@margiebanks There will be a suseptibility test result along with your mac results. That test will tell which antibiotics will work best against your strain of mac. I agree, it is good to save the really strong antibiotics as a last resort because you don't want to run out of options. My doctor told me back in 2013 that he didn't want me on zithromycin. He wanted save that as a big gun later in life if I need it. In the last 15 yrs, all of my doctors used toput me on it at least twice a year. My dr said that is not a drug you would want mac to become resistant to.