(0325) Phage Therapy for Treatment of Mycobacterium Abscessus Mastoiditis

Introduction: Atypical mycobacterial mastoiditis is rare, but its incidence appears to be increasing. With this comes a need for expanded treatment options to achieve resolution of this difficult-to-treat infection. Phage therapy has been successful in treating challenging infections given the ability to specifically engineer phages to infect offending bacteria. We report on the use of phage therapy for the treatment of mycobacterium abscessus mastoiditis in two patients.

Methods: Case 1: A 39-year-old female with long-standing left-sided mycobacterium abscessus mastoiditis was treated with four prior tympanomastoidectomies and multiple rounds of long-term antibiotic therapy. She unfortunately continued to have left-sided otorrhea and hearing loss. Given her desire to avoid subtotal petrousectomy and ear canal closure, she elected to proceed with phage therapy.

Case 2: An 8-year-old female with left-sided mycobacterium abscessus mastoiditis was treated with two prior mastoidectomies and an extended course of IV antibiotics. On postoperative follow up, she continued to have signs of infection on otoscopy and imaging. Discussion of next steps included canal wall down mastoidectomy and ear canal closure versus initiation of phage therapy.

Results: Case 1: Following revision tympanomastoidectomy for debridement and placement of a transcutaneous port, phage therapy was initiated via topical and IV routes. With 7 months of treatment, the patient has had improvement in her symptoms. Treatment is ongoing.

Case 2: Initiation of treatment is pending development of patient-specific phages. Once the phages are available, the patient will undergo debridement of the mastoid, middle ear, and external ear canal with placement of conduit into the mastoid to allow for topical phage administration.

Conclusions: Phage therapy offers safe and highly individualized treatment of infections. Given the chronic and challenging nature of atypical myocobacterial mastoiditis, phage therapy offers a specialized treatment approach for patients with persistent infection despite appropriate surgical and antibiotic management.