Pathogen genotypes and host phenotypes of Mycobacterium abscessus pulmonary disease in Taiwan

Mycobacterium abscessus (Mabs) pulmonary disease (Mabs-PD) is difficult to treat, particularly in subspecies abscessus (Mabs-a), usually harboring macrolide-resistant sequevars, unlike subspecies massiliense (Mabs-m). The relationship between Mabs genetic variants and clinical features remains largely unexplored.

In this retrospective cohort study, patients with Mabs-PD and Mabs extrapulmonary disease (Mabs-ED), identified during 2016-2018, were observed for severe or progressive Mabs-PD, indicated by antibiotic needs or increased lung lesions. DNA of Mabs isolates was sequenced to determine subspecies and evaluate macrolide-resistance genetic variants (rrl mutations or functional erm(41) with T28 sequevar).

The Mabs-PD group (n = 77) was older and thinner than the Mabs-ED group (n = 20). In Mabs-PD, macrolide-resistance genetic variants were detected in 84.6 % of Mabs-a (n = 42) and 9.4 % of Mabs-m (n = 35) isolates (p < 0.001). Cavitary disease (n = 10) and non-cavitary bilateral disease (n = 45) were associated with an increased risk of severe or progressive Mabs-PD compared to non-cavitary unilateral disease (n = 22) (adjusted odds ratio 13.039 [95 % CI 1.239-137.172], p = 0.032; and 4.875 [0.755-31.502], p = 0.096, respectively). Patients with cavitary disease or non-cavitary bilateral disease were more likely to harbor Mabs-m isolates compared to those with non-cavitary unilateral disease (50.0 % and 57.8 % vs. 18.2 %, p = 0.008). Bilateral disease (n = 54, with 9 cavitary disease included) was inversely associated with macrolide-resistance genetic variants, a finding consistent across subgroup analyses, with an adjusted odds ratio of 0.187 (95 % CI [0.054-0.646], p = 0.008).

Mabs-PD patients with cavitary or bilateral disease, potentially requiring treatment initiation, had a lower risk of harboring macrolide-resistant Mabs, emphasizing the importance of phenotype-specific investigations to enhance clinical decision-making.