Mycobacterium mucogenicum septic arthritis of the knee: A case report

Abstract

Background: Mycobacterium mucogenicum is a non-tuberculous mycobacterium that is found ubiquitously in the environment. This article is the first report of septic arthritis caused by M. mucogenicum. Case report: A 44-year-old female healthcare worker presented with atraumatic left knee pain and systemic features suggestive of septic arthritis in the context of recent left knee trauma and arthroscopic debridement. Over the course of five months, she underwent four arthroscopic or open procedures and received eight different antibiotics in pursuit of a definitive diagnosis and curative treatment. Intraoperative cultures grew multiple organisms, including methicillin resistant Staphylococcus aureus and M. mucogenicum. Follow-up at three months revealed complete resolution of symptoms and good mobility of the joint. Conclusion: As an atypical organism that is difficult to detect, good culture facilities and a high level of suspicion is required to diagnose Mycobacterium mucogenicum infection. The delay in antimicrobial sensitivity availability necessitates empirical antibiotics, and the ability of the pathogen to form biofilms necessitates aggressive synovectomy for local control. Identifying contributing risk factors such as immunosuppressive therapy or an underlying condition is crucial for achieving a cure. The need for synergistic antibiotic and orthopaedic treatment highlights the need for a multidisciplinary approach involving both specialized Infectious Diseases and Orthopaedic teams to treat this hardy pathogen.

Keywords

• Mycobacterium mucogenicum
• Rapidly growing mycobacteria
• Septic arthritis
• Non-tuberculous mycobacteria