Dataset Information

The natural antimicrobial carvacrol inhibits Campylobacter jejuni motility and infection of epithelial cells.

ABSTRACT:

Background

Natural compounds with anti-microbial properties are attractive reagents to reduce the use of conventional antibiotics. Carvacrol, the main constituent of oregano oil, inhibits the growth of a variety of bacterial foodborne pathogens. As concentrations of carvacrol may vary in vivo or when used in animal feed, we here investigated the effect of subinhibitory concentrations of the compound on major virulence traits of the principal bacterial foodborne pathogen Campylobacter jejuni.

Methods/principal findings

Motility assays revealed that subinhibitory concentrations of carvacrol inhibited the motility of C. jejuni without affecting bacterial growth. Immunoblotting and electron microscopy showed that carvacrol-treated C. jejuni still expressed flagella. The loss of motility was not caused by reduced intracellular ATP levels. In vitro infection assays demonstrated that subinhibitory concentrations of carvacrol also abolished C. jejuni invasion of human epithelial cells. Bacterial uptake of invasive Escherichia coli was not blocked by carvacrol. Exposure of C. jejuni to carvacrol prior to infection also inhibited cellular infection, indicating that the inhibition of invasion was likely caused by an effect on the bacteria rather than inhibition of epithelial cell function.

Conclusions/significance

Bacterial motility and invasion of eukaryotic cells are considered key steps in C. jejuni infection. Our results indicate that subinhibitory concentrations of carvacrol effectively block these virulence traits by interfering with flagella function without disturbing intracellular ATP levels. These results broaden the spectrum of anti-microbial activity of carvacrol and support the potential of the compound for use in novel infection prevention strategies.

SUBMITTER: van Alphen LB

PROVIDER: S-EPMC3458047 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

The natural antimicrobial carvacrol inhibits Campylobacter jejuni motility and infection of epithelial cells.

van Alphen Lieke B LB Burt Sara A SA Veenendaal Andreas K J AK Bleumink-Pluym Nancy M C NM van Putten Jos P M JP

PloS one 20120925 9

<h4>Background</h4>Natural compounds with anti-microbial properties are attractive reagents to reduce the use of conventional antibiotics. Carvacrol, the main constituent of oregano oil, inhibits the growth of a variety of bacterial foodborne pathogens. As concentrations of carvacrol may vary in vivo or when used in animal feed, we here investigated the effect of subinhibitory concentrations of the compound on major virulence traits of the principal bacterial foodborne pathogen Campylobacter jej ...[more]

PMID: 23049787

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Project description:Campylobacter jejuni is a major foodborne pathogen that causes gastroenteritis in humans. Chickens act as the reservoir host for C. jejuni, wherein the pathogen asymptomatically colonizes the ceca leading to contamination of carcasses during slaughter. The major colonization factors in C. jejuni include motility, intestinal epithelial attachment, acid/bile tolerance, and quorum sensing. Reducing the expression of the aforementioned factors could potentially reduce C. jejuni colonization in chickens. This study investigated the efficacy of subinhibitory concentration (SIC; compound concentration not inhibiting bacterial growth) of carvacrol in reducing the expression of C. jejuni colonization factors in vitro. Moreover, the effect of carvacrol on the expression of C. jejuni proteome was investigated using liquid chromatography-tandem mass spectrometry. The motility assay was conducted at 42°C, and the motility zone was measured after 24 h of incubation. For the adhesion assay, monolayers of primary chicken enterocytes (?105 cells/well) were inoculated with C. jejuni (6 log cfu/well) either in the presence or absence of carvacrol, and the adhered C. jejuni were enumerated after 90 min of incubation at 42°C. The effect of carvacrol on C. jejuni quorum sensing and susceptibility to acid/bile stress was investigated using a bioluminescence assay and an acid-bile survival assay, respectively. The SIC (0.002%) of carvacrol reduced the motility of C. jejuni strains S-8 and NCTC 81-176 by ?50 and 35%, respectively (P < 0.05). Carvacrol inhibited C. jejuni S-8 and NCTC 81-176 adhesion to chicken enterocytes by ?0.8 and 1.5 log cfu/mL, respectively (P < 0.05). Moreover, carvacrol reduced autoinducer-2 activity and increased the susceptibility of C. jejuni to acid and bile in both the strains (P < 0.05). Liquid chromatography-tandem mass spectrometry revealed that the SIC of carvacrol reduced the expression of selected C. jejuni colonization proteins critical for motility (methyl-accepting chemotaxis protein), adhesion (GroL), growth and metabolism (AspA, AcnB, Icd, Fba, Ppa, AnsA, Ldh, Eno, PurB-1), and anaerobic respiration (NapB, HydB, SdhA, NrfA) (P < 0.05). Results suggest the mechanisms by which carvacrol could reduce C. jejuni colonization in chickens.

Dataset Information

The natural antimicrobial carvacrol inhibits Campylobacter jejuni motility and infection of epithelial cells.

Background

Methods/principal findings

Conclusions/significance

Publications

The natural antimicrobial carvacrol inhibits Campylobacter jejuni motility and infection of epithelial cells.

Similar Datasets

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