Clinical features and treatment outcomes of Mycobacterium colombiense pulmonary disease: a retrospective study

BACKGROUND: Mycobacterium colombiense (M. col), a rare member of the Mycobacterium avium complex (MAC), primarily infects immunocompromised individuals and often causes disseminated disease with high mortality. Clinical understanding of its manifestations and outcomes remains limited. METHODS: We conducted a retrospective study at a single tertiary center in Sichuan, China, reviewing records of patients diagnosed with nontuberculous mycobacterial pulmonary disease (NTM-PD) from 2009 to 2024. Data collected included demographics, clinical symptoms, imaging findings, laboratory results, treatment regimens, and outcomes. Comparative analyses were performed between patients with M. col pulmonary infection and those with other MAC pulmonary infections. RESULTS: Among 299 NTM-PD cases, 134 (44.8%) were diagnosed with MAC pulmonary infection, including 11 (3.7%) confirmed as M. col pulmonary infection. Compared to other MAC infections, patients with M. col exhibited higher rates of disseminated disease (36.4% vs. 7.3%, p < 0.05), fever (45.5%), dyspnea (72.7%), and concurrent infections (72.7% vs. 37.4%, p < 0.05), along with elevated eosinophil counts and lower hemoglobin levels. Imaging findings and antibiotic susceptibility showed no significant differences compared to other MAC infections. Treatment outcomes were comparable between the two groups when guideline-based regimens were followed. CONCLUSION: M. col demonstrates a predilection for extrapulmonary dissemination and polymicrobial infections, exhibiting distinct clinical and laboratory features compared to other MAC subspecies, but responds similarly to standard MAC antibiotic therapy. CLINICAL TRIAL NUMBER: Not applicable.