Effects of Essential Oils from <i>Cymbopogon</i> spp. and <i>Cinnamomum verum</i> on Biofilm and Virulence Properties of <i>Escherichia coli</i> O157:H7
Every year, the pharmaceutical and food industries produce over 1000 tons of essential oils (EOs) exploitable in different fields as the development of eco-friendly and safe antimicrobial inhibitors. In this work we investigated the potential of some EOs, namely <i>Cinnamomum verum</i>,...
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| Main Authors: | , , , , , , |
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| Format: | Book |
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MDPI AG,
2021-01-01T00:00:00Z.
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| Summary: | Every year, the pharmaceutical and food industries produce over 1000 tons of essential oils (EOs) exploitable in different fields as the development of eco-friendly and safe antimicrobial inhibitors. In this work we investigated the potential of some EOs, namely <i>Cinnamomum verum</i>, <i>Cymbopogon martini</i>, <i>Cymbopogon</i><i>citratus</i> and <i>Cymbopogon flexuosus</i>, on the growth, biofilm formation and gene expression in four strains of enterohemorrhagic <i>Escherichia coli</i> O157:H7. All EOs were analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity was performed by using dilutions of EOs ranging from 0.001 to 1.2% (<i>v</i>/<i>v</i>). Subinhibitory doses were used for biofilm inhibition assay. The expression profiles were obtained by RT-PCR. <i>E. coli</i> O157:H7 virulence was evaluated in vivo in the nematode <i>Caenorhabditis elegans</i>. All EOs showed minimal inhibitory concentrations (MICs) ranging from 0.0075 to 0.3% (<i>v</i>/<i>v</i>). <i>Cinnamomum verum</i> bark EO had the best activity (MIC of 0.0075% (<i>v</i>/<i>v</i>) in all strains) while the <i>C. verum</i> leaf EO had an intermediate efficacy with MIC of 0.175% (<i>v</i>/<i>v</i>) in almost all strains. The <i>Cymbopogon</i> spp. showed the more variable MICs (ranging from 0.075 to 0.3% (<i>v</i>/<i>v</i>)) depending on the strain used. Transcriptional analysis showed that <i>C. martini</i> EO repressed several genes involved in biofilm formation, virulence, zinc homeostasis and encoding some membrane proteins. All EOs affected zinc homeostasis, reducing <i>ykg</i>M and <i>zin</i>T expression, and reduced the ability of <i>E. coli</i> O157:H7 to infect the nematode <i>C. elegans</i>. In conclusion, we demonstrated that these EOs, affecting <i>E. coli</i> O157:H7 infectivity, have a great potential to be used against infections caused by microorganisms. |
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| Item Description: | 10.3390/antibiotics10020113 2079-6382 |