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MAC resistant to ethambutol and intermediate resistance to rifampin
I was diagnosed with MAC via sputum cultures and CT scan 7 years ago. I had relatively few symptoms at the time except recurrent bouts of pneumonia. I was placed on azithromycin, ethambutol, and rifampin M, W, F for 5 years. Sensitivity testing showed susceptibility to azithromycin, resistance to ethambutol, and intermediate susceptibility to rifampin. ID doctor at the time said it was only important that MAC was susceptible to azithromycin.CT scans remained relatively stable, although I was diagnosed with bronchiectasis during that time and they still showed MAC nodules.I was taken off meds 2 years ago. I had a severe bout of pneumonia last December and was hospitalized in May after a bronchoscopy (fever, chills , CT much worse). Sensitivity testing showed MAC sensitive to clarithromycin but testing was not done for ethambutol or rifampin. I was again started on azithromycin, ethambutol, and rifampin(this time daily) 2 months ago by a new ID doctor. At my last visit, I showed him notes from my last doctor showing initial sensitivity testing. He sent me to another lab to get sensitivity testing on rifampin and ethambutol, saying that may be why I was a treatment failure before. Have I wasted another 2 months of treatment with the wrong meds or was my first ID doctor correct in his assertion that the macro life was the only drug where sensitivity was important.
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Few things here.
First this might not be the same MAC as previously- a new infection is more likely, so sensitivities might be different. It’s good that you’re getting them checked now but they should also check for amikacin to see whether it is an option to add Arikayce- usually at the six month mark if you haven’t responded to the standard Big 3
The side effects of Arikayce can be tough initially but many of us have had good responses. My cultures cleared at two months after it was added.
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Hug
3 ReactionsI had a different species of mycobacterium at one point in my journey, it was not sensitive to ethambutol but it was sensitive to amikacin, so I used that as a neb for over a year. In my case, as I understand it, I have been colonized with micobacterium and it will never go away. I need treatment for it when I am severely immunocompromised from myeloma treatment. Currently my MM is in remission, so no treatment for either. If (when) MM comes back I’ll have to have treatment for both.
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Hug
1 ReactionThank you. Unfortunately, also resistant to amikacin. Wish you well.
Thank you for the information.
Hi Debbie
Was it absolutely resistant to amikacin?
I seem to remember my bug was only moderately sensitive in lab but I responded anyway
Good luck
It showed intermediate resistance, 32 MICs, which means, I believe, my dose would have to be much higher. My ID doctor had said previously he would not want to use it for that reason. Sensitivities done in 2017 showed it was susceptible to clofazamine if this is still the same infection. I guess I will have to wait and see what the new testing shows and go from there.
I believe my doctor’s cut off was 64 and I responded at the same MIC as you.
The lab numbers are generally an indicator of clinical response, not absolute .
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1 ReactionSensitivities were done last week. Keeping my fingers crossed but will have to wait and see. Thank you.