Isolate-Dependent Growth, Virulence, and Cell Wall Composition in the Human Pathogen <i>Aspergillus fumigatus</i>

<div><p>The ubiquitous fungal pathogen <i>Aspergillus fumigatus</i> is a mediator of allergic sensitization and invasive disease in susceptible individuals. The significant genetic and phenotypic variability between and among clinical and environmental isolates are important considerations in host-pathogen studies of <i>A. fumigatus</i>-mediated disease. We observed decreased radial growth, rate of germination, and ability to establish colony growth in a single environmental isolate of <i>A. fumigatus</i>, Af5517, when compared to other clinical and environmental isolates. Af5517 also exhibited increased hyphal diameter and cell wall β-glucan and chitin content, with chitin most significantly increased. Morbidity, mortality, lung fungal burden, and tissue pathology were decreased in neutropenic Af5517-infected mice when compared to the clinical isolate Af293. Our results support previous findings that suggest a correlation between <i>in vitro</i> growth rates and <i>in viv</i>o virulence, and we propose that changes in cell wall composition may contribute to this phenotype.</p>