Abstract: Objective: To explore the clinical characteristics, diagnosis and treatment methods of cutaneous NTM (nontuberculous mycobacteria) infection, and to improve the understanding and diagnostic level of cutaneous NTM infection. Methods: From April 2022 to August 2024, 57 patients with suspected cutaneous NTM infection were collected from the Dermatology Outpatient Department of Xijing Hospital. The results of culture method, acid-fast staining, and nucleic acid sequencing, as well as the treatment and prognosis, were statistically analyzed. Results: Thirty four cases were finally diagnosed with cutaneous NTM infection, including 18 males (52.94%) and 16 females (47.06%). The onset age ranged from 14 to 81 years old, with an average age of (51.79±15.96) years old, mainly in the age group over 40 years old. Patients with disease duration ≥6 months accounted for the highest proportion（72.22%）. Half of the patients had trauma-related onset causes, mainly fishbone stabbing. There were 22 cases (64.71%) of multiple skin lesions, which was higher than 12 cases (35.29%) of single skin lesions. The main clinical manifestation was plaques, accounting for 44.12%; the main affected site was the hand, accounting for 58.82%. The positivity rate of nucleic acid sequencing identification was the highest, which was 85.29%, followed by acid-fast staining of 70.59%, and that of tissue culture was the lowest, which was 29.41%. In terms of species identification results, the infection rate of Mycobacterium marinum was the highest, with 21 cases (61.76%). There was 2 case treated by surgical resection, 1 case with traditional Chinese medicine treatment and 31 cases treated with antibiotics. 28 cases (82.35%) were clinically cured, 6 cases (17.65%) improved, the total effective rate was 100%, and 4 cases (11.76%) relapsed. Conclusion: Cutaneous NTM infection is mainly caused by Mycobacterium marinum infection, which is more common in middle-aged and elderly people. The manifestations of skin lesions are complex and diverse, and comprehensive consideration should be given in clinical diagnosis and treatment.

Key words: nontuberculous mycobacteria, acid-fast staining, nucleic acid sequencing