A HIV positive female presents with an indurated ulcer over the tongue. Laboratory findings show growth in cornmeal agar at 20 degree celcius, microscopy showing hyphae and growth in human serum at 37 degree celcius show budding yeasts. The probable cause is -

Oral Thrush d/t candida are common in HIV patients. (CD4+ cell count < 300) Oral Thrush presents as discrete & coagulant adherent white plaques on the oral & pharyngeal mucosa particularly in the mouth and on the tongue. All candida species pathogenic for humans grow rapidly at 25° to 37° on simple media as oval budding cells. In a special culture media and in tissue hyphae or elongated branching structures pseudohyphae are formed. All the other fungi Histoplasma Blastomycosis Coccidioidomycosis do not cause oral thrush, neither do they form Pseudohyphae on culture media. In HIV +ve patient the diagnosis of oral thrush is made by discet examination of a scraping for pseudohyphal elements. Culturing is of NO diagnostic value as patient may be +ve cultures for landid in absence of thrush.