Regulation of gene transcription in Escherichia coli O157:H7 in response to a natural derivate peptide of Esculentin-1a used in combination with essential oils from plants of the Cymbopogon genus.

Abstract

Introduction. We analyzed the expression of several genes implicated in the pathogenicity of Escherichia coli O157:H7, treating bacteria with Esc(1-21), a derivative of peptide esculentin-1 in combination with three essential oils obtained from plants from the Cympopogon genus.
Methods. We used the checkerboard assay to determine the antimicrobial activity of the combinations. We analyzed the expression of some genes implicated in the pathogenicity and quorum sensing system of E. coli O157:H7 by real-time RT-PCR technique.
Results. Treatment of the bacteria with the peptide combined with oils had an efficacious antimicrobial activity. The analysis of gene expression showed that all used combinations regulate positively the espAD and ler genes, located in the pathogenicity island, named the locus of enterocyte effacement. None of the combinations affects the quorum sensing genes: lsrABCFKR and qseBC.
Conclusions. This study demonstrates that the use of essential oil/peptide combinations can be effective in fighting microbial infections.