Mycobacterium flavescens Infection - An Unusual Case of Prosthetic Joint Infection.

Introduction: The onset of prosthetic joint infections (PJIs) is characterized by early onset defined as within 90 days of the procedure, delayed onset defined as within 3 to 12 months, and late onset defined as over 12 months. In only a scant number of case reports, Mycobacterium flavescens associated infections are typically found in sputum cultures and associated with various forms of penetrating joint traumas, particularly post-surgical interventions. Due to its rarity in presentation among cases of PJIs, we have presented a case of PJI caused by Mycobacterium flavescens.

Case presentation: We have, herein, reported a case of a 70-year-old male presenting with stabbing left knee pain over the past several months along with accompanying erythema and swelling with the presence of purulent discharge. Outpatient cultures have shown the growth of Mycobacterium flavescent; subsequently, the patient underwent a 2-stage revision arthroplasty and was treated with a three-drug regimen and implant 5 months later. Although being an atypical cause of PJIs, we emphasize the importance of considering NTM as a differential for immunocompromised patients, especially those with prior surgical intervention.

Discussion: Mycobacterium spp. related PJIs manifest clinical features similar to other bacteriacausing PJIs, such as warm, indurated edema at the surgical site resulting in wound dehiscence and joint effusion. Diagnosis of Mycobacterium spp. related PJIs includes history and physical examination findings, serum inflammatory markers, synovial fluid analysis, and culture. Concurrently with surgical interventions, utilization of antimicrobial agents provides additional control in Mycobacterium- related PJI. Mycobacterium flavescens should be included among other NTMs as a possible cause of PJIs.