An 80-year-old man with VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, and Somatic) autoimmune syndrome managed with multiple immunosuppressants presented with 3 months’ painful swelling of left knee, right ankle and right distal interphalangeal finger joints and fluctuating skin lesions. He did not report fever or weight loss. Examination revealed aforementioned tender joint effusions and multiple nodular skin lesions, with no central venous access devices. Blood cultures were obtained, and the aerobic bottle flagged positive after 4 days, with beaded Gram-positive bacilli seen on Gram Stain; colony growth on blood culture plates and from finger lesion biopsy and left knee and right ankle joint aspirate cultures stained acid-fast, confirmed by nucleic acid amplification testing as Mycobacterium chelonae. Empiric meropenem, clarithromycin and amikacin were commenced; broth microdilution-based susceptibility testing demonstrated susceptibility to amikacin and clarithromycin and doxycycline, resistance to cefoxitin and imipenem and ciprofloxacin, and intermediate susceptibility to linezolid. Although meropenem was switched with linezolid, acute kidney injury and anaemia led to cessation of amikacin and linezolid, and emergence of paradoxical cutaneous reactions required tapered prednisolone therapy. Prolonged therapy with doxycycline and clarithromycin is anticipated. This case highlights several challenges in managing disseminated Mycobacterium chelonae infections, including antimicrobial resistance and adverse reactions.
Rajkumar et al. (Sun,) studied this question.