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 Cinnamomum verum, Cymbopogon martini, Cymbopogoncitratus and Cymbopogon flexuosus, on the growth, biofilm formation and gene expression in four strains of enterohemorrhagic Escherichia coli 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% (v/v). Subinhibitory doses were used for biofilm inhibition assay. The expression profiles were obtained by RT-PCR. E. coli O157:H7 virulence was evaluated in vivo in the nematode Caenorhabditis elegans. All EOs showed minimal inhibitory concentrations (MICs) ranging from 0.0075 to 0.3% (v/v). Cinnamomum verum bark EO had the best activity (MIC of 0.0075% (v/v) in all strains) while the C. verum leaf EO had an intermediate efficacy with MIC of 0.175% (v/v) in almost all strains. The Cymbopogon spp. showed the more variable MICs (ranging from 0.075 to 0.3% (v/v)) depending on the strain used. Transcriptional analysis showed that C. martini EO repressed several genes involved in biofilm formation, virulence, zinc homeostasis and encoding some membrane proteins. All EOs affected zinc homeostasis, reducing ykgM and zinT expression, and reduced the ability of E. coli O157:H7 to infect the nematode C. elegans. In conclusion, we demonstrated that these EOs, affecting E. coli O157:H7 infectivity, have a great potential to be used against infections caused by microorganisms.

中文翻译：

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Cymbopogon spp精油的作用。和肉桂对大肠杆菌O157：H7生物膜和毒力特性的影响

每年，制药和食品工业生产1000吨以上的精油（EOs），可用于环保和安全的抗菌抑制剂的开发，可用于不同领域。在这项工作中，我们研究了一些EOs，即肉桂，Cymbopogon martini，Cymbopogon citratus和Cymbopogon flexuosus在四株肠出血性大肠杆菌中的生长，生物膜形成和基因表达的潜力。O157：H7。通过气相色谱-质谱法（GC-MS）分析所有EO。通过使用浓度范围为0.001至1.2％（v / v）的EOs进行抗菌活性。亚抑制剂量用于生物膜抑制测定。表达谱通过RT-PCR获得。在线虫秀丽隐杆线虫（Caenorhabditis elegans）的体内评估了大肠杆菌O157：H7的毒力。所有EO均显示最小抑菌浓度（MIC），范围为0.0075至0.3％（v / v）。肉桂皮EO具有最佳的活性（在所有菌株中MIC为0.0075％（v / v）），而在几乎所有菌株中，C。verum叶EO的中效均为MIC为0.175％（v / v）。该香茅spp。取决于所使用的应变，显示出更多可变的MIC（范围从0.075到0.3％（v / v））。转录分析表明，马提尼梭菌EO抑制了一些与生物膜形成，毒力，锌稳态和编码某些膜蛋白有关的基因。所有受影响个EO锌体内平衡，减少YKG M和ZIN Ť表达，并减少的能力的大肠杆菌O157：感染线虫H7线虫。总之，我们证明了这些影响大肠杆菌O157：H7感染力的EO具有巨大的潜力可用于抵抗由微生物引起的感染。