Figure 1.

Mechanism of intestinal bacteria against C. albicans. Intestinal bacteria prevent the proliferation and colonization of C. albicans through various mechanisms. For example, Pseudomonas aeruginosa can produce phenazine, intracellular ROS production increased, mitochondrial membrane hyperpolarization, leading to the death of C. albicans; It can secrete lipopolysaccharide and improve EFG1 transcription in the hypoxia condition of biofilm environment, thereby stimulating glycolysis and inhibiting Candida hyphae-specific genes (HSGs), changing gene expression in biofilm formation and inhibiting hypha formation; Producing secretory lysophospholipase C, which degrades phosphatidylcholine and leads to the death of C. albicans; AHLs are produced that inhibit the C. albicans Ras1–cAMP–PKA pathway and reduce its virulence. Enterococcus faecalis can produce bacteriocin Entv, which can regulate the Frs system of C. albicans, secrete GelE, SprE and some extracellular proteases, inhibit the formation of C. albicans biofilm and hyphae, and reduce its toxicity. Acinetobacter baumannii can secrete OmpA and make it adhere to C. albicans to inhibit the formation of C. albicans hyphae and biofilm. The glycolipid substances secreted by Serratia marcescens have the characteristics of biosurfactant and can inhibit the formation of C. albicans biofilm. Bacillus can produce lipopeptide and also has the characteristics of biosurfactant, which can reduce the expression of HWP1 and ALS3 of C. albicans and inhibit its biofilm formation. Lactic acid bacteria can produce short-chain fatty acids and lactic acid, reduce the expression of HWP1, and inhibit the hyphal formation of C. albicans. Lactobacillus rhamnosus can secrete 1- acetyl-β-carboline (1-ABC) to inhibit the formation of C. albicans biofilm by inhibiting the fungal DYRK1 family kinase. Staphylococcus epidermidis can inhibit the biofilm formation of C. albicans, but its inhibition mechanism is still unclear.