Anti-biofilm and associated anti-virulence activities of sucrose fatty acid esters against human pathogens

Sucrose fatty acid esters, such as SP50 and SP70, are widely used commercially as emulsifiers. This study aimed to evaluate the impact of these surfactants on the survival of pathogenic microorganisms, as well as their anti-adhesive and biofilm-resistant properties. The antimicrobial, anti-adhesive and antibiofilm activities of SP50 and SP70 were evaluated in the concentration range of 0.0156-1 mg/ml. Complete growth inhibition was achieved for Escherichia coli with both compounds at a concentration of 1 mg/ml, while for the rest of the strains was found to be 67.04-16.35% for SP50, while for SP70 was 75.87-17.74% at the highest concentration. The results demonstrated that both sucrose fatty acid esters effectively inhibited the expression of virulence genes in Enterococcus faecalis (cstR, efaA, ESP) and Klebsiella pneumoniae (ompK35, mrkA, arcB) strains derived from the human gastric system. Furthermore, the mRNA expression of hyphal-specific genes (HWP1, EAP1, EGF1, ECE1, SAP5) in Candida albicans was significantly reduced without causing substantial growth inhibition. Additional assays confirmed that the tested compounds exhibited no cytotoxicity toward normal human dermal fibroblast (NDHF) and human colon adenocarcinoma (HT-29) cell lines. However, they notably inhibited the formation of C. albicans biofilm on these cell surfaces and exhibited anti-inflammatory properties against this microorganism. These findings suggest that SP50 and SP70 may be effective agents for controlling biofilm formation on food and solid surfaces. Moreover, their potential as novel antibiotics warrants further investigation in more complex biological systems.