Low Concentrations of Honey Can Reduce Colonization, Virulence of E. coli

Low Concentrations of Honey Reduce Biofilm Formation, Quorum Sensing, and Virulence in Escherichia coli O157:H7
Biofouling, 2011 Nov;27(10):1095-104

Bacterial biofilms are associated with persistent infections due to their high resistance to antimicrobial agents. Hence, controlling pathogenic biofilm formation is important in bacteria-related diseases.

Honey, at a low concentration of 0.5% (v/v), significantly reduced biofilm formation in enterohemorrhagic Escherichia coli O157:H7 without inhibiting the growth of planktonic cells. Conversely, this concentration did not inhibit commensal E. coli K-12 biofilm formation.

Transcriptome analyses showed that honey significantly repressed curli genes (csgBAC), quorum sensing genes (AI-2 importer and indole biosynthesis), and virulence genes (LEE genes). Glucose and fructose in the honeys were found to be key components in reducing biofilm formation by E. coli O157:H7 through the suppression of curli production and AI-2 import. Furthermore, honey, glucose and fructose decreased the colonization of E. coli O157:H7 cells on human HT-29 epithelial cells.

These results suggest that low concentrations of honey, such as in honeyed water, can be a practical means for reducing the colonization and virulence of pathogenic E. coli O157:H7.