A new twist on an old trick: the use of MAAB soaks to treat angioinvasive Fusarium

Jennifer Schneider; Sarah Mitchell; Philip Antiporta; Therese Duane

Fusarium spp. is an opportunistic fungus with variable susceptibility to antifungals that can cause localized skin and soft tissue infection and potentially spread hematogenously with high mortality in the immunocompromised. In this paper we describe the successful treatment of angioinvasive Fusarium with topical mafenide acetate-Amphotericin B (MAAB) via irrigating negative pressure wound therapy (NPWT) device. Our patient is a 59 year-old wheelchair bound African American male with history of controlled diabetes, hypertension, atrial fibrillation, and new diagnosis of COVID-19 presenting with generalized weakness and diffuse, coalescing bullae over bilateral lower extremities. Duplex scan showed deep venous thrombosis of bilateral femoral and popliteal veins suggesting venous stasis potentiating wound formation. Despite local wound care, wound severity progressed to circumferential skin sloughing with underlying woody appearance of the dermis to the level of the knees. He underwent multiple operative debridements with findings of extensive full thickness skin/soft tissue necrosis and thrombosed superficial veins. Cultures isolated various bacterial species treated with systemic antibiotics and Fusarium spp. Due to extensive and progressive soft tissue injury we performed bilateral above knee guillotine amputations. Pathology revealed angioinvasive fusarium and fungal blood cultures were negative suggesting no hematogenous spread. Susceptibility testing showed resistance to itraconazole, posaconazole, and voriconazole and he was started on Amphotericin B. Unfortunately, after two days of therapy he developed an acute kidney injury and was transitioned to intravenous isavuconazonium, to which his Fusarium was later found to be resistant. His wounds continued to grow Fusarium after repeat debridements so we initiated MAAB soaks via an irrigating NPWT device to ensure continuous tissue contact. After a month, biopsy culture showed no Fusarium growth. Soaks continued for an additional two months with clinical resolution of Fusarium and no systemic signs of infection. In conclusion, extensive cutaneous Fusarium infection in an immunocompetent host is a rare clinical disease and we hypothesize phlegmasia secondary to COVID 19 had an important role in this patient. We found that early surgical intervention and wound care using MAAB soaks with an irrigating NPWT device resulted in resolution when systemic antifungals were not an option.

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