Ginkgolic acids and Ginkgo biloba extract inhibit Escherichia coli O157:H7 and Staphylococcus aureus biofilm formation

Int J Food Microbiol. 2014 Mar 17;174:47-55. doi: 10.1016/j.ijfoodmicro.2013.12.030. Epub 2014 Jan 5.

Abstract

Infection by enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a worldwide problem, and there is no effective therapy. Biofilm formation is closely related to EHEC infection and is also a mechanism of antimicrobial resistance. Antibiofilm screening of 560 purified phytochemicals against EHEC showed that ginkgolic acids C15:1 and C17:1 at 5μg/ml and Ginkgo biloba extract at 100μg/ml significantly inhibited EHEC biofilm formation on the surfaces of polystyrene and glass, and on nylon membranes. Importantly, at their working concentrations, ginkgolic acids and G. biloba extract did not affect bacterial growth. Transcriptional analyses showed that ginkgolic acid C15:1 repressed curli genes and prophage genes in EHEC, and these findings were in-line with reduced fimbriae production and biofilm reductions. Interestingly, ginkgolic acids and G. biloba extract did not inhibit the biofilm formation of a commensal E. coli K-12 strain. In addition, ginkgolic acids and G. biloba extract inhibited the biofilm formation of three Staphylococcus aureus strains. The findings of this study suggest that plant secondary metabolites represent an important resource for biofilm inhibitors.

Keywords: Biofilm formation; Escherichia coli O157:H7; Fimbria; Ginkgolic acids; Staphylococcus aureus; Swarming.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Biofilms / drug effects*
  • Escherichia coli K12 / drug effects
  • Escherichia coli O157 / drug effects*
  • Escherichia coli O157 / genetics
  • Escherichia coli O157 / physiology
  • Gene Expression Regulation, Bacterial / drug effects
  • Ginkgo biloba / chemistry*
  • Plant Extracts / pharmacology*
  • Salicylates / pharmacology*
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / physiology

Substances

  • Anti-Bacterial Agents
  • Plant Extracts
  • Salicylates
  • ginkgolic acid