Human-impacted areas of France are environmental reservoirs of the Pseudallescheria boydii/Scedosporium apiospermum species complex.

Species of the Pseudallescheria boydii/Scedosporium apiospermum complex (PSC) are emerging fungal pathogens able to chronically colonize the airways of patients with cystic fibrosis (CF). As P. boydii was found more frequently colonizing the lungs of CF patients in France than in other European countries in a previous report, the present study was conducted in order to clarify distribution of PSC species in France and to characterize their natural habitat. The highest densities of PSC isolates were found in human-impacted areas, i.e. agricultural areas, fluids obtained from wastewater treatment plants, playgrounds and industrial areas. PSC was not detected from soil samples collected in forests. Most PSC culture-positive soil samples exhibited a pH range of 6-8. Scedosporium dehoogii, the most abundant species, was detected in all human-impacted area types except vineyards, whereas Scedosporium aurantiacum was mostly found in agricultural areas. Pseudallescheria boydii and S. apiospermum were predominantly isolated from seashores and playgrounds respectively. Pseudallescheria minutispora was found only once from a playground. This study highlights potential sources of contamination of the patients, especially in the CF context.

Distribution of the different species of the Pseudallescheria boydii/Scedosporium apiospermum complex in French patients with cystic fibrosis.

As various new sibling species within the Pseudallescheria boydii/Scedosporium apiospermum complex have been described recently with differences in their susceptibility to antifungals, this study was conducted in order to determine their respective frequency in cystic fibrosis. Results indicated that P. boydii largely predominated (62%), followed by S. apiospermum (24%), Scedosporium aurantiacum (10%) and Pseudallescheria minutispora (4%). Scedosporium dehoogii was not recovered in this study. The multiple correspondence factor analysis highlighted geographical discrepancies within species distribution: P. boydii was rarely encountered in Northern France, while S. apiospermum was less represented in the west of the country. Additionally, we demonstrated that all species encountered in the cystic fibrosis context were capable to chronically colonize the respiratory tract of patients. Molecular typing of a large set of environmental and clinical isolates should be conducted to delineate the epidemiology of each sibling species in the complex.

Scedosporium species in soils from various biomes in Northwestern Morocco.

Scedosporium species are opportunistic pathogens causing various infections, including disseminated infections in severely immunocompromised patients. Preventive measures aiming to reduce the risk of exposure to these fungi require a better knowledge on their ecology and on the sources of contamination of the patients. In this context, 99 soil samples from the Rabat-Sale-Kenitra and Fez-Meknes regions in Morocco were analyzed. Samples were inoculated on the highly selective Scedo-Select III culture medium, and seven chemical parameters of the soils were measured. Scedosporium species were detected in 48 of the samples, with the highest density in soils from wastewater treatment plants and landfills, followed by those from roadsides and polluted riverbanks, thus confirming the impact of human activities on their ecology. Scedosporium apiospermum was the most common species, followed by S. boydii and S. aurantiacum. Analysis of the chemical parameters of the soils revealed the presence of Scedosporium species was mainly associated with a moderate electrical conductivity, a pH range of 7.0 to 7.6, a nutrient-rich content and a moderate phosphorus amount. Thereby, these results demonstrated the relatively high occurrence of Scedosporium in Morocco and highlighted the impact of phosphorus content on their ecology.