• Guest speaker Dr Neil Stone

In this episode we are focussing on moulds other than Aspergillus spp. and Mucorales that can cause invasive infection in humans.

• We will be talking mainly about Fusarium spp., as well as Scedosporium spp. and Lomentospora prolificans
• These are all environmental pathogens that cause opportunistic infection in severely immunocompromised individuals or patients with underlying lung disease.
• These are all hyalohyphomycoses, which means they have clear or transparent hyphae (as opposed to dematiaceous fungi which have pigmented hyphae).

Fusarium spp.

Ubiquitous environmental moulds, found in the soil and air

The main species complexes that cause human infection are:

• F. solani complex - cause > 50% severe cases
• F. oxysporum complex - cause > 20% of severe cases

<aside> 💡

Think bananas!

F. oxysporum is a major banana plant pathogen, called ‘Fusarium wilt’ or ‘Panama disease’.

Under the microscope, Fusarium spp. have curved, banana-shaped macroconidia.

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Epidemiology

Invasive infection primarily occurs in the severely immunocompromised:

• haematological malignancy, HSCT, SOT recipients

Prolonged neutropenia is a major risk factor for acquiring disseminated disease

Pathogenesis

Main routes of infection are by inhalation of airborne conidia or direct inoculation through traumatic injuries / burns

Clinical features

Invasive disease

• Most commonly effects the skin, deep soft tissue, lungs or sinuses