Chitin assay used to demonstrate renal localization and cortisone enhanced growth of Aspergillus fumigatus mycelium in mice

Abstract

Aspergillus fumigatus mycelium in untreated mice (N mice) and cortisone acetate treated mice (C mice) has been quantified by chemical assay of fungal chitin. Cortisone pretreatment rendered mice more susceptible to infection by A. fumigatus (mean lethal dose at 20 days, =106 for N mice; <104 for C mice). In both N and C mice there was renal localization of mycelial infection at conidial doses less than the mean lethal dose. At a conidial dose greater than the mean lethal dose, mycelial infection was found in the kidneys and brain of N mice and in the kidneys, liver, and heart of C mice. Chitin assay results showed that A. fumigatus mycelium grew more rapidly in C mice. It is suggested that the resistance of N mice to mycelial development may be an important mechanism whereby natural resistance to A. fumigatus is conferred.