Acid-fast bacilli staining for nonhealing ulcers: a case report of cutaneous Mycobacterium chelonae infection.

Cutaneous infections due to nontuberculous mycobacteria (NTM) are rare, and they can be challenging to treat, often requiring prolonged therapy with multiple antibiotics. Although recent literature challenges the idea of routine acid-fast bacilli (AFB) testing in diabetic foot infections, this report presents a case of Mycobacterium chelonae (M chelonae) infection in a patient with nonhealing ulceration. A 64-year-old female with no history of immunocompromise and no recent surgical history presented with a rapidly growing ulceration despite appropriate antibiotic therapy based on routine aerobic culture results. After AFB cultures were obtained, she was found to have NTM infection with M chelonae, and the ulceration was healed without recurrence after treatment for 4 months with linezolid and clarithromycin. This case highlights the potential inoculation of M chelonae, even in immunocompetent patients without known inoculation injury, and it highlights the value of AFB cultures in patients who do not progress with standard wound care therapies and routine aerobic cultures.