Mycobacterium abscessus Otitis Externa and Otitis Media Successfully Treated With Surgical Drainage: A Case Report

Nontuberculous mycobacteria (NTM) are environmental organisms that most commonly cause pulmonary disease; infections involving the external and middle ear are rare and can be diagnostically challenging. We report a case of chronic otitis externa and otitis media caused by Mycobacterium abscessus in a woman in her 30s. She presented to our department with an 18-month history of recurrent left aural fullness and otorrhea that had not responded to treatment at other facilities. At the referring hospital, she had marked swelling of the external auditory canal (EAC) with exposed bone, and nucleic acid amplification tests for Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare were negative. On presentation to our department, examination revealed marked edema and erythema of the EAC with purulent otorrhea. Despite repeated aural toilet and topical treatment, inflammation persisted. The tympanic membrane was thickened and perforated in the anteroinferior quadrant, and granulation-like tissue filled the middle ear. CT demonstrated soft-tissue opacification extending from the middle ear to the mastoid air cells without bony destruction. Because of persistent disease, mycobacterial culture of the otorrhea was performed at our department and identified M. abscessus. Oral levofloxacin and clarithromycin based on susceptibility testing provided limited improvement. The patient was therefore treated with IV imipenem and amikacin in addition to ongoing oral levofloxacin and clarithromycin, followed by mastoidectomy and tympanoplasty for drainage and source control. She remained free of recurrent otitis externa or otitis media, and CT one year after surgery showed complete resolution of the EAC thickening and middle-ear opacification. In refractory chronic otitis externa or media, particularly when routine testing is unrevealing, mycobacterial culture should be considered even when nucleic acid amplification tests performed at a referring institution are negative. Combined antimicrobial therapy and surgical drainage may achieve effective infection control in extensive or longstanding M. abscessus otologic infection.