PetriKey

Fungus

Talaromyces marneffei

Southeast Asian dimorphic fungus; fission yeast

tal-uh-ROH-mih-seez mar-NEF-eye

dimorphicendemicsoutheast-asiahivfission-yeastopportunistic

High-yield clue

Yeast dividing by fission (a transverse septum, not budding) plus red diffusible pigment in mold culture from a Southeast Asian HIV patient is the core study clue.

Overview

A thermally dimorphic fungus (formerly Penicillium marneffei) endemic to Southeast Asia and southern China that causes talaromycosis, an important opportunistic infection in advanced HIV. Classic geographic dimorphic-fungus teaching organism of Southeast Asia.

Classification

  • Thermally dimorphic fungus
  • Mold at 25C, yeast at 37C
  • Yeast divides by transverse binary fission (a central septum), not budding
  • Ascomycota (formerly Penicillium marneffei)
  • Endemic to Southeast Asia

Lab & identification clues

  • Intracellular fission yeast with a central septum vocabulary
  • Mold form produces a diffusible red pigment in agar vocabulary
  • Penicillus (brush-like) conidiophore in mold phase
  • Recovered from blood, marrow, or skin lesions in coursework

Associations

  • Talaromycosis in advanced HIV/low CD4 vocabulary
  • Endemic to Vietnam, Thailand, and southern China
  • Bamboo rats as environmental reservoir association
  • Umbilicated (molluscum-like) skin papules teaching vocabulary

Commonly confused with

  • Histoplasma capsulatum (small intracellular yeast)
  • Cryptococcus (encapsulated yeast)

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource