Fecal and Sputum Microbiota and Treatment Response in Patients With Mycobacterium abscessus Pulmonary Disease

Background. The microbiota may provide biomarkers for clinical outcomes in chronic respiratory conditions, though its role in Mycobacterium abscessus pulmonary disease (PD) remains largely unknown. We aimed to identify microbial signatures in fecal and sputum microbiotas associated with treatment response in M abscessus PD. Methods. We prospectively enrolled patients undergoing antibiotic therapy, collecting fecal and sputum samples at baseline, 2 weeks, and 6 months. Using 16S rRNA amplicon sequencing, we analyzed microbiota diversity and composition in early treatment responders and nonresponders, classified by sputum culture results at 2 weeks. Results. Among 32 participants, 27 patients (median age, 66 years; 85.2% women; 48.1% with subspecies abscessus) were included for analysis. Fifteen patients (55.6%) achieved negative conversion at 2 weeks, sustained in 93.3% at 6 months. Responders showed signifcantly decreased fecal microbiota diversity at 2 weeks, unlike nonresponders (P = .029). Increased abundance of Eubacterium hallii in baseline fecal microbiota was indicative of unresponsiveness, whereas increased Enterococcus in feces at 2 weeks was linked with favorable response. In sputum, high baseline levels of Burkholderia-Caballeronia-Paraburkholderia and Porphyromonas, along with decreased Rothia at 2 weeks, were associated with good treatment response. Conclusions. In M abscessus PD, changes in microbial diversity and compositional signatures reflect treatment response.