Positive-Negative-Positive MAC Cultures: Treatment Duration

Posted by bf @bfpa, Jul 27 11:25am

I would appreciate your guidance regarding the duration of my MAC treatment.

I started treatment in August. Was told I did not have to retest after my 5 negative results but started to feel bad again in November/December. Recently submitted new sputum samples. I am currently waiting for those culture results.

My sputum culture history is:
June: 3 positive cultures (before treatment)
Started treatment in August
September: 3 negative cultures
October: 2 negative cultures
February: 2 negative cultures
March: 1 positive culture

I also have bronchiectasis. While I do not cough frequently, I continue to experience chest tightness when breathing and have lost approximately 12 pounds since starting treatment (about 1–1.5 pounds per month).

I have received conflicting recommendations from two pulmonologists. One feels I can stop treatment, while the other believes my 12-month treatment period should restart from the positive culture in March. Given my culture history, bronchiectasis, ongoing symptoms, and weight loss, I am concerned about stopping treatment too soon because I want to do everything possible to prevent the MAC from recurring.

Based on my positive–negative–positive culture pattern, how would you recommend determining the appropriate duration of treatment? Should the 12-month period be counted from my initial culture conversion, or does the positive culture in March change that recommendation? Does the answer depend on the results of my current sputum cultures?

Thank you very much for your time and guidance. I greatly appreciate your expertise.

Interested in more discussions like this? Go to the MAC & Bronchiectasis Support Group.

Sue, Volunteer Mentor | @sueinmn | Jul 27 1:02pm

@bfpa It is customary to repeat imaging after 6 months to a year of treatment to see if there is evidence of decreasing infection. Years ago, I was in that positive-negative-positive pattern, but my CT scan showed the nodules resolved AND I was experiencing severe gastro issues and excessive weight loss (over 20% of body weight) so we chose to stop the antibiotics.

Fast forward over 6 years, with daily airway clearance & (now) occasional saline use, my cultures continue to be negative and scans show no sign of infection or progression of bronchiectasis. Your results may be different.

Are you doing daily airway clearance?

bf | @bfpa | Jul 27 2:29pm

@sueinma I started doing airway clearance twice a day about 3 weeks with nebulizer and Aerobika. So far I have noticed no difference.

The last CT I had was in Jan. It said there was interval improvement but persistent multiple tiny nodular opacities. In March had a CT for another reason and they noted multiple bibasilar pulmonary nodules measuring up to 1.2 cm in the right lower lobe.

Thank you for your insights.

reneemc | @reneemc | Jul 28 11:51am

The positive culture in March would reset the treatment duration according to guideline based therapy. Twelve consecutive months of negative sputum cultures are recommended.