hi , thanks for your question i completely understand your problem actually in respiratory tract infection antibiotic is mandatory if sputum is purulent and choice of antibiotic depends. treatment starts with an empirical antibiotic after that if the patient is not responding we send a sputum pyogenic culture and senstivity according to which we can specifically know the pathogen and we can also know the antibiotic which will kill that organism causing infection . u can continue with the same antibiotic or else start on with a new second generation cefalosporin adter consulting a pulmonologist who can always guide you better u can wait for a day or two to see the response. thanks/ regards feel free to ask more questions may god bless your family a good health