Cutaneous mucormycosis confirmed using a Mucorales-specific monoclonal antibody: a case study

Mucormycosis is a highly aggressive and destructive angio-invasive infection caused by fungi of the order Mucorales. Diagnosis currently relies on lengthy and insensitive culture of biopsy specimens, as well as time-consuming histopathological examination of tissue samples, which lacks specificity.

This case study describes an unusual presentation of cutaneous mucormycosis in an immunocompetent 49-year-old man following a traumatic farming injury to the hand. Despite appearing clinically well and having wounds that looked macroscopically clean after repeated debridement, the patient had a persistent infection caused by the Mucorales fungus, Lichtheimia ramosa. Diagnosis was delayed due to low clinical suspicion and routine homogenisation of biopsy samples, which reduced the sensitivity of conventional fungal culture and microscopy. Early surgical debridement combined with antifungal therapy was essential; however, treatment was complicated by amphotericin B-associated nephrotoxicity, necessitating a switch to posaconazole. The patient ultimately achieved wound healing with preserved hand function.

The case demonstrates key challenges in diagnosing cutaneous mucormycosis, particularly in immunocompetent patients with environmentally contaminated wounds. The study highlights the need for improved awareness, optimal tissue handling, and more specific diagnostics for mucormycosis. We demonstrate the successful clinical use of a Mucorales-specific monoclonal antibody (mAb TG11), both as an immunohistochemistry stain and within a rapid lateral-flow device (LFD), to detect signature molecules of Mucorales infection in homogenised tissue samples, thereby improving the accuracy and speed of detection.