Saccharide sources do not influence the biofilm formation in Scedosporium/Lomentospora species

Abstract

Scedosporium and Lomentospora species are ubiquitous saprophytic filamentous fungi that emerged as human pathogens with impressive multidrug-resistance profile. The ability to form biofilm over several biotic and abiotic surfaces is one of the characteristics that contributes to their resistance patterns against almost all currently available antifungals. Herein, we have demonstrated that Scedosporium apiospermum, Scedosporium minutisporum, Scedosporium aurantiacum and Lomentospora prolificans were able to form biofilm, in similar amounts, when conidial cells were incubated in a polystyrene substrate containing Sabouraud medium supplemented or not with different concentrations (2%, 5% and 10%) of glucose, fructose, sucrose and lactose. Likewise, the glucose supplementation of culture media primarily composed of amino acids (SCFM, synthetic cystic fibrosis medium) and salts (YNB, yeast nitrogen base) did not modulate the biofilm formation of Scedosporium/Lomentospora species. Collectively, the present data reinforce the ability of these opportunistic fungi to colonize and to build biofilm structures under different environmental conditions.

Cell dispersion during biofilm formation by Scedosporium apiospermum, Scedosporium aurantiacum, Scedosporium minutisporum and Lomentospora prolificans

“…Increasing concentrations of glucose (from 5 to 500 mM) did not modulate fungal dispersion, while an environment without available nutrients (e.g., PBS), significantly decreased dispersion when compared to the nutrient-rich medium (Sabouraud). As previously published by our research group, different glucose concentrations did not modulate biofilm formation dynamics in Scedosporium/Lomentospora species, reiterating the idea that these fungal species probably use other components of the culture medium, for example peptone, as a carbon source to sustain their basic metabolism ( Mello et al., 2020a ). The modulation of dispersion as a function of nutritional status is a survival strategy, in which cells propagate when a favorable environment is detected, while a cohesive biofilm is formed in a nutrient-poor environment ( Uppuluri et al., 2010 ).…”