In mid-December,a woman with insulin-dependent diabetes who had been on prednisone fell and received an abrasion on the dorsal side of her right hand.She was placed on penicillin.By the end of January,the ulcer had not healed,and she was referred to a plastic surgeon.On January 30,a swab of the wound was cultured at 35°C on blood agar.On the same day,a smear was made for Gram staining.The Gram stain showed large (10 µm)cells.Brownish,waxy colonies grew on the blood agar.Slide cultures set up on February 1 and incubated at 25°C showed septate hyphae and single conidia.The most likely cause of the infection is a

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The large (10 µm) cells observed on the Gram stain and the presence of septate hyphae and single conidia on slide culture indicate a fungal infection. The brownish, waxy colonies on blood agar also suggest a dimorphic fungus, which can grow as both a yeast and a mold. This is a common characteristic of some fungal pathogens, such as Histoplasma and Coccidioides, that can cause chronic infections in immunocompromised individuals like this patient.

In Mid-December,a Woman with Insulin-Dependent Diabetes Who Had Been on Prednisone