[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Other fungi of clinical interest](https://durgical.com/en/microbiology/groups/other-fungi-of-clinical-interest/) › Mycetoma agents [Microbiology](https://durgical.com/en/microbiology/) · [Other fungi of clinical interest](https://durgical.com/en/microbiology/groups/other-fungi-of-clinical-interest/) # Mycetoma agents - Fungus - For completeness A chronic infection of skin and bone, nearly always of the foot, that enters through a thorn. It forms lumps that drain pus with grains. Updated 2026-11-01 Also called: Madura foot, maduromycosis ## Key points - Triad: painless swelling, sinuses and grains. - First find out whether it is a fungus (eumycetoma) or a bacterium (actinomycetoma): it changes the whole treatment. - Black grains: think Madurella (eumycetoma); red grains: Actinomadura pelletieri (actinomycetoma). - WHO lists it among the neglected tropical diseases. ## At a glance **Family** Eumycetoma: e.g. Madurella mycetomatis; actinomycetoma: Nocardia, Actinomadura, Streptomyces **Type** A syndrome, not one species: more than 70 agents, fungi (eumycetoma) or aerobic actinomycetes (actinomycetoma) **Stain** Grains: Gram (fine Gram-positive filaments in actinomycetoma), PAS or Grocott (broad hyphae in eumycetoma) **Size** Grains visible to the naked eye, coloured according to the agent ## Morphology - Grain: a compact microcolony of the agent surrounded by inflammation; collected from the discharge or by biopsy. - Eumycetoma: grains with broad septate hyphae; those of Madurella mycetomatis are black from melanin. - Actinomycetoma: grains of very fine bacterial filaments; usually white or yellow, and red with Actinomadura pelletieri. ## Transmission - Traumatic inoculation of contaminated soil or plant material (thorns, splinters, stones) into the skin. - Higher risk with walking barefoot and farm or manual work. - Not spread from person to person. **Reservoir:** Soil, vegetation and water of dry tropical and subtropical areas ### Isolation precautions What the care team adds to standard precautions. - Standard ## Virulence factors - Grains shield the agent from the immune system and from drugs. - Madurella melanin lowers azole activity in vitro. - Slow spread through tissue planes: skin, subcutis, muscle and bone, deforming the limb. ## Diseases it causes - Mycetoma (eumycetoma or actinomycetoma), mostly of the foot [Mycetoma (actinomycetoma and eumycetoma) →](https://durgical.com/en/conditions/mycetoma/) ## Clinical picture - A painless nodule that grows over months or years, with sinuses draining pus with grains. - Actinomycetoma reaches bone faster and is seen more often on the chest, abdomen or head. - Untreated, it leads to osteomyelitis, deformity and disability; sometimes amputation. ## Diagnosis - Direct exam and staining of grains from aspiration or biopsy: tells fungus from bacterium, which decides treatment. - Culture of the grain (can misidentify species) and PCR, the most reliable but costly and poorly standardised. - Imaging (X-ray, MRI) to see bone extension. ## Treatment It depends on the agent: actinomycetoma responds to prolonged combined antibiotics (e.g. trimethoprim-sulfamethoxazole, amikacin) with good cure rates; eumycetoma needs azole antifungals (mainly itraconazole) and nearly always surgery, and relapses are common. Drug class only; doses and regimens are set by the clinician from the current guideline. In Pharmacology: - [Trimethoprim](https://durgical.com/en/pharmacology/trimethoprim/) - [Amikacin](https://durgical.com/en/pharmacology/amikacin/) - [Itraconazole](https://durgical.com/en/pharmacology/itraconazole/) ## Prevention - Wearing shoes in endemic rural areas. - Early review of any chronic foot nodule: early diagnosis prevents disability. ## In Colombia Actinomycetoma predominates in the Americas, and Nocardia brasiliensis is one of its most frequent agents in the region; Colombia reports sporadic cases in rural workers. It is not a notifiable event and there are no national figures. ## Memory aid A foot with chimneys that puff out grains: each sinus is a chimney, and if the grain is black, blame the fungus. ## Test yourself Think of the answer, then tap the question to see it. ## Why does it matter whether a mycetoma is eumycetoma or actinomycetoma? Actinomycetoma is bacterial and is usually cured with antibiotics; eumycetoma is fungal, responds poorly to antifungals and nearly always needs surgery. ## How does a person acquire mycetoma? By inoculation of soil or plant debris into a small wound, such as a thorn while walking barefoot. It is not contagious. ## What does a black grain in mycetoma discharge suggest? Eumycetoma, typically from Madurella mycetomatis, whose pigment is melanin. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/microbiology/mycetoma-agents/) ## Related - [Nocardia](https://durgical.com/en/microbiology/nocardia/) - [Actinomyces israelii](https://durgical.com/en/microbiology/actinomyces-israelii/) - [Sporothrix schenckii](https://durgical.com/en/microbiology/sporothrix-schenckii/) - [Agents of chromoblastomycosis (Fonsecaea and other pigmented fungi)](https://durgical.com/en/microbiology/agents-of-chromoblastomycosis/) ## Related conditions - [Mycetoma (actinomycetoma and eumycetoma)](https://durgical.com/en/conditions/mycetoma/) ## What the colours mean **Gram-positive** Thick peptidoglycan wall: stains purple. **Gram-negative** Thin wall with an outer membrane: stains pink. **Acid-fast** Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain. [← Back to the group: Other fungi of clinical interest](https://durgical.com/en/microbiology/groups/other-fungi-of-clinical-interest/) Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Mycetoma](https://www.who.int/news-room/fact-sheets/detail/mycetoma) (WHO, 2022); [Mycetoma Basics | Mycetoma | CDC](https://www.cdc.gov/mycetoma/about/index.html) (CDC, 2024). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/microbiology/mycetoma-agents/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/mycetoma-agents/