Patients with bronchiectasis on long term macrolide therapy were at low risk of developing macrolide-resistant Mycobacterium avium complex (MAC) disease, according to the results of a recent study published in the journal CHEST.

Researchers collected data from patients with bronchiectasis on long-term macrolide therapy via the United States Bronchiectasis Research Registry. Patients were included in the analysis if they had a documented negative nontuberculous mycobacteria (NTM) culture. Furthermore, patients were stratified into 2 groups, those on macrolide therapy at the time of the baseline visit and those not on macrolide therapy. The percentage of patients with at least one positive NTM culture at the 1-year follow up visit was compared between groups.

Among the 410 patients in the Bronchiectasis Research Registry with no history of NTM culture, 91 categorized in the macrolide group and 319 in the nonmacrolide group. Of the patients in the macrolide group, 3 (3.3%) had at least one positive NTM culture — 2 patients with MAC and 1 patient with M chelonae/abscessus. This compares favorably to 44 of 319 (12.5%) patients in the nonmacrolide group having at least one positive NTM culture. Further, patients in the macrolide group had lower odds of a positive NTM culture at the first follow-up visit (odds ratio, 0.21; 95% CI, 0.06-0.70; P =.005).

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“Concern regarding macrolide-resistant NTM may limit utilization,” the study authors wrote. “These results, while preliminary in nature, suggest that in addition to current indications, there could be a role for prophylactic long-term macrolide therapy in [patients with bronchiectasis] at high risk of NTM pulmonary disease.”


Metersky ML, Choate R, Bronchiectasis and NTM Research Registry Investigators. The association of long-term macrolide therapy and nontuberculous mycobacterial culture positivity in patients with bronchiectasis. CHEST. Published online February 20, 2021.  doi:10.1016/j.chest.2021.02.019