirty phlegm. Moxifloxacin is the best choice for most patients but levofloxacin should work as well. For patients with bronchiectasis ciprofloxacin is usually recommended. Your best next step would be visiting your doctor for reassessment. Having experienced worsening after completing the treatment is a little worrisome and you shouldn t just ignore it. Hope I have answered your query. Let me know if I can assist you further.