Chirality differences of three borneols contribute to controlling Escherichia coli biofilm formation by chemotaxis mediating movement

Escherichia coli (E. coli) biofilm is the major cause of its high lethality in foodborne illness. Controlling E. coli biofilm formation is a critical way to reduce foodborne diseases. Here, chiral borneol isomers (L-borneol, D-borneol, and isoborneol) were identified as E. coli chemorepellents, which reduced reversible adhesion at the initial stage of biofilm formation. Borneols directly inhibited biofilm production and their inhibitory capacities were associated with the chiral stereochemical structures (L-borneol > D-borneol > isoborneol). A transcriptomic study revealed the inhibitory mechanism of borneols was attributed to the bacterial motility intention and motility energy system. The most effective isomer, L-borneol, reduced bacterial energy metabolism and increased E. coli chemotaxis motility intention through the up-regulation of genes associated with flagellar assembly and bacterial chemotaxis pathways. This work demonstrates that borneols are biofilm inhibitors and supports the potential of borneols as a stereochemical antimicrobial strategy to reduce foodborne pathogenic bacterial contamination.