Introduction
Mycobacterium chelonae is classified as a rapidly growing nontuberculous mycobacterium (NTM) that is ubiquitous in nature(2). It primarily causes disseminated cutaneous disease in immunocompromised individuals such as those on long term monoclonal antibodies, immunosuppressants, or corticosteroids(1). M. chelonae is a rare cause of chronic infection and its multidrug resistance has proven to be challenging to treat(3). In this case we report the clinical course of a woman with chronic soft tissue infection.

Case Presentation
A 52-year-old female with a prior history of steroid dependent COPD, asthma, chronic anemia, uncontrolled hypertension, cellulitis, and severe osteoporosis presented to the emergency department with swelling and redness of her right arm. She had a history of recurrent hospitalizations where she was previously treated for lower extremity cellulitis and edema. Her husband advertised that present swelling had started suddenly and had been quickly increasing in size. The increase had caused the patient significant tenderness in the area. Her vitals were BP: 165/81, pulse: 98.1, resp 20, O2: 97%, WBC: 8.7. Physical exam demonstrated an erythematous upper, right arm that’s warm to touch with 1+ edema.

At first there were multiple differentials because of the constellation of symptoms. The erythema could be caused by cellulitis, fungal infection, or a DVT. A US doppler of the right upper extremity showed no evidence of thrombosis. Cultures were collected and the patient was started on IV vancomycin and Zosyn.

Working Diagnosis
After seventeen days the patient was discharged. The erythema had developed into subcutaneous nodules that had only minimally improved with steroids and antibiotic treatment. The patient was discharged on doxycycline with appointments to see dermatology and rheumatology. One month after presentation the patient’s nodules were drained and a biopsy was conducted. AFB demonstrated Mycobacterium and PCR concurred that she had M. chelonae.

Outcome
The patient was put on a regimen of IV tobramycin, oral clarithromycin, and levofloxacin. This regimen would be continued for the next four months. The cutaneous lesions seemed to only improve with the tobramycin, however, this decreased her GFR. Her cutaneous lesions have persisted, and preliminary stains demonstrate many acid-fast bacilli.

References and Resources

1. Griffith, DE,Rapidly growing mycobacterial infections: Mycobacteria abscessus, chelonae, and fortuitum, In: UpToDate, Post, TW (Ed), UpToDate, Waltham, MA. (Accessed on July 5, 2023)
2. Akram SM, Rathish B, Saleh D. Mycobacterium chelonae Infection. 2023 Feb 25. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 28613557.
3. Hrvatin Stančič B, Žgavec B, Bergant Suhodolčan A. Mycobacterium chelonae infection in an immunocompromised patient presenting as multiple papulonodules on the leg. Acta Dermatovenerol Alp Pannonica Adriat. 2022 Mar;31(Suppl):S21-S24. PMID: 35339138.