Non-Tuberculous Mycobacterial Infections of the Skin and Soft Tissue in a Chinese Population: A Retrospective Analysis of 15 Cases.

Background: Non-tuberculous mycobacteria (NTM) skin and soft tissue infections (SSTIs) are increasingly recognized but underdiagnosed in China.

Methods: This retrospective study analyzed 15 confirmed cases of NTM SSTIs treated at a southern Chinese hospital from 2012 to 2022. Clinical data, including demographics, clinical presentations, comorbidities, diagnostic methods, treatment regimens, and outcomes, were collected and analyzed. Diagnostic efficacy of conventional culture and metagenomic next-generation sequencing (mNGS) was compared.

Results: The median age of patients was 57 years, and 66.7% were farmers. Pathogens identified included Mycobacterium abscessus (20.0%), M. marinum (13.3%), and rapidly growing mycobacteria (13.3%). Immunocompromised states, such as anti-interferon-gamma autoantibody positivity, were present in 40.0%. mNGS demonstrated superior diagnostic performance, achieving a detection rate of 86.7% (13/15 cases), compared to 26.7% for culture. Treatment regimens, including clarithromycin, rifampin, ethambutol, and moxifloxacin, lasted 1-24 months. Outcomes showed cure in 8 patients (53.3%), improvement in 6 (40.0%), and 1 lost to follow-up.

Conclusion: NTM SSTIs present significant diagnostic and therapeutic challenges, with clinical variability and frequent association with immunocompromised states. M. abscessus, M. marinum, and M. avium were the predominant pathogens. mNGS improves detection but still should complement culture. Precise pathogen identification and tailored therapy are essential for achieving optimal outcomes, and further studies are needed to refine diagnostics and treatment strategies.