Courtesy of: Dr S Pina Oviedo (Mexico)
A 45 years-old man develop fever and respiratory distress, requiring admission to the hospital, intubation and mechanical ventilation. The patient serology was positive for HIV. Despite aggresive therapy, the patient died a couple of days later after admission. An autopsy was performed. A section of the lung showed the following findings (see image). Several other organs showed similar features.

1. What is the name of the organism? Cryptococcus neoformans var. neoformans
2. What is the stain?
Periodic acid-Schiff (PAS), which highlights the fungal organisms in a bright magenta color. GMS (Grocott methenamine stain) can also be used to highlight these organisms, which will appear black. These stains do not typically stain the capsule.
The cryptococcal capsule is stained with mucicarmine or Alcian blue. Capsule-deficient strains may be stained with Fontana-Masson, as Cryptococcus spp. produce melanin.
3. Who is the person attributed to have first described this infectious agent? C. neoformans was first isolated in 1894 by P. Sanfelice in Italy from peach juice, and by A. Busse and O. Buschke in Germany from the tibial lesion of a patient. Although both discoveries were accomplished in the same year, they were completely independent.
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