Mucor indicus necrotizing fasciitis
Authors: Mata‐Essayag Sofia , Magaldi Sylvia , De Capriles Claudia Hartung , Henao Libia , Garrido Liselotte , Pacillo Vito 
Published: March 2003

An 82‐year‐old otherwise healthy woman was admitted to the Internal Medicine Department of Clínica Atías, Caracas, Venezuela, with advanced necrotizing fasciitis with exposure of muscle and bones on the left knee. According to the patient, the clinical manifestation started 8 days earlier after applying several warm compresses made of cosmetic clay with mashed onion on her aching knee. Erythematous swelling with ulceration followed. She had been taking tobramycin (80 mg every 12 h). By the time the patient was admitted, she was severely ill, with fever and necrosis of the skin, subcutaneous fat, superficial fascia, and exposure of the muscles and bone of the affected area. Examination under a microscope of necrotic material from the lesion showed broad, coenocytic hyphae with right angle branching, characteristic of Zygomycetes (Fig. 1). Amphotericin B was administered. Subsequently, due to amphotericin B intolerance and the rapidly deteriorating general condition of the patient, immediate amputation of the extremity and empirical treatment with fluconazole was initiated. Treatment with this drug was continued for 3 months with a favorable response, despite the fact that the diameter of the inhibition zone to fluconazole by the ‘‘in vitro’' susceptibility test was only 12 mm. No recurrence of the disease was observed during 1 year of follow‐up. The fungus isolated from the lesion was identified as Mucor indicus.

Coenocytic hyphae with right angle branching in the necrotic tissue. KOH and blue–black Parker ink (× 40)

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Mucor indicus was isolated from both the patient's skin samples and the cosmetic clay. Microscopic examination of the cosmetic clay revealed the same hyphae as in the patient samples. On beerwort agar at 40 °C it grew slightly floccose, elevated at the center with a disk‐shaped diffuse border, white, nonsporulating, and with scarce aerial mycelium (4.5 cm in 7 days). On beerwort agar at 28 °C, the entire Petri dish was covered with abundant aerial mycelium, fluffy, pale mouse gray, buff on the reverse, sporulating abundantly. The color intensified if left to stand. On Sablac agar at 37 °C it grew 2.25 cm/day (Sablac agar formula: peptone, 10 g; glucose, 20 g; agar, 12 g; cows' milk, 200 mL; tap water, 800 mL; Borelli D. Contribución al estudio de tinea capitis en Venezuela. Arch Venez Med Trop Parasitol Med 1962; 4 (2): 46). In thermophilic studies, optimal growth and abundant sporulation were attained between 25 and 35 °C, whereas only growth was observed at 40 °C on beerwort agar. On Sablac agar, the fungus grew with sporulation up to 40 °C. At 27 °C on malt extract agar, it developed sporangiophores (repeatedly branched sympodially, with or without yellowish‐brown contents), sporangia (initially golden yellow, later with a brownish aspect, between 14.4 and 34.5 μm), columellae (subglobose), and sporangiospores (subglobose to cylindrical–ellipsoidal, 3–4.5 μm) (Fig. 2). Identification was made according to descriptions given by Schipper (Schipper MAA. Studies in mycology no. 17 by Schipper Centraalbureau voor Schimmelcultures Baarn. Inst R Neth Acad Sci Lett 1978; 17: 8–10). A sensitivity test was performed by the ‘‘in vitro’' well diffusion method (Magaldi S, Mata S, Camero T et al. Determinación de la sensibilidad antifúngica en agentes de cromomicosis mediante la técnica de los pozos de difusión. Antibiót Infecc 1999; 7 (1): 17–20). The diameters of the inhibition zone for the different fungal agents were: ketoconazole, 36 mm; terbinafine, 34 mm; econazole, 30 mm; bifonazole, 26 mm; tioconazole, 25 mm; itraconazole, 22 mm; amphotericin B, 22 mm; fluconazole, 12 mm (Fig. 3).

Mucor indicus sporangiophore and sporangiospores (pure culture on malt extract agar at 27 °C; bar, 125 μm)

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Mucor indicus. Well diffusion susceptibility test: a, fluconazole (12 mm); b, terbinafine (34 mm); c, itraconazole (22 mm); d, ketoconazole (36 mm)

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