A middle-aged man spent eight months cycling through treatments that did not work. Red patches on his left arm kept breaking open, oozing, and crusting over. Doctors gave him topical medications and oral antibiotics. The lesions came back. Three months before he reached a specialist center, surgeons cut out the damaged tissue and changed the dressings. The wound healed poorly, and new sores appeared on the fingers of his left hand. Another antibiotic did nothing.
The answer came from a question about his work. He had spent years in aquaculture, breeding and transporting fish and aquatic products. A skin biopsy showed granulomatous inflammation and acid-fast bacilli, and genetic sequencing named the culprit: Mycobacterium marinum, an environmental bacterium that lives in fresh and salt water and infects people through small breaks in the skin.
