DISSEMINATED FUSARIOSIS: A EXPERIMENTAL MODEL IN VIVO

The species of Fusarium complex are responsible for the third overall cause of invasive opportunistic fungal infection in humans, considering the increasing number of individuals on situations of immunosuppression this mycosis has appeared more frequently in these patients... Although disseminated fusariosis is fatal, little is known about the pathophysiology of this fungal infection. Thus, the objective of this study was to evaluate the fungal burden in different organs of animals infected by Fusarium keratoplasticum, considering the immune status of the host. For this, male Balb/c mice (6–8 weeks old) were infected by intravenous route with a conidia suspension from the F. keratoplasticum (ATCC 36031), in different concentrations (104; 105; 106; 107 and 2 x 107 conidia/animal) into the lateral tail vein. The group of immunosuppressed animals received intraperitoneally cyclophosphamide (Sigma) 100 mg/kg body weight three days before and the same day of infection. All procediments were according to the requirements with ethics committee (CEUA 6975260716). After five days of infection the mice were euthanized and organs were aseptically removed for the fungal burden determination by CFU count. Comparing the immunological host condition, it was possible to observe that the group of immunosuppressed animals (IS) infected with the inoculum of 107 conidia died after 2 days of infection. Only with inoculum of 105 conidia, the experiments were able to follow up to 4 days of infection, and all organs analyzed (Liver, Spleen, Kidneys, Lung, Heart, and Brain) presented high fungal load in the group of immunosuppressed mice. In the group of immunocompetent mice, the fungal burden was lower and it was not possible to detect it in the brain. Comparing the different inoculums in immunosuppressed animals, it was possible to observe that the highest fungal burden was found in the spleen and kidneys, followed by liver, heart, brain and lung. In this experiment, it was possible to observe that for spleen, kidneys, liver and brain the recovered fungal load was dependent on the inoculum administered. For the heart and lung, this relation was not observed. Thus we can say that the experimental fusariosis model was established in both immunocompetent and immunosuppressed animals, opening perspectives for the pathophysiology studies of this relevant mycosis.