Thiophenone and furanone in control of Escherichia coli O103:H2 virulence.

Escherichia coli are a mutual and foodborne pathogen, causing severe intestinal infections typically characterized by diarrhoea and vomiting. Biofilms are often a common source of pathogenic and nonpathogenic bacteria. Quorum sensing is a phenomenon where bacteria communicate and initiate the regulation of several virulence factors and biofilm formation. Thus, quorum sensing has been a new target in the fight against bacterial biofilms. In this study, we investigated the effect of two quorum-sensing inhibitors for preventing in vitro biofilm formation in wild-type E. coli O103:H2. Furanone F202 originates from the red algae Delisea pulchra, and thiophenone TF101 is a sulphur analogue of furanone. We also investigated the effect of thiophenone and furanone on virulence factors controlled by quorum sensing. Both TF101 and F202 interfered with biofilm formation, although TF101 was more effective. TF101 reduced motility presumably by interfering with flagella production, visualized by microscopic techniques. The expressions of flhd, which are involved in flagella synthesis, were affected by thiophenone. This is the first study exploring the effect of thiophenone on E. coli biofilm formation and virulence factors.