Fulminant necrotizing fasciitis caused by zygomycetes

To the Editor, Necrotizing fasciitis (NF) is a progressive, rapidly spreading, inflammatory infection located in the deep fascia, with secondary necrosis of the subcutaneous tissues. Most cases are bacterial in origin, caused by mixed aerobic and anaerobic organisms (70%), anaerobes (20%) and aerobes (10%). It is commonly associated with severe systemic toxicity and high mortality in the range of 25–70%. Opportunistic fungal infections are an important cause of cutaneous necrotizing infections in immunocompromised patients, and zygomycosis in the debilitated patient is the most acute and fulminant fungal infection known. Percutaneous risks for developing infection with these fungi are well described, and here in, we present a case of fulminant NF caused by zygomycetes following an intramuscular injection. A 23-year-old female presented in casualty with high-grade fever and a deep ulcer involving the right gluteal region, extending to her thigh and lower back. She gave a history of an unknown intramuscular injection 1 month back. Two weeks later, she had developed a painful ulcer at the site of the injection. She had received some local treatment (details unknown) from a private medical practitioner, but as the lesion started extending, she was referred to our hospital. On examination, patient was febrile, toxic and had a large soft tissue infection spreading along the fascial planes producing necrosis of overlying skin. The area involved included the right gluteal region, thigh and lower back. (Fig. 1A) A clinical diagnosis of NF was established, and an emergency surgical debridement was carried out, and broad-spectrum antibiotics active against both aerobic and anaerobic bacteria ware started. Laboratory studies revealed hemoglobin of 3 gm/ dl, total white cell count of 15,000/mm with raised neutrophils. Serum biochemistry showed deranged renal function test with urea and creatinine 80 and 3 mg/dl, respectively, urine analysis showed proteinuria. Bacterial culture of excised tissue showed growth of Proteus mirabilis, susceptible to third generation cephalosporins and aminoglycosides. In spite of aggressive management, the patient continued to deteriorate. The diagnosis was reviewed, and considering a possibility of cutaneous mycosis, surgically excised tissues were sent for mycological evaluation. KOH wet mount showed broad, nonseptate hyphae (Fig. 1B), and in sections of resected tissue stained by hematoxylin and eosin (Fig. 1C), periodic acid-Schiff (Fig. 1D) and Grocott methenamine silver stains broad hyphae of varying diameters with minimal septation and irregular branching were seen. Fungal culture on Sabouraud’s dextrose agar showed no growth. Amphotericin-B could not be started because patient was in renal failure, and the clinical condition of patient kept on deteriorating despite surgical debridement and intensive medical management. The patient and her family denied further treatment and took leave against medical advice. Zygomycetes class of fungi includes three orders that are Mucorales, Mortierellales and Entomophthorales. The majority of human illness is caused by the Mucorales. Zygomycosis is an emerging cause of NF, and in a recent study, zygomycosis was responsible for 31.03% cases of NF. Early diagnosis is the corner stone of successful treatment of zygomycosis. Treatment of zygomycosis requires several simultaneous approaches: surgical intervention, antifungal therapy and correction of the underlying predisposing condition. Surgical debridement of grossly necrotic tissue is always required; in addition, antifungal agents such as Amphotericin B/posaconazole should be coadministered. Hyperbaric oxygen, Granulocyle colony stimulating factor and interferong might give some benefit, as adjunctive treatment and their role require further evaluation. Continued expansion of the wound despite broadspectrum antibiotic therapy, failure to isolate bacterial organisms and demonstration of ribbon like, aseptate hyphae in tissue section are some of features that are helpful in the early diagnosis of NF of fungal etiology. Rapid progression and unacceptably high mortality