A 49-year-old male presented to the emergency room with a chest wound infection caused by Mycobacterium mageritense. Laboratory tests found low platelet and white blood cell counts. Culture of the chest wound grew acid-fast bacilli identified as M. mageritense. The patient was treated with a combination of doxycycline, moxifloxacin and imipenem antibiotics based on susceptibility testing, and follow up showed the treatment was successful in clearing the infection.