title: Antimicrobial and Virulence-Modulating Effects of Clove Essential Oil on the Foodborne Pathogen Campylobacter jejuni.
abstract: Our study investigated the antimicrobial action of clove (Syzygium aromaticum) essential oil (EO) on the zoonotic pathogen Campylobacter jejuni After confirming the clove essential oil's general antibacterial effect, we analyzed the reference strain Campylobacter jejuni NCTC 11168. Phenotypic, proteomic, and transcriptomic methods were used to reveal changes in cell morphology and functions when exposed to sublethal concentrations of clove EO. The normally curved cells showed markedly straightened and shrunken morphology on the scanning electron micrographs as a result of stress. Although, oxidative stress, as a generally accepted response to essential oils, was also present, the dominance of a general stress response was demonstrated by reverse transcription-PCR (RT-PCR). The results of RT-PCR and two-dimensional (2D) PAGE revealed that clove oil perturbs the expression of virulence-associated genes taking part in the synthesis of flagella, PEB1, PEB4, lipopolysaccharide (LPS), and serine protease. Loss of motility was also detected by a phenotypic test. Bioautographic analysis revealed that besides its major component, eugenol, at least four other spots of clove EO possessed bactericidal activity against C. jejuni Our findings show that clove EO has a marked antibacterial and potential virulence-modulating effect on C. jejuni IMPORTANCE: This study demonstrates that the components of clove essential oil influence not only the expression of general stress genes but also the expression of virulence-associated genes. Based on this finding, alternative strategies can be worked on to control this important foodborne pathogen.
authors: Department of Medical Microbiology and Immunology, University of Pécs, Pécs, Hungary.
authors: Judit K
authors: JK
authors: Kovács
authors: Department of Medical Microbiology and Immunology, University of Pécs, Pécs, Hungary.
authors: Péter
authors: P
authors: Felső
authors: Institute of Bioanalysis, University of Pécs, Pécs, Hungary.
authors: Lilla
authors: L
authors: Makszin
authors: Department of Biochemistry and Medical Chemistry, University of Pécs, Pécs, Hungary.
authors: Zoltán
authors: Z
authors: Pápai
authors: Department of Pharmacognosy, University of Pécs, Pécs, Hungary.
authors: Györgyi
authors: G
authors: Horváth
authors: Central Electron Microscope Laboratory, University of Pécs, Pécs, Hungary.
authors: Hajnalka
authors: H
authors: Ábrahám
authors: Department of Medical Microbiology and Immunology, University of Pécs, Pécs, Hungary.
authors: Tamás
authors: T
authors: Palkovics
authors: Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary.
authors: Andrea
authors: A
authors: Böszörményi
authors: Department of Medical Microbiology and Immunology, University of Pécs, Pécs, Hungary Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
authors: Levente
authors: L
authors: Emődy
authors: Department of Medical Microbiology and Immunology, University of Pécs, Pécs, Hungary gyorgy.schneider@aok.pte.hu.
authors: György
authors: G
authors: Schneider
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D016123:Campylobacter jejuni / Q000187:drug effects* / Q000378:metabolism / Q000472:pathogenicity; D005054:Eugenol / Q000032:analysis / Q000494:pharmacology; D009822:Oils, Volatile / Q000032:analysis / Q000494:pharmacology*; D027842:Syzygium / Q000737:chemistry*; D014774:Virulence / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D009822:Oils, Volatile; D005054:Eugenol