Elevated Temperature, Nitrate and Diesel Oil Enhance the Distribution of the Opportunistic Pathogens Scedosporium spp.

Abstract

Scedosporium infections mainly occur after aspiration of contaminated water or inoculation with polluted environmental materials. Scedosporium spp. have been isolated from anthropogenic environments frequently. To understand their propagation and routes of infection, possible reservoirs of Scedosporium spp. should be explored. In this study, the impact of temperature, diesel and nitrate on Scedosporium populations in soil is described. Soil was treated with diesel and KNO3 and incubated for nine weeks at 18 and 25 °C. Isolation of Scedosporium strains was done using SceSel+. For the identification of 600 isolated strains, RFLP and rDNA sequencing were used. Scedosporium apiospermum, S. aurantiacum, S. boydii and S. dehoogii were isolated at the beginning and/or the end of incubation. Temperature alone had a minor effect on the Scedosporium population. The combination of 25 °C and nitrate resulted in higher Scedosporium numbers. Treatment with 10 g diesel/kg soil and incubation at 25 °C resulted in even higher abundance, and favored S. apiospermum and S. dehoogii. The results of this study show that diesel-polluted soils favor dispersal of Scedosporium strains, especially S. apiospermum and S. dehoogii. Higher temperature force the effect of supplementations.