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Speakers - 2025

Bahar Nayeri Fasaei - 2nd Edition of the Infectious Disease World Conference

Bahar Nayeri Fasaei

Bahar Nayeri Fasaei

  • Designation: Associated professor. Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
  • Country: Iran
  • Title: Thymus daenensis and Satureja hortensis essential oils inhibit biofilm formation and quorum sensing of Escherichia coli O157:H7

Biography

I am a Bahar Nayeri Fasaei associate professor in the faculty of veterinary medicine at Tehran University. I have worked there for 15 years. 

Abstract

Abstract

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 potentials 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, respectively. In addition, the MtP test showed significant (p < 0.05) inhibitory and disruptive effects of both tested EOs on EHEC biofilm formation at MIC/2 (1.56 μg/ml for T. daenensis; 3.12 μg/ml for S. hortensis) and MIC/4 (0.78 μg/ml for T. daenensis; 1.56 μg/ml 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

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