Acid-Fast Bacilli Staining Reveals Mycobacterium chelonae in a Nonhealing Ulcer

Summary: A case report in WOUNDS documents a rare instance of Mycobacterium chelonae infection in a chronic foot ulcer that failed to heal despite appropriate standard care. Acid-fast bacilli (AFB) staining and cultures identified the pathogen in an immunocompetent patient, leading to successful treatment with a four-month course of linezolid and clarithromycin, alongside antimicrobial dressings—resulting in wound closure after 10 weeks.

Case Highlights:

• The patient, a 64-year-old woman with type 2 diabetes and managed peripheral arterial disease, had an ulcer unresponsive to multiple antibacterial regimens and debridement.
• Routine cultures were negative, but a follow-up punch biopsy with AFB staining revealed the presence of M. chelonae.
• The tailored antibiotic combination, coupled with silver alginate dressings, achieved healing within ten weeks.

Clinical Implications: While AFB infections are uncommon in chronic ulcers, this case underscores the importance of considering alternative pathogens when wounds are nonhealing. Clinicians should consider biopsy and AFB testing after 4–6 weeks of failed conventional care.

🔗 Read the full case report on WOUNDS

Keywords: Stephanie Behme, Shiwei Zhou, Andrew Brown, Gary Rothenberg, Mycobacterium chelonae, acid-fast bacilli, AFB culture, chronic ulcer, linezolid and clarithromycin