Project description:Campylobacter jejuni is an important foodborne pathogen causing campylobacteriosis. It can infect humans through the consumption of contaminated chicken products or via the direct handling of animals. Diallyl trisulfide (DATS) is a trisulfide compound from garlic extracts that has a potential antimicrobial effect on foodborne pathogens. This study investigated the antimicrobial activity of DATS on C. jejuni by evaluating the minimal inhibitory concentrations (MICs) of C. jejuni 81-168, and fourteen C. jejuni isolates from chicken carcasses. Thirteen of 14 C. jejuni isolates and 81-176 had MICs ≤ 32 μg/mL, while one isolate had MIC of 64 μg/mL. Scanning electron microscopy (SEM) analysis showed the disruption and shrink of C. jejuni bacterial cell membrane after the DATS treatment. A time-killing analysis further showed that DATS had a dose-dependent in vitro antimicrobial effect on C. jejuni during the 24 h treatment period. In addition, DATS also showed an antimicrobial effect in chicken through the decrease of C. jejuni colony count by 1.5 log CFU/g (cloacal sample) during the seven-day DATS treatment period. The transcriptional analysis of C. jejuni with 16 μg/mL (0.5× MIC) showed 210 differentially expression genes (DEGs), which were mainly related to the metabolism, bacterial membrane transporter system and the secretion system. Fourteen ABC transporter-related genes responsible for bacterial cell homeostasis and oxidative stress were downregulated, indicating that DATS could decrease the bacterial ability to against environmental stress. We further constructed five ABC transporter deletion mutants according to the RNA-seq analysis, and all five mutants proved less tolerant to the DATS treatment compared to the wild type by MIC test. This study elucidated the antimicrobial activity of DATS on C. jejuni and suggested that DATS could be used as a potential antimicrobial compound in the feed and food industry.
Project description:ObjectivesBacterial biofilms pose significant food safety risks because of their attachment to fomites and food surfaces, including fresh produce surfaces. The purpose of this study was to systematically investigate the activity of selected antimicrobials on Campylobacter jejuni biofilms.MethodsC. jejuni biofilms and planktonic cells were treated with ciprofloxacin, erythromycin and diallyl sulphide and examined using infrared and Raman spectroscopies coupled with imaging analysis.ResultsDiallyl sulphide eliminated planktonic cells and sessile cells in biofilms at a concentration that was at least 100-fold less than used for either ciprofloxacin or erythromycin on the basis of molarity. Distinct cell lysis was observed in diallyl sulphide-treated planktonic cells using immunoblot analysis and was confirmed by a rapid decrease in cellular ATP. Two phases of C. jejuni biofilm recalcitrance modes against ciprofloxacin and erythromycin were validated using vibrational spectroscopies: (i) an initial hindered adsorption into biofilm extracellular polymeric substance (EPS) and delivery of antibiotics to sessile cells within biofilms; and (ii) a different interaction between sessile cells in a biofilm compared with their planktonic counterparts. Diallyl sulphide destroyed the EPS structure of the C. jejuni biofilm, after which the sessile cells were killed in a similar manner as planktonic cells. Spectroscopic models can predict the survival of sessile cells within biofilms.ConclusionsDiallyl sulphide elicits strong antimicrobial activity against planktonic and sessile C. jejuni and may have applications for reducing the prevalence of this microbe in foods, biofilm reduction and, potentially, as an alternative chemotherapeutic agent for multidrug-resistant bacterial strains.
Project description:Campylobacter jejuni is a common cause of diarrheal disease worldwide. Human infection typically occurs through the ingestion of contaminated poultry products. We previously demonstrated that an attenuated Escherichia coli live vaccine strain expressing the C. jejuni N-glycan on its surface reduces the Campylobacter load in more than 50% of vaccinated leghorn and broiler birds to undetectable levels (responder birds), whereas the remainder of the animals were still colonized (non-responders). To understand the underlying mechanism, we conducted 3 larger scale vaccination and challenge studies using 135 broiler birds and found a similar responder/non responder effect. The submitted data were used for a genome-wide association study of the chicken responses to glycoconjugate vaccination against Campylobacter jejuni.
Project description:Campylobacter jejuni is the most prevalent cause of foodborne bacterial enteritis worldwide. This study aims at the characterisation of pathomechanisms and signalling in Campylobacter-induced diarrhoea in the human mucosa. During routine colonoscopy, biopsies were taken from patients suffering from campylobacteriosis. RNA-seq of colon biopsies was performed to describe Campylobacter jejuni-mediated effects. Mucosal mRNA profiles of acutely infected patients and healthy controls were generated by deep sequencing using Illumina HiSeq 2500. This data provide the basis for subsequent upstream regulator analysis.
Project description:Campylobacter jejuni is a human pathogen which causes campylobacteriosis, one of the most widespread zoonotic enteric diseases worldwide. Most cases of sporadic C. jejuni infection occur through the handling or consumption of undercooked chicken meat, or cross-contamination of other foods with raw poultry fluid. A common practice to combat Campylobacter infection is to treat chickens with chlorine which kills the microbe. This analysis aimed to elucidate the transcriptomic response of Campylobacter jejuni treated with hypochlorite through Illumina sequencing. C. jejuni was grown and treated with hypochlorite. Samples were taken 5, 20 and 45 min after treatment for RNAseq analysis.The data generated were compared to the transcriptome pre-exposure to determine C. jejuni's response to hypochlorite.
Project description:Campylobacter spp. cause food-borne illnesses worldwide due to contaminated food and cross-contamination. This is at least partly the result of Campylobacter resistance in the food production chain, as modern food production facilitates the emergence and spread of resistance through intensive use of antimicrobials and international trade in raw materials and food products. The biofilm 'lifestyle' of Campylobacter contributes to this spread as it enables them to withstand stress in the environment both outside and inside the host. Campylobacter adhesion and biofilm formation has major implications for the food industry, where biofilms can be persistent sources of contamination. In our study, we described how the proteome of C. jejuni is affected by the deletion of the luxS gene on the planktonic cell type of C. jejuni, which is the first step of biofilm formation. In C. jejuni, the presence of the luxS gene has been associated with several phenotypes, including intercellular signalling, motility, biofilm formation, host colonisation, virulence, autoagglutination, cellular adherence and invasion, oxidative stress and chemotaxis. Deletion of the luxS gene is associated with a reduction or absence of the above properties compared to wild type (Elvers and Park, 2002; Guerry et al., 2006; He et al., 2008; Jeon et al., 2003; Quiñones et al., 2009; Plummer et al., 2011; Plummer, 2012; Reeser et al., 2007).
Project description:Campylobacter jejuni is a major zoonotic pathogen transmitted to humans via the food chain. C. jejuni is prevalent in chickens, a natural reservoir for this pathogenic organism. Due to the importance of macrolide antibiotics in clinical therapy of human campylobacteriosis, development of macrolide resistance in Campylobacter has become a concern for public health.To facilitate understanding the molecular basis associated with the fitness difference between Erys and Eryr Campylobacter, we compared the transcriptomes between ATCC 700819 and its isogenic Eryr transformant T.L.101 using DNA microarray.
Project description:Expression arrays comparing Campylobacter jejuni 11168 before and after serial passage in C57 BL/6 IL-10 deficient mice. Gene expression was compared during exponential growth in Bolton broth.
Project description:Expression arrays comparing Campylobacter jejuni NCTC11168 during growth in the cecum of germ-free C57 BL/6 IL-10 knockout mice to C. jejuni NCTC11168 during growth in Bolton broth.