Fulminant post-traumatic mucormycosis caused by Mucor circinelloides in an immunocompetent host: a case report

Necrotizing soft tissue infections (NSTIs) are surgical emergencies. While bacteria are the most common cause, invasive fungal infections like mucormycosis must be considered following severe trauma. Mucor circinelloides is an infrequent cause of fulminant infection in immunocompetent hosts compared to other Mucorales. This report details a challenging case of post-traumatic M. circinelloides mucormycosis in an otherwise healthy 55-year-old male. Following a severe crush injury to the right lower leg, the patient developed rapidly progressing tissue necrosis and septic shock despite standard management. Key clinical signs included disproportionate pain, extensive black eschar, and vascular thrombosis. Direct microscopy of debrided tissue revealed ribbon-like, pauciseptate hyphae, prompting a diagnosis of mucormycosis. Culture and whole-genome sequencing (WGS) identified the pathogen as M. circinelloides . Despite standard-dose liposomal amphotericin B and repeated debridement, the infection ultimately required a life-saving transtibial amputation; the patient subsequently recovered. This case adds to the evidence that M. circinelloides can cause devastating disease in healthy individuals. A triad of urgent microscopy, aggressive surgical debridement, and prompt antifungal therapy is critical. Clinicians must maintain a high index of suspicion for angioinvasive fungi when tissue necrosis is disproportionate to the injury, regardless of the patient’s immune status. Not applicable.