Other fungi of clinical interest !
- Fungi
Three loose chapters of the textbook: mycetoma of the foot, Talaromyces in AIDS in Asia, and microsporidia, now grouped with the fungi.
Updated 2026-11-01
What they are
Agents that do not fit the big fungal groups but still turn up in exams. Mycetoma is a syndrome caused by fungi or by filamentous bacteria; Talaromyces marneffei is an Asian dimorphic fungus tied to advanced HIV. Microsporidia were taught as protozoa for decades, but today they are classed with the fungi or as their closest relatives.
What they share
- They mainly affect people with immunosuppression (Talaromyces, microsporidia) or barefoot rural workers (mycetoma).
- Diagnosis rests on seeing the typical form: grains in the pus, yeasts with a central septum, or tiny spores with special stains.
- None spreads from person to person in ordinary clinical practice.
Microorganisms in this group
- Mycetoma agentsA chronic infection of skin and bone, nearly always of the foot, that enters through a thorn. It forms lumps that drain pus with grains.For completeness
- Talaromyces marneffeiA fungus from Southeast Asia that causes disseminated infection in people with advanced AIDS, with skin bumps dented in the centre.For completeness
- Microsporidia (Enterocytozoon, Encephalitozoon)Tiny parasites that live inside cells and cause chronic diarrhoea in AIDS. Once taught as protozoa, they are now grouped with the fungi.For completeness
Test yourself
Think of the answer, then tap the question to see it.
Which three findings define mycetoma clinically?
A firm painless swelling, draining sinus tracts, and grains in the discharge, which are colonies of the causative agent.
Why do some textbooks list microsporidia as protozoa?
They were classed that way for a long time; molecular studies placed them next to the fungi and they are grouped with them today, although many labs still handle them with the protozoa.
What history points to Talaromyces in a patient with AIDS and umbilicated skin lesions?
Having lived in or travelled to Southeast Asia, southern China or India.
Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Mycetoma Basics | Mycetoma | CDC (CDC, 2024); Talaromycosis (Penicilliosis) Basics | Talaromycosis | CDC (CDC, 2024); CDC - DPDx - Microsporidiosis (CDC, 2024).
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Representative model, for educational purposes only.