The Mycotoxin Zearalenone Hinders Biofilm Formation and Hyphal Morphogenesis.

Yeast-mold mycobiota inhabit several natural ecosystems, in which symbiotic relationships drive strategic pathoadaptation. Mycotoxins are metabolites produced by diverse mycotoxigenic fungi as a defense against yeasts, though at times yeasts secrete enzymes that degrade, detoxify, or bio-transform mycotoxins. The present study is focused on the in vitro inhibitory effects of zearalenone (ZEN), a F2 mycotoxin produced by several and species, on different microbial strains. ZEN exhibited no effect on the planktonic growth or biofilms of several Gram positive and negative bacteria at the tested concentrations. Remarkably, biofilm formation and hyphal morphogenesis were significantly inhibited when treated with 100 µg/mL of ZEN. Likewise, ZEN proficiently disrupted pre-formed biofilms without disturbing planktonic cells. Furthermore, these inhibitions were confirmed by crystal violet staining and XTT reduction assays and by confocal and scanning electron microscopy. In an in vivo model, ZEN significantly suppressed infection in the nematode . The study reports the in vitro antibiofilm efficacy of ZEN against strains, and suggests mycotoxigenic fungi participate in asymmetric competitive interactions, such as, amensalism or antibiosis, rather than commensal interactions with , whereby mycotoxins secreted by fungi destroy biofilms.