Hi Dulwitch...I think before they start u on the big 3 they have to do 3 sputum samples to confirm a proper diagnosis..my sputum recently showed another bacteria same family as yours, starting with F...they r doing more sputum to grow culture again...they will only put u in the big 3 with s confirmed diagnosis..sometimes bacteria shows up randomly and disappears...I’ve been on big 3 for 14 months..quite tolerable👍🏼