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Campylobacter spp. are the leading cause of bacterium-derived gastroenteritis worldwide, impacting 96 million individuals annually. Unlike other bacterial pathogens of the gastrointestinal tract, Campylobacter spp. lack many of the classical virulence factors that are often associated with the ability to induce disease in humans, including an array of canonical secretion systems and toxins. Consequently, the clinical manifestations of human campylobacteriosis and its resulting gastrointestinal pathology are believed to be primarily due to the host immune response toward the bacterium. Further, while gastrointestinal infection is usually self-limiting, numerous postinfectious disorders can occur, including the development of Guillain-Barré syndrome, reactive arthritis, and irritable bowel syndrome. Because gastrointestinal disease likely results from the host immune response, the development of these postinfectious disorders may be due to dysregulation or misdirection of the same inflammatory response. As a result, it is becoming increasingly important to the Campylobacter field, and human health, that the cellular immune responses toward Campylobacter be better understood, including which immunological events are critical to the development of disease and the postinfectious disorders mentioned above. In this review, we collectively cover the cellular immune responses across susceptible hosts to Campylobacter jejuni infection, along with the tissue pathology and postinfectious disorders which may develop.

Campylobacter concisus is a human-pathogenic bacterium of the gastrointestinal tract. This study aimed at the contribution of the mucosal immune system in the context of intestinal epithelial barrier dysfunction induced by C. concisus . As an experimental leaky gut model, we used in vitro co-cultures of colonic epithelial cell monolayers (HT-29/B6-GR/MR) with M1-macrophage-like THP-1 cells on the basal side. Forty-eight hours after C. concisus infection, the decrease in the transepithelial electrical resistance in cell monolayers was more pronounced in co-culture condition and 22 ± 2% ( p < 0.001) higher than the monoculture condition without THP-1 cells. Concomitantly, we observed a reduction in the expression of the tight junction proteins occludin and tricellulin. We also detected a profound increase in 4 kDa FITC-dextran permeability in C. concisus -infected cell monolayers only in co-culture conditions. This is explained by loss of tricellulin from tricellular tight junctions (tTJs) after C. concisus infection. As an underlying mechanism, we observed an inflammatory response after C. concisus infection through pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) released from THP-1 cells in the co-culture condition. In conclusion, the activation of subepithelial immune cells exacerbates colonic epithelial barrier dysfunction by C. concisus through tricellulin disruption in tTJs, leading to increased antigen permeability (leaky gut concept).

Spotty Liver Disease (SLD) is an emerging disease of serious concern in the egg production industry, as it causes significant egg loss and mortality in layer hens. The causative agent is a newly identified Gram-negative bacterium, Campylobacter hepaticus, and knowledge about C. hepaticus pathogenesis and the potential for vaccine development is still in its infancy. Current detection methods for SLD, such as PCR and culturing, only detect an active infection and will not give any indication of a past infection from which the bacteria have been cleared. An immunological assay, on the other hand, can provide information on previous infections and therefore is crucial in vaccine development against SLD. In the present study, we have developed the first immunoassay capable of detecting C. hepaticus -specific antibodies present in the sera of infected birds. The assay uses C. hepaticus total protein extract (TPE) as the antigen coating on enzyme-linked immunosorbent assay (ELISA) plates. The cross reactivity of C. hepaticus antibodies with closely related C. jejuni and C. coli antigens was successfully overcome by pre-absorbing the sera using C. jejuni cell extracts. The assay was validated using sera samples from both naturally- and experimentally-infected birds, birds vaccinated with formalin-killed bacteria, and serum samples from SLD-negative birds (control group). The optimized ELISA assay had 95.5% specificity and 97.6% sensitivity. The immunoassay provides a useful tool for monitoring the exposure of poultry flocks to C. hepaticus infection and can be used to direct and support vaccine development. HIGHLIGHTS The first immunoassay developed for Spotty Liver Disease (SLD). A useful method for detecting C. hepaticus -specific antibodies in birds. Highly specific (95.5%) and sensitive (97.6%) assay. A key tool for use in epidemiological studies and vaccine development.

Campylobacter jejuni colonizes the chicken gut at a high density without causing disease. However, consumption of poultry products contaminated with this bacterium causes gastroenteritis in humans. Therefore, it is critically important to reduce the Campylobacter burden in poultry products to prevent transmission to humans. Evidence indicates that enhancing intestinal mucosal immune responses is of paramount importance for preventing or reducing Campylobacter colonization in chickens. In view of this, the present study was undertaken to evaluate host responses to different C. jejuni-derived ligands, including lipooligosaccharide (LOS), outer membrane proteins (OMPs), and genomic DNA, with the ultimate goal of identifying a ligand with potent immunostimulatory capacity to serve as a mucosal vaccine adjuvant against enteric infections in chickens. The results revealed that C. jejuni pathogen-associated molecular patterns (PAMPs) varied in their ability to induce the expression of cytokines and chemokines in chicken macrophages and cecal tonsil mononuclear cells and nitric oxide production in macrophages. In addition, C. jejuni OMPs demonstrated superior activity over LOS and DNA ligands in eliciting cytokine expression associated with T helper (Th)1 and Th2 responses (interferon [IFN]-γ and interleukin [IL]-13, respectively), in addition to expression of pro-inflammatory cytokines (IL-1β), chemokine (CXCLi2), and regulatory cytokines (IL-10 and TGFβ1/4) in cecal tonsil cells. Importantly, in addition to their ability to induce innate responses, OMPs could also function as antigens to elicit C. jejuni-specific antibody responses and thereby confer dual protection against C. jejuni infection. Further studies are required to assess the protective efficacy of C. jejuni OMPs against C. jejuni infection in chickens., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2020. Published by Elsevier B.V.)

Background: Lytic bacteriophages that infect Campylobacter spp. have been utilized to develop therapeutic/decontamination techniques. However, the association of Campylobacter spp. and bacteriophages has been the focus of several strands of research aimed at understanding the complex relationships that have developed between predators and prey over evolutionary time. The activities of endogenous temperate bacteriophages have been used to evaluate genomic rearrangements and differential protein expression in host cells, and mechanisms of resistance to bacteriophage infection in campylobacters such as phase variation and CRISPR-mediated immunity., Results: Temperate bacteriophage DA10 represents a novel excised and infective virus capable of replication in a restricted set of C. jejuni and C. coli hosts. Whole genome sequencing reveals that DA10 (35,379 bp) forms part of a novel group of temperate bacteriophages that have limited distribution among database host genome sequences. Analysis of potential host genomes reveals a robust response against DA10 and DA10-like bacteriophages is driven by CRISPR-mediated immunity with 75% of DA10 ORFs represented as ~ 30 bp spacer sequences in numerous Campylobacter Type II-C CRISPR arrays. Several DA10-like homologues have been identified in a small sub-set of C. jejuni and C. coli genome sequences (ranging from near complete integrated prophage sequences to fragments recognisable in the sequence read archive)., Conclusions: A complete intact DA10-like prophage in C. jejuni CJ677CC520 provides evidence that the associations between host and DA10-like bacteriophages are long-standing in evolutionary timescales. Extensive nucleotide substitution and loss can be observed in the integrated DA10-like prophage of CJ677CC520 compared to other relatives as observed through pairwise genome comparisons. Examining factors that have limited the population expansion of the prophage, while others appear to have thrived and prospered (Mu-like, CJIE-like, and lytic Campylobacter bacteriophages) will assist in identifying the underlying evolutionary processes in the natural environment.

Campylobacteriosis is a widespread infectious disease, leading to a major health and economic burden. Chickens are considered as the most common infection source for humans. Campylobacter mainly multiplies in the mucus layer of their caeca. No effective control measures are currently available, but passive immunisation of chickens with pathogen-specific maternal IgY antibodies, present in egg yolk of immunised chickens, reduces Campylobacter colonisation. To explore this strategy further, anti-Campylobacter nanobodies, directed against the flagella and major outer membrane proteins, were fused to the constant domains of chicken IgA and IgY, combining the benefits of nanobodies and the effector functions of the Fc-domains. The designer chimeric antibodies were effectively produced in leaves of Nicotiana benthamiana and seeds of Arabidopsis thaliana. Stable expression of the chimeric antibodies in seeds resulted in production levels between 1% and 8% of the total soluble protein. These in planta produced antibodies do not only bind to their purified antigens but also to Campylobacter bacterial cells. In addition, the anti-flagellin chimeric antibodies are reducing the motility of Campylobacter bacteria. These antibody-containing Arabidopsis seeds can be tested for oral passive immunisation of chickens and, if effective, the chimeric antibodies can be produced in crop seeds., Competing Interests: The authors have declared that no competing interests exist.

Background: We aimed to estimate population-level exposure to Campylobacter and associated risk factors, using three approaches for serological data analysis., Methods: Nationwide, population-based serosurvey in the Netherlands (Feb 2006-Jun 2007). Anti-Campylobacter IgG, IgM and IgA were measured using ELISA, and analysed via: a) seroincidence estimation, using reference values of antibody peak levels and decay rates over-time after Campylobacter exposure; b) two normal distributions of true positives/negatives fitted to the IgG distribution to derive seroprevalence and individual probability of being positive/negative; and c) IgG levels. Risk factors were analysed using multiple linear regressions., Results: From 1559 respondents, seroincidence was estimated at 1.61 infections/person-year (95%CI:1.58-1.64) and seroprevalence at 68.1% (65.4-70.9). The three approaches identified similar risk factors, although seroincidence had higher power and results were interpretable as risk: seroincidence was higher in females [exp(b) = 1.07(1.04-1.11)], older ages [vs. 15-34 years; for < 5, 5-14, 35-54 and 55-70 years: 0.60(0.58-0.63), 0.74(0.71-0.78), 1.08(1.03-1.13) and 1.08(1.01-1.16), respectively], non-Dutch background [Moroccan/Turkish: 1.25(1.14-1.37); Caribbean: 1.14(1.03-1.25)], low socioeconomic status [1.05(1.01-1.10)], traveling outside Europe [1.05(1.01-1.09)], and eating undercooked meat [1.04(1.01-1.08)]., Conclusion: Campylobacter exposure is much higher than clinical infection rates, but risk factors are similar to those previously described.Seroincidence is a powerful measure to study Campylobacter epidemiology, and is preferred over other methods., (Copyright © 2018 The British Infection Association. Published by Elsevier Ltd. All rights reserved.)

The detection of campylobacters in stools is performed essentially by culture, but this technique has a low sensitivity. New detection methods are now available. Among them, immunochromatography tests (ICTs) are very attractive in that they offer a result within 15 min. However, previous studies suggest that these tests have a relatively low specificity. The objective of this study was to evaluate the performance of these tests. During the study period, all patients who consulted the emergency units and had a stool culture were included. Their stool samples were tested with two ICTs, Ridaquick Campylobacter and Immuno Card STAT! Campy. Stools were also tested by a home-made PCR and two commercially available enzyme-linked immunosorbent assays (ELISAs) when one of the ICTs was positive. The composite reference standard (CRS) was defined as positive if the culture was positive or, in case of a negative culture, if the PCR and one of the ELISAs were positive simultaneously. Three hundred and five patients were included. Among the 50 positive specimens with Ridaquick Campylobacter, 47 were considered true positives by the CRS, corresponding to a positive predictive value (PPV) of 94.0%. Among the 52 positive specimens with Immuno Card STAT! Campy, 44 were considered true positives by the CRS, corresponding to a PPV of 84.6%. The negative predictive values were estimated at 94.9 and 92.4% for the Ridaquick Campylobacter and Immuno Card STAT! Campy tests, respectively. ICTs appear to be very efficient and allow a very rapid detection of campylobacters, which is important for treating early campylobacter infections with an adapted antibiotherapy., (Copyright © 2018 American Society for Microbiology.)

Campylobacter is the leading cause of human bacterial gastroenteritis in the European Union. Birds represent the main reservoir of the bacteria, and human campylobacteriosis mainly occurs after consuming and/or handling poultry meat. Reducing avian intestinal Campylobacter loads should impact the incidence of human diseases. At the primary production level, several measures have been identified to reach this goal, including vaccination of poultry. Despite many studies, however, no efficient vaccine is currently available. We have recently identified new vaccine candidates using the reverse vaccinology strategy. This study assessed the in vivo immune and protective potential of six newly-identified vaccine antigens. Among the candidates tested on Ross broiler chickens, four (YP&#95;001000437.1, YP&#95;001000562.1, YP&#95;999817.1, and YP&#95;999838.1) significantly reduced cecal Campylobacter loads by between 2 and 4.2 log10 CFU/g, with the concomitant development of a specific humoral immune response. In a second trial, cecal load reductions results were not statistically confirmed despite the induction of a strong immune response. These vaccine candidates need to be further investigated since they present promising features.

The newly developed rapid diagnostic test (RDT, DK14-CA1, Denka Seiken Co., Ltd.) to detect Campylobacter antigen was evaluated using fecal specimens of patients with enteritis. The RDT is an immunochromatographic assay using colored latex and can detect Campylobacter antigen (C. jejuni and C. coli) from patients' stool samples within 15 minutes. A total of 227 stool samples obtained from patients with enteritis were examined and the results were compared with conventional culture methods. Overall sensitivity, specificity, accuracy and positive predictive value (PPV) were 75.6%, 98.6%, 89.9% and 97.0% respectively. Among 53 severe cases defined with their clinical findings, sensitivity, specificity, accuracy and PPV were 82.1%, 100%, 90.6% and 100% respectively. Mean time to obtain the result with the RDT was 7 minutes whereas the culture method took 2.2 days. This study revealed the usefulness of the newly developed RDT as a rapid detection tool for Campylobacter antigen. Although the RDT has a little lower sensitivity compared with culture method, the simple and rapid test can contribute to treatment decisions for patients with enteritis and can be used at the patient's bedside and in outpatient clinics.

Campylobacter species, particularly thermotolerant Campylobacter spp., such as C. jejuni, are major human foodborne pathogens. Culture methods have been routinely used for the detection of this organism in various types of samples. An alternative, simple and rapid confirmation test(s) without further tedious biochemical tests would be useful. Meanwhile, Campylobacter-like colonies can be difficult to identify on agar plates overgrown with competitive bacteria, which can lead to false-negative results. This study was to develop a simple colony blot immunoassay using a new monoclonal antibody (Mab) produced in the present study for rapid screening, confirmation and quantification of campylobacters on culture agar plates. The procedure developed in this study was able to specifically detect thermotolerant Campylobacter spp., but not other non-thermotolerant Campylobacter and non-Campylobacter reference strains tested. This assay could detect 10 5 cells in a single dot. This assay showed 100% correlation with the culture method for the blotted membranes from 21 either chicken meat or vegetable samples experimentally inoculated with thermotolerant campylobacters. Among 101 natural samples of chicken meat (n=44), chicken feces (n=20) and vegetables (n=37), this assay also showed positive for 23 chicken meat and 14 fecal samples that were positive for thermotolerant campylobacters by culture method, and identified four additional suspects that were culture negative. Membranes stored at 4°C for at least 4years could also be used for this assay. The assay developed in this study can be used in quantitative study for immediate or archival usage, and for diagnostic test to preliminarily confirm the presence of thermotolerant Campylobacter on agar plates., (Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.)

Helicobacter and Campylobacter species are Gram-negative microaerophilic host-associated heterotrophic bacteria that invade the digestive tract of humans and animals. Campylobacter jejuni is the major worldwide cause of foodborne gastroenteritis in humans, while Helicobacter pylori is ubiquitous in over half of the world's population causing gastric and duodenal ulcers. The colonisation of the gastrointestinal system by Helicobacter and Campylobacter relies on numerous cellular defences to sense the host environment and respond to adverse conditions, including those imposed by the host immunity. An important antimicrobial tool of the mammalian innate immune system is the generation of harmful oxidative and nitrosative stresses to which pathogens are exposed during phagocytosis. This review summarises the regulators, detoxifying enzymes and subversion mechanisms of Helicobacter and Campylobacter that ultimately promote the successful infection of humans.

Limited information is available on the systemic immunoglobulin response in patients infected with the emerging pathogen Campylobacter concisus. The aim of the present study was to detect anti-C. concisus antibodies in serum of 88 patients with C. concisus gastroenteritis. Specific IgG antibodies to C. concisus were measured in serum using an in-house enzyme-linked immunosorbent assay, and pooled donor serum was used as a control. The mean optical density was 0.135 (SEM: 0.020) for the 88 adult patients and 0.100 (SEM: 0.011) in controls. When using an optical density value equal to the mean +3 SEM for the control serum, 22 (25%) C. concisus-positive patients had increased IgG antibodies. Patients with high IgG levels more often reported headache, and they had a trend toward more mucus in stools, whereas IgG levels were unrelated to age, duration of diarrhea, number of stools per day, and weight loss., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Campylobacter concisus is an emerging pathogen of the gastrointestinal tract that has been associated with Barrett's oesophagus, enteritis and inflammatory bowel disease. Despite having invasive potential in intestinal epithelial cells in-vitro, bacteraemic cases with C. concisus are extremely scarce, having only been reported once. Therefore, we conducted a serum resistance assay to investigate the bactericidal effects of human complement on C. concisus in comparison to some other Campylobacter species. In total, 22 Campylobacter strains were tested by incubation with normal human serum and subsequent cultivation in microaerobic conditions for 48 hours. Killing time was evaluated by decrease in total CFU over time for incubation with different serum concentrations. Faecal isolates of C. concisus showed inoculum reduction to less than 50% after 30 min. Campylobacter jejuni was sensitive to serum, but killing was delayed and a bacteraemic Campylobacter fetus subsp. fetus isolate was completely serum resistant. Interestingly, sensitivity of enteric C. concisus to human serum was not associated to different faecal-calprotectin levels. We find that faecal isolates of C. concisus are sensitive to the bactericidal effects of serum, which may explain why C. concisus is not associated to bacteraemia., (© 2015 APMIS. Published by John Wiley & Sons Ltd.)

Pathogenic species within the genus Campylobacter are responsible for a considerable burden on global health. Campylobacter concisus is an emergent pathogen that plays a role in acute and chronic gastrointestinal disease. Despite ongoing research on Campylobacter virulence mechanisms, little is known regarding the immunological profile of the host response to Campylobacter infection. In this study, we describe a comprehensive global profile of innate immune responses to C. concisus infection in differentiated THP-1 macrophages infected with an adherent and invasive strain of C. concisus. Using RNA sequencing (RNA-seq), quantitative PCR (qPCR), mass spectrometry, and confocal microscopy, we observed differential expression of pattern recognition receptors and robust upregulation of DNA- and RNA-sensing molecules. In particular, we observed IFI16 inflammasome assembly in C. concisus-infected macrophages. Global profiling of the transcriptome revealed the significant regulation of a total of 8,343 transcripts upon infection with C. concisus, which included the activation of key inflammatory pathways involving CREB1, NF-κB, STAT, and interferon regulatory factor signaling. Thirteen microRNAs and 333 noncoding RNAs were significantly regulated upon infection, including MIR221, which has been associated with colorectal carcinogenesis. This study represents a major advance in our understanding of host recognition and innate immune responses to infection by C. concisus., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

In 1991, 1999 and 2006, randomly selected individuals from the Danish Central Personal Register provided a serum sample. From individuals aged 30 years and above, 500 samples from each year were analysed for Campylobacter IgG, IgA and IgM antibodies using a direct ELISA method. We applied a seroincidence calculator available from the European Centre for Disease Prevention and Control to perform a mathematical back-calculation to estimate the annual Campylobacter seroincidence in the Danish population. The estimated Campylobacter seroincidence did not differ significantly between the 1991, 1999 and 2006 studies although the reported number of culture-confirmed cases of Campylobacter infection increased 2.5 fold from 1993 to 1999 among individuals aged 30 years and above. This suggests that Campylobacter was widely present in the Danish population before the increase in poultry-associated clinical Campylobacter infections observed from 1993 to 2001 among individuals of this age groups.

Campylobacter jejuni and Campylobacter coli are recognized as the leading causes of human diarrheal disease throughout the development world. Unlike human beings, gastrointestinal tract of pigs are frequently colonized by Campylobacter to a high level in a commensal manner. The aim of this study was to identify the differences underlying the divergent outcome following Campylobacter challenge in porcine versus human host. In order to address this, a comparative in vitro infection model was combined with microscopy, gentamicin protection assay, ELISA and quantitative PCR techniques. Invasion assays revealed that Campylobacter invaded human cells up to 10-fold more than porcine cells (p<0.05). In addition, gene expression of proinflammatory genes encoding for IL1α, IL6, IL8, CXCL2 and CCL20 were strongly up-regulated by Campylobacter in human epithelial cell at early times of infection, whereas a very reduced cytokine gene expression was detected in porcine epithelial cells. These data indicate that Campylobacter fails to invade porcine cells compared to human cells, and this leads to a lack of proinflammatory response induction, probably due to its pathogenic or commensal behavior in human and porcine host, respectively., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: The aim of this study was to determine antibody titres against Campylobacter, Salmonella, and Yersinia in a population-based cohort of pregnant women in Denmark in order to evaluate adverse pregnancy outcomes (miscarriage, preterm birth, and small for gestational age) in relation to occupational exposure to animals in women exposed to food producing animals., Methods: We used data and blood samples from the Danish National Birth Cohort. Serum samples collected during the first trimester from 192 pregnant women who were occupationally exposed to domestic animals and 188 randomly selected unexposed pregnant women were analysed for IgG, IgM, and IgA antibodies against Campylobacter, Salmonella, and Yersinia. Pregnancy outcomes of interest were identified through the Danish National Patient Register., Results: Women with occupational exposure to animals had significantly higher IgG antibody concentrations against Campylobacter, Salmonella, and Yersinia, whereas they had lower concentrations of IgM and IgA antibodies., Conclusions: Serological markers were not identified as risk factors for adverse pregnancy outcomes, with the exception of elevated concentrations of Salmonella antibodies, which were found to be associated with an increased risk of preterm birth.

The study objective was to evaluate the effectiveness of the new rapid immunochromatographic test RIDAQUICK Campylobacter® (r-biopharm AG, Darmstadt, Germany) for the qualitative detection of Campylobacter antigens in pathologic feces from primary and specialist care patients. Three hundred feces samples were studied from patients with diarrhea, 50.6% from adults and 49.4% from children, which were received by our microbiology laboratory for coproculture. Campylobacter culture results, with or without PCR data, served as reference values for the comparative evaluation of RIDAQUICK Campylobacter® findings. Campylobacter was detected in 12.3% of samples. The diagnostic accuracy values of the RidaQuick Campylobacter® versus culture were: sensitivity of 87%, specificity of 97%, and positive and negative predictive values of 77% and 98%, respectively. RIDAQUICK Campylobacter® is a rapid test for the diagnosis of enteritis due to Campylobacter and could be an option for the clinical diagnosis of one of the main causes of bacterial enteritis in resource-limited settings., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The STAT! Campy immunochromatographic assay for Campylobacter antigen was compared to culture for 500 clinical stool specimens. Antigen was detected in six culture-negative, PCR-positive specimens. C. upsaliensis, a pathogenic species that is traditionally difficult to recover in routine stool cultures, was detected in two of these culture-negative specimens. This study provides evidence that antigen testing may cross-react with at least one additional non-jejuni and -coli Campylobacter species that may be missed by routine culture for campylobacteriosis.

Campylobacter antigen detection by enzyme immunoassay (EIA) provides rapid results compared to traditional culture. However, concern exists regarding specificity. Verification studies of an EIA compared to culture revealed a positive predictive value (PPV) of 91%, whereas PPV fell to 42% during routine diagnostic testing. We suggest all positive EIA results be confirmed via culture.

The foodborne bacterial pathogen, Campylobacter jejuni, possesses an N-linked protein glycosylation (pgl) pathway involved in adding conserved heptasaccharides to asparagine-containing motifs of >60 proteins, and releasing the same glycan into its periplasm as free oligosaccharides. In this study, comparative genomics of all 30 fully sequenced Campylobacter taxa revealed conserved pgl gene clusters in all but one species. Structural, phylogenetic and immunological studies showed that the N-glycosylation systems can be divided into two major groups. Group I includes all thermotolerant taxa, capable of growth at the higher body temperatures of birds, and produce the C. jejuni-like glycans. Within group I, the niche-adapted C. lari subgroup contain the smallest genomes among the epsilonproteobacteria, and are unable to glucosylate their pgl pathway glycans potentially reminiscent of the glucosyltransferase regression observed in the O-glycosylation system of Neisseria species. The nonthermotolerant Campylobacters, which inhabit a variety of hosts and niches, comprise group II and produce an unexpected diversity of N-glycan structures varying in length and composition. This includes the human gut commensal, C. hominis, which produces at least four different N-glycan structures, akin to the surface carbohydrate diversity observed in the well-studied commensal, Bacteroides. Both group I and II glycans are immunogenic and cell surface exposed, making these structures attractive targets for vaccine design and diagnostics.

Campylobacteriosis is the most common cause of bacterial foodborne illness in the European Union and the United States. Infection with Campylobacter spp. is frequently associated with different sequelae including neuropathies and reactive arthritis. Diagnosis is mainly by bacterial culturing which is time consuming, expensive, and not well suited for diagnosing sequelae or identifying infections from stool samples with nonviable bacteria. Serologic assays, in particular ELISAs, are well suited for this purpose, but, at present, there is no international consensus on antibody assays for human campylobacteriosis. In an extensive literature review, 19 studies validating such assays were identified of which 13 were more than 10 years old. We conclude that the best validated of these assays are developed and used in-house for research purposes rather than for routine diagnostics. Considering the burden of disease and potential long-term severity of Campylobacter infections, developing a standardized, commercially available antibody assay could be of great benefit for diagnostic and surveillance purposes worldwide., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: In the United States, considerable geographic variation in the rates of culture-confirmed Campylobacter infection has been consistently observed among sites participating in the Foodborne Diseases Active Surveillance Network (FoodNet)., Methods: We used data from the FoodNet Population Surveys and a FoodNet case-control study of sporadic infection to examine whether differences in medical care seeking, medical practices, or risk factors contributed to geographic variation in incidence., Results: We found differences across the FoodNet sites in the proportion of persons seeking medical care for an acute campylobacteriosis-like illness (range, 24.9%-43.5%) and in the proportion of ill persons who submitted a stool sample (range, 18.6%-40.7%), but these differences were not statistically significant. We found no evidence of geographic effect modification of previously identified risk factors for campylobacteriosis in the case-control study analysis. The prevalence of some exposures varied among control subjects in the FoodNet sites, including the proportion of controls reporting eating chicken at a commercial eating establishment (18.2%-46.1%); contact with animal stool (8.9%-30.9%); drinking water from a lake, river, or stream (0%-5.1%); and contact with a farm animal (2.1%-12.7%). However, these differences do not fully explain the geographic variation in campylobacteriosis., Conclusions: Future studies that quantify Campylobacter contamination in poultry or variation in host immunity may be useful in identifying sources of this geographic variation in incidence.

On-farm vaccination of chickens against Campylobacter jejuni is considered a potentially effective countermeasure to decrease campylobacteriosis via consumption of contaminated chicken meat, but is not yet available. In this study, 2 groups of Jidori chicks were immunized subcutaneously with a formalin-killed C. jejuni with 2 different adjuvants. Other chicks served as the unvaccinated control group. Both vaccines induced high levels of anti-Campylobacter IgG but did not decrease bacterial excretion in cecal droppings and bacterial load in the liver and spleen after oral challenge with 10(5) CFU of the homologous strain. Further study is needed to address the observed irrelevance and to develop a novel effective vaccine against C. jejuni.

Intestinal antigen encounter leads to recirculation of antigen-specific plasmablasts via lymphatics and blood back to the intestine. Investigating these gut-originating cells in blood provides a less invasive tool for studying intestinal immune responses, with the limitation that the cells disappear from the circulation in two weeks. No data exist on situations where pathogens persist in the intestine. Patients with Salmonella, Yersinia, or Campylobacter gastroenteritis and volunteers receiving an oral typhoid vaccine were assayed for plasmablasts specific to each subject's own pathogen/antigen weekly until the response faded. In vaccinees, plasmablasts disappeared in two weeks. In gastroenteritis, the response faded 2-3 and 3-7 weeks after the last positive Salmonella or Yersinia stool culture. Even in symptomless patients, pathogens persisting in the intestine keep seeding plasmablasts into the circulation. Assaying these cells might offer a powerful tool for research into diseases in which persisting microbes have a potential pathogenetic significance.

Campylobacter concisus is an emerging pathogen of the human gastrointestinal tract. Recently, a significantly higher prevalence of C. concisus DNA and higher levels of antibodies specific to C. concisus was detected in children with Crohn's disease when compared with controls. The aim of this study was to identify C. concisus immunoreactive antigens. Proteins from C. concisus were separated using two-dimensional gel electrophoresis, and sera from 10 C. concisus-positive children with Crohn's disease were employed for immunoprobing. The patients' sera reacted with 69 spots, which corresponded to 31 proteins identified by mass spectrometry. The proteins were functionally classified as involved in chemotaxis, signal transduction, flagellar motility, surface binding and membrane protein assembly. Although the individual patients' sera reacted to different sets of proteins, common antigens that were recognized by all patients were flagellin B, ATP synthase F1 alpha subunit, and outer membrane protein 18. Cross-reactivity between proteins of the Campylobacter genus was tested using patients' sera absorbed with Campylobacter showae, Campylobacter jejuni and Campylobacter ureolyticus. Most of the C. concisus immunoreactive proteins identified in this study showed cross-reactivity with other species except for three antigens. In conclusion, this study has identified C. concisus proteins that are immunoreactive within patients with Crohn's disease., (© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

Whereas the worldwide incidence of Crohn's disease (CD) continues to rise, Maori and Pacific Islanders living in New Zealand remain largely unaffected. The reason for this is currently unknown but may be linked to emerging evidence suggesting a role for Campylobacter spp in the aetiology of CD. Rates of campylobacteriosis are notably lower among Maori and Pacific Islanders and while this may reflect poorer access to primary care and diagnostic services, resulting in lower rates of notified disease, we consider it may also reflect a level of protective immunity in Maori and Pacific Islanders as a result of chronic infection from an early age with the closely related gastric pathogen Helicobacter pylori. Understanding the interactions between these antigenically-related bacteria may provide us with clues that ultimately help unravel the complex aetiology of CD.

Several infectious agents may cause arthritis or arthropathy. For example, infection with Borrelia burgdorferi, the etiologic agent of Lyme disease, may in the late phase manifest as arthropathy. Infections with Campylobacter, Salmonella, or Yersinia may result in a postinfectious reactive arthritis. Acute infection with parvovirus B19 (B19V) may likewise initiate transient or chronic arthropathy. All these conditions may be clinically indistinguishable from rheumatoid arthritis. Here, we present evidence that acute B19V infection may elicit IgM antibodies that are polyspecific or cross-reactive with a variety of bacterial antigens. Their presence may lead to misdiagnosis and improper clinical management, exemplified here by two case descriptions. Further, among 33 subjects with proven recent B19V infection we found IgM enzyme immunoassay (EIA) positivity for Borrelia only; for Borrelia and Salmonella; for Borrelia and Campylobacter; and for Borrelia, Campylobacter, and Salmonella in 26 (78.7%), 1 (3%), 2 (6%), and 1 (3%), respectively; however, when examined by Borrelia LineBlot, all samples were negative. These antibodies persisted over 3 months in 4/13 (38%) patients tested. Likewise, in a retrospective comparison of the results of a diagnostic laboratory, 9/11 (82%) patients with confirmed acute B19V infection showed IgM antibody to Borrelia. However, none of 12 patients with confirmed borreliosis showed any serological evidence of acute B19V infection. Our study demonstrates that recent B19V infection can be misinterpreted as secondary borreliosis or enteropathogen-induced reactive arthritis. To obtain the correct diagnosis, we emphasize caution in interpretation of polyreactive IgM and exclusion of recent B19V infection in patients examined for infectious arthritis or arthropathy.

Background: Campylobacter concisus and other non-Campylobacter jejuni Campylobacter species have been implicated in the initiation of gastrointestinal diseases. In the present study, we investigated the interaction between these bacteria and the human intestinal epithelium and immune cells., Methods: The ability of C. concisus, Campylobacter showae, Campylobacter hominis, and Bacteroides ureolyticus to invade epithelial cells was examined using scanning electron microscopy and gentamicin protection assays. Proinflammatory cytokines generated by epithelial and immune cells in response to these bacteria were determined by enzyme-linked immunosorbent assay. Ussing Chamber, immunofluorescent stain, and Western blot were used to further elucidate the impact of C. concisus on intestinal barrier integrity and functions., Results: Attachment of non-C. jejuni Campylobacter species to Caco-2 or HT-29 cells was mediated by flagellum-dependent and/or -independent processes. C. concisus was able to invade Caco-2 cells, generate a membrane-ruffling effect on the epithelial surface on entry, and damage epithelial barrier functions by preferential attachment to the cell-cell junctions. Proinflammatory cytokine profiles exhibited by epithelial cells, monocytes, and macrophages in response to C. concisus and other non-C. jejuni Campylobacter species were species and strain specific., Conclusions: These findings demonstrate that C. concisus and other non-C. jejuni Campylobacter species may play a role in initiating gastrointestinal diseases.

A simple and rapid method to detect Campylobacter spp. in chicken-meat samples was established. This method consisted of a combination of a two-step enrichment method with a commercially available immunochromatographic assay, named NH Immunochromato Campylobacter (NH IC Campy, Nippon Meat Packers, Ibaraki, Japan), which is able to detect Campylobacter antigen in an enrichment culture within 15 min. The enrichment method did not require much blood or a particular system of generating a microaerobic atmosphere, in contrast to the standard method of enriching Campylobacter spp. in chicken-meat samples. The sensitivity of a combination of the two-step enrichment method with NH IC Campy for detection of non- and freeze-stressed Campylobacter spp. in spiked chicken meat was determined using bacterial cells of Campylobacter jejuni and Campylobacter coli. The detection sensitivities for non-stressed C. jejuni and C. coli were found to range from 5.5 to 1.3x10(1) CFU per 25 g of chicken meat, and those for freeze-stressed C. jejuni and C. coli were found to range from 9.2x10(1) to 1.5x10(2) CFU per 25 g of chicken meat. When a total of 68 chicken-meat samples were tested, the combination method determined that 61 samples were positive for Campylobacter spp. This method was more sensitive than a bacterial culture test, which consists of standard enrichment culturing and plating onto selective agars. Because the combination could be conducted in approximately 48 h, from the beginning of the enrichment culture to final determination, it was more rapid than the bacterial culture test, which requires four to five days. Moreover, the combination was simple to perform. These results suggest that combining the two-step enrichment method with NH IC Campy is useful as a simple and rapid alternative to the conventional bacterial culture test for detecting Campylobacter spp. in naturally contaminated chicken meat samples., (Copyright 2010 Elsevier B.V. All rights reserved.)

Campylobacter infection in humans is accompanied by severe inflammation of the intestinal mucosa, in contrast to colonization of chicken. The basis for the differential host response is unknown. Toll-like receptors (TLRs) sense and respond to microbes in the body and participate in the induction of an inflammatory response. Thus far, the interaction of Campylobacter with chicken TLRs has not been studied. Here, we investigated the potential of four Campylobacter strains to activate human TLR1/2/6, TLR4, TLR5, and TLR9 and chicken TLR2t2/16, TLR4, TLR5, and TLR21. Live bacteria showed no or very limited potential to activate TLR2, TLR4, and TLR5 of both the human and chicken species, with minor but significant differences between Campylobacter strains. In contrast, lysed bacteria induced strong NF-kappaB activation through human TLR1/2/6 and TLR4 and chicken TLR2t2/16 and TLR4 but not via TLR5 of either species. Interestingly, C. jejuni induced TLR4-mediated beta interferon in human but not chicken cells. Furthermore, isolated chromosomal Campylobacter DNA was unable to activate human TLR9 in our system, whereas chicken TLR21 was activated by DNA from all of the campylobacters tested. Our data are the first comparison of TLR-induced immune responses in humans and chickens. The results suggest that differences in bacterial cell wall integrity and in TLR responses to Campylobacter LOS and/or DNA may contribute to the distinct clinical manifestation between the species.

The Gram-negative bacterium Campylobacter is the most common bacterial cause of human gastroenteritis in the United States and many industrialized countries. Poultry, particularly chickens, is considered a major source of human campylobacteriosis. Thus, on-farm control of Campylobacter in poultry would reduce the risk of human exposure to this pathogen and have a significant impact on food safety and public health. To date, three general strategies have been proposed to control Campylobacter in poultry at the farm level: (1) reduction of environmental exposure (biosecurity measures), (2) an increase in poultry's host resistance to reduce Campylobacter carriage in the gut (e.g., competitive exclusion, vaccination, and host genetics selection), and (3) the use of antimicrobial alternatives to reduce and even eliminate Campylobacter from colonized chickens (e.g., bacteriophage therapy and bacteriocin treatment). Except for biosecurity measures, the other intervention approaches are currently not commercially available and are still under development. This review is focused on two promising strategies--vaccination and bacteriocin treatment. In particular, we extensively review recent research aimed at discovering and characterizing potent anti-Campylobacter bacteriocins to reduce Campylobacter load at the primary production level in poultry.

DNA aptamers were developed against MgCl(2)-extracted surface proteins from Campylobacter jejuni. The two highest affinity aptamers were selected for use in a magnetic bead (MB) and red quantum dot (QD)-based sandwich assay scheme. The assay was evaluated using both heat-killed and live C. jejuni and exhibits detection limits as low as an average of 2.5 colony forming unit (cfu) equivalents in buffer and 10-250 cfu in various food matrices. The assay exhibits low cross-reactivity with bacterial species outside the Campylobacter genus, but exhibits substantial cross-reactivity with C. coli and C. lari. The assay was evaluated with a spectrofluorometer and a commercially available handheld fluorometer, which yielded comparable detection limits and ranges. Remarkably, the sandwich assay components adhere to the inside face of polystyrene cuvettes even in food matrices near neutral pH, thereby enabling a rapid homogeneous assay, because fluorescence is concentrated to a small, thin planar area and background fluorescence from the bulk solution is minimized. The plastic cuvette-adherent technology coupled to a sensitive handheld fluorometer may enable rapid (15-20 min), portable detection of foodborne pathogens from "farm-to-fork" by obviating the slow enrichment culture phase used by other food safety tests.

Acquired immunity is an important factor in the epidemiology of campylobacteriosis in the developing world, apparently limiting symptomatic infection to children of less than two years. However, also in developed countries the highest incidence is observed in children under five years and the majority of Campylobacter infections are asymptomatic, which may be related to the effects of immunity and/or the ingested doses. Not accounting for immunity in epidemiological studies may lead to biased results due to the misclassification of Campylobacter-exposed but apparently healthy persons as unexposed. In risk assessment studies, health risks may be overestimated when immunity is neglected.

We have previously shown that Campylobacter jejuni strains do not produce a functional cholera toxin-like toxin (CTLT) detectable in a Chinese hamster ovary cell assay. Instead, the 53-kDa major outer membrane protein (OMP) of C. jejuni, PorA, reacts with cholera toxin (CT) antibody on immunoblots. Here, we have extended this observation to other species of Campylobacter, including C. coli, C. lari, C. fetus, C. hyointestinalis, and C. upsaliensis, the common 53-kDa OMP of which reacted with CT antibody in immunoblotting assays. There were additional reactive bands for C. fetus. As with C. jejuni, this finding may lead to the erroneous conclusion that these additional species produce a functional CTLT. However, this common cross-reactive OMP can be explored as a vaccine candidate to prevent campylobacteriosis.

Campylobacter (C.) jejuni and C. coli can cause gastrointestinal disorders in humans characterized by acute inflammation. Inflammatory signals are initiated during interaction between these pathogens and human intestinal cells, but nothing is known about the stimulation of avian intestinal cells by Campylobacter. Interleukin-8 (IL-8) as a proinflammatory chemokine plays an important role in mobilizing cellular defence mechanism. IL-8 mRNA expression in both human intestinal cells (INT 407) and primary intestinal chick cells (PIC) was determined by quantitative real-time RT-PCR. The secretion of IL-8 protein by INT407 was measured using ELISA. Although C. jejuni and C. coli are considered to be harmless commensals in the gut of birds, the avian Campylobacter isolates investigated were able to induce the proinflammatory IL-8 in PIC as well as in INT407. In an in vitro system, C. jejuni as well as C. coli were able to induce IL-8 mRNA in PIC. Relation between the virulence properties like toxin production, the ability to invade and to survive in Caco-2 cells and the level of IL-8 mRNA produced by INT 407 and PIC after infection with Campylobacter strains was also investigated.

Weeks or months following Campylobacter infection, a small proportion of infected individuals develop Guillain-Barré syndrome (GBS) or reactive arthritis (ReA). Stool culture for Campylobacter is often negative in these patients, and serology is therefore the method of choice for diagnosing a recent infection with Campylobacter. This study developed a capture ELISA system to detect anti-Campylobacter IgA and IgM antibodies indicative of a recent infection. The sensitivity of the assay was 82.0% in uncomplicated Campylobacter enteritis patients, 96.2% in GBS patients who were culture-positive for Campylobacter, and 93.1% in culture-positive ReA patients, with a specificity of 93.0%. The assay allows identification of Campylobacter infection in patients with post-infectious neurological and rheumatological complications.

The gram-negative bacterium Campylobacter is the leading cause of bacterial entero-colitis in humans and is associated with the occurrence of life-threatening auto-immune based neurological disorders. Chickens, which are often heavily colonized with Campylobacter without signs of pathology, are considered the most important source for human infection. Although vaccination is a well established and effective method to combat various microbes in poultry, a commercial vaccine against Campylobacter has not yet been developed. For the development of such a vaccine, three main challenges can be identified: (1) the identification of novel cross-protection-inducing antigens, (2) the induction of a rapid, potent immune response, and (3) the development of novel adjuvants to further stimulate immunity against Campylobacter. The rapidly emerging knowledge of the biology of Campylobacter in combination with the recent advances in the fields of molecular vaccinology and immunology provide the required setting for the development of an effective vaccine against Campylobacter in poultry.

We hypothesised that some complex regional pain syndromes (CRPS) may have a postinfectious and/or autoimmune basis. Sera from 92 patients with CRPS and 92 controls were investigated for immunoreactivity to Campylobacter strains and to rodent tissues. Both IgA-antibodies to Campylobacter and tissue-specific reactivity were often present in patients with short disease duration (< or = 1.5 years). Patients with minimal preceding trauma had stronger nervous tissue-specific reactivity than other patients, regardless of disease duration. These results provide preliminary evidence for immune activation early in CRPS and, additionally, that patients with minimal trauma may comprise an autoimmune subgroup.

Background: The measurement of serum antibodies to Campylobacter spp. has been used to investigate links between prior Campylobacter infections and the development of Guillain-Barre syndrome and its variants. Little is known of the serum antibody response to acute infections in the short- or long-term., Aims: The aims of the present study were to investigate the normal serum response to an acute Campylobacter infection and the sensitivity and specificity of anti-Campylobacter antibodies in determining recent Campylobacter infection., Methods: An enzyme-linked immunosorbent assay (ELISA) method was used to measure serum anti-Campylobacter immunoglobulin G (IgG), IgA and IgM antibodies. Controls consisted of 420 blood donors without recent gastroenteritis, 25 patients with other gastrointestinal infections, 24 patients with neurological conditions not affecting the peripheral nerves and 19 patients with autoimmune disorders. Three patient groups were assessed: 99 patients with acute Campylobacter infections, all of whom were tested 3 weeks post-infection; 69 of these patients tested 3-6 months later; and 74 additional patients tested >20 months post-infection. Western blot analysis was performed on controls and patients with high titre anti-Campylobacter antibodies to assess for cross-reactivity and specificity., Results: Following acute infections, all antibody classes rose in the majority of but not in all patients, followed by decreasing titres that did not return to baseline levels. Sixteen per cent of enteritis cases did not demonstrate a rise in titres and 9% of cases had significant levels of antibodies >20 months post-infection. The ELISA used was shown to be highly specific for the detection of Campylobacter antibodies., Conclusion: The use of Campylobacter-specific antibody levels as the sole marker of prior infection is an unreliable method of determining the association between Campylobacter infection and neurological disease.

Routine analytical means to estimate Campylobacter numbers per milliliter of carcass rinses are needed in high-sample-throughput poultry laboratories. We compared three serological confirmatory tests that were amenable to such a setting when used in conjunction with Campy-Line and Campy-Cefex Campylobacter selective agars. Pre- and post-chlorinated chiller carcass rinse samples were obtained and held on ice, then analyzed 24 h later in two separate laboratories. Presumptive counts on both pre- and postchiller samples from between laboratories on individual agars and between both agars were highly correlated. Agreement among the three serological tests was nearly complete. The use of a premeasured and dried latex anti-Campylobacter antibody agglutination test format was superior to that of either a liquid latex agglutination format or a direct phosphate-buffer microscopic technique in terms of practicality as was the inclusion of an unarmed latex control to detect auto agglutination. A routine procedure for Campylobacter level estimation was suggested. This procedure, when used in conjunction with a serological confirmatory step, should provide processors with a means to assess reductions in numbers per milliliter of carcass rinses versus strictly presence-absence testing.

Although vaccination, after having been more than 200 years in medical practice, has proven to be the most effective and the cheapest way to prevent infectious diseases, they remain still the main cause of human premature deaths. As many pathogens enter the human body through the mucosal surfaces, the mucosal way of immunization is considered to be the most promising strategy to decrease the number of human infections. Moreover, the oral delivery system eliminates the necessity of injection what is extremely important for pediatric immunization programs. However, most of recently constructed subunit vaccines based on purified bacterial/viral antigens are rather poorly immunogenic. This review presents some novel ways to enhance and modulate host immune responses by combining antigens with specific adjuvants or by employing specific delivery systems. We also discuss some recent technologies, based on mining the genomic sequences of bacterial pathogens, which accelarate and improve identification of new candidates for vaccine construction. As an example, we focus on the progress in the development of vaccine against Campylobacter spp. Campylobacter jejuni is now recognized as a leading cause of bacterial enteritis in human.

A new test system on the basis of magnetoimmunosorbents for the rapid indication of capmpylobacteriosis has been developed. Information on its use under the conditions of emergency situations is presented. Good prospects of this new test system in the study of environmental objects have been demonstrated.

Aim: The aim of this study was to investigate the presence of antigens with immunological cross-reactivity in periodontopathogenic bacteria and Helicobacter pylori, the pathogen associated with gastritis and peptic ulcers in human., Materials and Methods/results: Among the putative periodontopathogens tested (Actinobacillus actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola), cross-reactive bands were only detected in C. rectus by SDS-PAGE/Western immunoblotting analysis using a polyclonal antibody directed to H. pylori cells. One of these cross-reactive antigens, a 64-kDa band antigen, also reacted with a monoclonal antibody directed to the human heat shock protein (HSP) 60. The N-terminal amino acid sequence of this C. rectus protein revealed a high degree of homology with corresponding regions of other HSPs belonging to the HSP60 family, indicating that the 64-kDa antigen was a GroEL protein. The nucleotide sequence of the C. rectus GroEL protein coded for a 547 amino acid protein with a predicted size of 57.8 kDa. Comparison of the alignment of the deduced amino acid sequence of the GroEL protein of C. rectus with that of H. pylori showed a high degree of similarity throughout its length (76.8%). GroEL protein from C. rectus possessed the ability to stimulate production of IL-6 by a confluent monolayer of human gingival epithelial cells and was cytotoxic when used at a high concentration., Conclusions: This study reveals an immunological relationship between H. pylori and C. rectus, and clearly indicates that one of the shared antigens is a GroEL protein possessing a biological activity that might play a role in the initiation and progression of periodontal disease.

Campylobacter rectus, a gram-negative, microaerophilic, and motile bacterium, has been proposed to play a pathogenic role in human periodontitis. Surface components, such as the flagellum, surface layer (S-layer), and cytotoxin, have been reported as possible virulence factors of the microorganism. In the present study, monoclonal antibodies against surface components of this bacterium were produced to detect and investigate the pathogenic potential of C. rectus in periodontitis. Two monoclonal antibodies, designated CRT-1 and CRT-2, recognized a peculiar 150 kDa S-layer protein by immunoblot analysis. The CRT-2 antibody reacted to all C. rectus strains tested, except for the S-layer negative strain of the species [C. rectus ATCC 33238 S-layer (-) strain]. The CRT-3 antibody reacted to a 60-kDa protein in C. rectus and also cross-reacted with Campylobacter showae ATCC 51164 and CCUG 11641 strains. Using the dot-blot method, we were able to detect C. rectus using the CRT-2 antibody when as few as 103 organisms were present in a subgingival dental plaque sample. Detection of C. rectus in plaque samples correlated significantly with clinical findings such as probing depth (P < 0.001), bleeding on probing (P < 0.001), and gingival index (P < 0.001). These findings indicate that infection by C. rectus may be an important indicator of periodontal disease status.

The purpose of this study was to clarify the antigenic properties of the GroEL-like protein of Campylobacter rectus using a specific polyclonal antibody directed to the purified 64-kDa GroEL-like protein (pAb-CrGroEL), a polyclonal antibody directed to the Actinobacillus actinomycetemcomitans GroEL-like protein (pAb-AaGroEL) and a monoclonal antibody against the recombinant human HSP60 (mAb-HuHSP60). In SDS-PAGE/Western immunoblotting analysis, mAb-HuHSP60, pAb-CrGroEL and pAb-AaGroEL were found to react with the GroEL-like protein (64-kDa) present in all C. rectus strains. A 150-kDa protein in C. rectus ATCC 33238 also reacted strongly with pAb-CrGroEL. This 150-kDa protein was found to be present on the surface-associated material of bacterial cells, as determined by transmission electron microscopy and immunogold labelling of cells with pAb-CrGroEL. Analysis of the first 20 N-terminal amino acids of the sequence of the 150-kDa protein revealed a strong homology (80%) with the C. rectus surface layer (S-layer) protein. Investigation of the biochemical nature of antigenic determinants using periodic acid and proteolytic enzymes showed that the C. rectus GroEL-like protein possessed immunodominant epitopes in both peptide and carbohydrate chains, and that the immunoreactive determinants of the 150-kDa protein belonged to carbohydrate. These results suggest that the GroEL-like protein and the S-layer protein of C. rectus may share the same carbohydrate epitopes.

Aims: To investigate the occurrence and numbers of thermophilic campylobacters excreted by cattle in dairy herds, and to assess the strain diversity within herds., Methods and Results: Faecal samples from 15 animals at each of 24 cattle farms were cultured quantitatively for thermophilic campylobacters and 23% of animals and 83% of farms were positive for Campylobacter jejuni. Young animals had a higher prevalence and higher faecal concentration than older animals. Serotyping and pulsed field gel electrophoresis (PFGE) of isolates showed that the most common serotypes were 2, 4-complex and 11. Serotype 2 was especially prevalent among calves (68% of the positive calves). In eight of the 20 positive herds, all isolates had the same sero- and PFGE type while, in the other herds, two to five different types were isolated., Conclusions: Significant differences were found between age groups in relation to the prevalence and numbers of excreted campylobacters, serotype distribution and strain diversity. The relatively few different strains in each herd indicate that transmission between animals is common., Significance and Impact of the Study: The high prevalence on cattle farms of the human pathogen C. jejuni and the wide distribution of serotype 2, the most common serotype among Danish patients, indicate that cattle might be an important reservoir for human infections. The ability of this serotype to colonize calves in high numbers further indicates that serotype 2 strains may have an advantage over other serotypes.