Rare Case of Non-tuberculous Mycobacterial Infection following Repair of Pectoralis Major Avulsion: Case Report and Review of Literature.

Introduction: Non-tuberculous mycobacteria (NTM) infections of the musculoskeletal system are commonly missed due to their rarity and the absence of systemic symptoms. Here, we present a rare case of NTM infection following repair of an avulsed pectoralis major tendon in an immunocompetent host managed by a multi-disciplinary team specializing in musculoskeletal infections. Case Report: A 23-year-old male patient presented with discharging sinus in the right axilla for 6 months. He sustained the right pectoralis major muscle avulsion following an accident which was surgically repaired using FiberWire® and endo buttons. He developed a discharging sinus 4-month post-surgery. He presented with persistent infection in spite of empirical antibiotics elsewhere. Radiographs and MRI sonogram showed intra-medullar endo buttons in the proximal humerus with marginal pus collection in the axillary region with minimal medial extension into pectoralis major and minor muscles along the superior aspect. A detailed plan was made with inputs from a multidisciplinary bone infection team. Wound was radically debrided, implants and sutures removed, humerus scraped, and tissues sent for microbiology and histopathology. Extended incubation of deep tissue culture as suggested by ID specialists grew Rapidly growing mycobacteria, a type of NTM 3 weeks after surgery. Patient was started on intravenous amikacin along with oral clarithromycin and linezolid based on antibiotic susceptibility. Wound discharge persisted for almost 5-week post-surgery and stopped 2 weeks after initiation of appropriate antibiotics. Amikacin was given for 1 month and oral antibiotics were continued for 6 months. The pectoralis major function was unaffected after surgery and patient returned to normal activities 3 months after debridement. Patient has an infection free follow-up of 4 years. Conclusion: This case outlines the importance of having a high degree of suspicion for the diagnosing orthopedic NTM infections. In addition, it showcases the advantages of having good communication between surgeons, infectious disease specialist, and microbiologist for achieving good functional outcomes.