1. Presented by Pia Sengupta and reviewed by Nikki Parrish, Ph.D.

An adult patient has a past medical history of Crohn’s disease and chronic orthopedic infection of their left wrist following an MVC, lasting several months. They have undergone multiple debridements, resections, and synovectomy without resolution. The patient admitted to rinsing their wound using the well water at home. Cultures over the course of the patient’s relapsing clinical course revealed numerous organisms, including Enterococcus faecalis, Candida parapsilosis, Staphylococcus haemolyticus, Synecphalastrum monosporum, Staphylococccus epidermidis, Mycobacterium abscessus, and Malassezia pachydermatis.

Ultimately, the infectious disease team determined the most likely organism for this patient’s prolonged and resistant presentation was an acid-fast bacillus, which grew in culture in under 7days, indicating a rapidly growing species of mycobacteria. Which of the following organisms was implicated by the clinicians as the cause of the patient’s prolonged infection?