Essential Oils and Eugenols Inhibit Biofilm Formation and the Virulence of Escherichia coli O157:H7.
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity. Interestingly, these essential oils and eugenol did not inhibit biofilm formation by three laboratory E. coli K-12 strains that reduced curli fimbriae production. Transcriptional analysis showed that eugenol down-regulated 17 of 28 genes analysed, including curli genes (csgABDFG), type I fimbriae genes (fimCDH) and ler-controlled toxin genes (espD, escJ, escR, and tir), which are required for biofilm formation and the attachment and effacement phenotype. In addition, biocompatible poly(lactic-co-glycolic acid) coatings containing clove oil or eugenol exhibited efficient biofilm inhibition on solid surfaces. In a Caenorhabditis elegans nematode model, clove oil and eugenol attenuated the virulence of EHEC.
School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea.
Yong-Guy
YG
Kim
School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea.
Jin-Hyung
JH
Lee
School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea.
Giyeon
G
Gwon
Nareso Research Center, Seoho-ro 89, Suwon 16614, Republic of Korea.
Soon-Il
SI
Kim
Pohang Center for Evaluation of Biomaterials, Pohang Technopark Foundation, Pohang 37668, Republic of Korea.
Jae Gyu
JG
Park
School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea.
Jintae
J
Lee
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D017173:Caenorhabditis elegans / Q000382:microbiology; D004195:Disease Models, Animal; D004927:Escherichia coli Infections / Q000188:drug therapy; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics; D005054:Eugenol / Q000494:pharmacology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D009822:Oils, Volatile / Q000494:pharmacology*; D010933:Plankton; D010938:Plant Oils / Q000494:pharmacology; D014774:Virulence / Q000187:drug effects
D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D009822:Oils, Volatile; D010938:Plant Oils; D005054:Eugenol