Phenotypic and molecular identification, susceptibility profile and cell wall glucuronoxylomannan expression of the emergent yeast Trichosporon spp.: analysis of invasive and colonizing isolates

Abstract

In the last three decades not only the incidence of fungal infections has increased significantly, but also the mortality and morbidity rates associated with them. Among the factors contributing to this phenomenon are the increase population of patients with severe immunosuppression and those solid organ and hematopoietic transplant recipients. In this scenario, some fungi, especially those of the genus Trichosporon, are considered emergent pathogens. Infections by this genus are difficult to diagnosis, resistant to many current antifungals, and are associated with elevated mortality rates. The difficulty in the identification of the Trichosporon species by classical methods, important to the definition of the therapeutic choice, and the elevated rates of drug resistance, together with the vulnerability of the immunosupressed patients and the lack of knowledge of the putative virulence factors, warrants investigations comparing invasive and colonizing isolates. Our study aims to demonstrate that molecular techniques help in the species identification as complement to the classical methods, in addition of evaluating if there are differences in species distribution, susceptibility profiles, and expression of the cell wall polysaccharide GXM between 20 invasive and 40 colonizing isolates from hospitalized patients. With this purpose, phenotypic and molecular methods will be employed. Also, antifungals susceptibility tests will be evaluated to determine resistance and sensitivity profile of these isolates. The GMX expression analysis will be determined by an ELISA assay employing monoclonal antibodies. (AU)