Welcome in H.C.M.
I have considered all the facts of your medical history and the two episodes of pneumonia
in last 10 months along with change in colour of your sputum.
No doubt change of colour from dark yellow to white is a good sign. But we are concerned with erradication of pathogens so please do culture and sensitivity of phlegm to see weather it is sterile or not.
Here I would like to tell you that in recovery we should consider the natural immunity of your body as well along with your natural antibiotic.