Competitive interactions between bacteria and fungi are mainly described from the bacterial perspective. The negative effect of bacteria on fungi is most evident in fungal overgrowth after antibiotic treatment. Both in murine models and in humans, antibiotic treatment has been shown to support Candida spp. colonization and fungal overgrowth 185,207,208 . Intestinal bacteria have a diverse repertoire of molecules capable of disturbing fungal growth and differentiation 61 . Bacteria can reduce virulence factors of C. albicans by affecting their filamentation, adherence and biofilm formation [209][210][211][212] . Reduction of virulence factors of C. albicans may in turn lead to reduced protection of filamentous bacteria in mixed biofilms 61 . Future research should shed light on deleterious effects of fungi on bacteria, as these are currently understudied. As mentioned before, bacteria outnumber fungi substantially in the intestine. For this reason, future studies additionally need to account for the absolute abundance of bacteria and fungi in these interkingdom interactions.