Filamentous fungi that most frequently cause true fungaemia

Invasive fungal infections (IFIs) have become increasingly important over the past two decades, particularly due to the growing population of patients with compromised immunity. Rapidly progressive and aggressive infections are associated with high mortality and rather complex laboratory diagnostics. The most common form of IFI is fungaemia – the presence of fungi in the blood – which serve to spread the pathogen in the host and subsequently develop a systemic infection. Over 95% of fungaemia is caused by yeasts from the Candida genus, with a smaller proportion caused by other pathogenic fungi. Less common are moulds, which, because of their characteristic filamentous structures, do not enter the bloodstream like yeasts and therefore do not cause true fungaemia. However, the genera Aspergillus, Fusarium, Scedosporium, Lomentospora, Purpureocillium, and Paecilomyces cause true fungaemia and are thus an exception among filamentous fungi.