Abstract: A 65-year-old male patient presented with a rash on his right middle finger for 50 days and a rash with itching and pain on his right upper limb for 20 days. Histopathological examination was consistent with an infectious granuloma. Metagenomic next-generation sequencing (mNGS) of the right forearm skin lesion tissue indicated the presence of Mycobacterium species. The stain of skin purulent secretion was positive for acid fast staining, and the strain was identified as Mycobacterium marinum by PCR sequencing. After the treatment of rifampicin and ethambutol, the rashes of the patient subsided after 4 months and there was no recurrence after 1 year follow up.

Key words: Mycobacterium marinum, shrimp puncture, metagenomic next-generation sequencing