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International Conference on
Veterinary Science

August 28-30, 2023 | London, UK
VET 2023

Bahar Nayeri Fasaei

Bahar Nayeri Fasaei, Speaker at Animal Science Conferences
Tehran university, Iran (Islamic Republic of)
Title : Different phylogenetic groups and pathotypes of extended spectrum ?-lactamase Escherichia coli strains in the intestine of broilers along breeding periods


Enterohemorrhagic Escherichia coli (EHEC) is a highly pathogenic strain leading to hemorrhagic colitis and to the hemolytic-uremic syndrome (HUS) in humans. EHEC is able to form biofilms on various biotic and abiotic surfaces, such as, on plants, stainless steel, glass, and polymers. In the present study we aimed to investigate the antibacterial, anti-biofilm and quorum sensing (QS) inhibitory potential of Thymus daenensis and Satureja hortensis essential oils (EOs) against E. coli O157:H7.

The plant EOs were extracted by hydrodistillation and their compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). The antibacterial and anti-biofilm potential of the tested EOs were determined by microdilution broth and microtiter-plate (MtP) tests, respectively. The QS inhibitory (QSI) potential of  T. daenensis and S. hortensis EOs was examined by inhibition of motility (swimming and swarming) at sub-MIC levels and determination of the expressions of two QS-system-related genes (luxS and pfs) at sub-MIC concentrations.

Based on microdilution broth, the MICs for T. daenensis and S. hortensis EOs against EHEC were 3.12 and 6.25 μg.ml-1, respectively. In addition, the MtP test showed a significant (p < 0.05) inhibitory and disruptive effects of both tested EOs on EHEC biofilm formation at MIC/2 (1.56 μg.ml-1 for T. daenensis; 3.12 μg.ml-1 for S. hortensis) and MIC/4 (0.78 μg.ml-1 for T. daenensis; 1.56 μg.ml-1 for S. hortensis) concentrations. Real time PCR showed a significant down-regulation of luxS and pfs following treatment with MIC/2 concentrations of both tested EOs.Accordingly, the present study highlighted the acceptable antibacterial, anti-biofilm and anti-QS potential of T. daenensis and S. hortensis EOs against E. coli O157:H7.

Keywords: Thymus daenensis, Satureja hortensis, Escherichia coli O157:H7, biofilm, quorum sensing