Metagenomic and genomic characterization of extrapulmonary Mycobacterium abscessus infections: a comparative cohort study.

INTRODUCTION: The incidence of Mycobacterium abscessus complex (MABC) infections is rising, becoming a major pathogen of nontuberculous mycobacteria responsible for pulmonary disease (PD) and extrapulmonary disease (ED). However, studies on the clinical characteristics of MABC-ED remain limited. METHODS: A 7-year retrospective analysis was conducted on MABC-ED cases at Zhongshan Hospital in Shanghai, China. We analyzed predisposing factors, clinical features, metagenomic sequencing (MS) results, drug susceptibility testing (DST), and genomic characteristics of MABC-ED patients, comparing the data with those of PD cases. RESULTS: Among 17 MABC-ED patients, 15 had predisposing risk factors and underlying conditions, with 2 of 3 patients with rheumatic disease showing poor prognosis. The diagnostic performance of metagenomic sequencing for MABC-ED was comparable to that for MABC-PD. However, MABC-ED samples exhibited distinct microbiome features and a more diverse mycobacterial community structure compared to PD. Resistance rates among extrapulmonary MABC isolates were observed as follows: 0% (amikacin), 20% (macrolides), 30% (linezolid), and 40% (cefoxitin). One case showed paradoxical results between erm (41) T28 sequevar and susceptibility phenotype. Genomic analysis revealed no specific dominant circulating clones (DCC) for MABC-ED isolates. CONCLUSION: MABC-ED patients commonly present with risk factors and underlying diseases. Metagenomic sequencing diagnosis of MABC-ED poses challenges, and DST and whole genome sequencing data indicate diversity among MABC-ED isolates. Our study provides detailed data on MABC-ED, contributing to a better understanding of its disease characteristics.