Campylobacter Concisus Research Articles

The susceptibility of Campylobacter concisus to the bactericidal effects of normal human serum.

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 48hours. 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 30min. 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.

Current roles of specific bacteria in the pathogenesis of inflammatory bowel disease

The relevance of alterations in gut microbiota in the pathogenesis of inflammatory bowel disease (IBD) remains unclear. Currently there is conflicting evidence with regards to the roles of specific bacterial species. <em>Escherichia coli </em>(particularly the adherent invasive strain) are more prevalent in those with IBD and are associated with higher risk of IBD. However, the organisms are also present in healthy individuals and colonisation does not correlate with the degree of inflammation in IBD. <em>Campylobacter concisus</em> is more prevalent in those with IBD and higher levels of <em>C. concisus</em> specific IgG antibodies are found in the serum of those with IBD compared to healthy controls. Further, <em>C. concisus</em> has immunogenic properties that stimulate an antibody response suggesting the bacteria might trigger or exacerbate disease. Conversely most mycobacteria are unlikely to be causative as they are not presentin microbial stool cultures early in disease. In various studies,<em>Mycobacterium aviumparatuberculosis</em>has been detected both more frequently and not at all in individuals with Crohn's disease. Similar conflict exists with respect to <em>Yersinia enterocolitica,Bacteroidesvulgatus</em> and <em>Helicobacter hepaticus</em>, which are also more prevalent in IBD. However, these organisms appear more likely to contribute to disease persistence than initial disease development. This review aims to summarise the current understanding of key bacterial species implicated in the pathogenesis of IBD.

Campylobacter concisus pseudo-outbreak caused by improved culture conditions.

An unusual increase in the number of Campylobacter concisus isolates found in stool cultures provoked an outbreak investigation at Bern University Hospital. No epidemiological links were found between the cases, and the Campylobacter isolates were clonally unrelated. A change in culture conditions to a hydrogen-rich atmosphere enhancing growth of C. concisus was deemed responsible for this pseudo-outbreak.

Role of Emerging Campylobacter Species in Inflammatory Bowel Diseases

The gut microbiota is a central player in the etiology of inflammatory bowel diseases. As such, there is intense scientific interest in elucidating the specific group/s of bacteria responsible for driving barrier damage and perpetuating the chronic inflammation that results in disease. Because of their ability to colonize close to the surface of the host intestinal epithelium, mucosa-associated bacteria are considered key players in the initiation and development of both Crohn's disease and ulcerative colitis. The leading bacterial candidates include adherent and invasive Escherichia coli, Helicobacter, Fusobacteria, Mycobacteria, and Campylobacter species. Of these, a member of the Campylobacter genus, Campylobacter concisus, has recently emerged as a putative player in the pathogenesis of inflammatory bowel diseases. Current research indicates that this bacterium possesses extraordinarily diverse pathogenic capacities as well as unique genetic and functional signatures that are defined by their ability to adhere to and invade host cells, secrete toxins, and the presence of a virulence-associated restriction-modification system. These characteristics enable the potential classification of C. concisus into distinct pathotypes, which we have named adherent and invasive C. concisus and adherent and toxinogenic C. concisus. In this review, we evaluate evidence for the role of emerging Campylobacter species in the pathogenesis of inflammatory bowel diseases.

Modelling the thermal inactivation of five Campylobacteraceae species

Abstract This study investigated the thermal inactivation of five Campylobacteraceae species (Campylobacter coli, Campylobacter helveticus, Campylobacter concisus, Campylobacter fetus subsp. fetus and Arcobacter butzleri) at 55 and 60 °C using an immersed coil heating apparatus. The applicability of nine different models, including log linear and Weibull type models, some of which accounted for shoulders and tailing populations at the start or end of the heat treatment, was assessed to describe the thermal inactivation of each species. The Weibull model with tailing effect provided a good fit with low RMSE value (0.07–0.27), AICc (−88.12 to −6.82) and high R2 values (0.97–0.99) depending on the temperature and the species. The Weibull + tail model showed a significantly high D value for Arcobacter butzerli (180.2 s) at 55 °C and a low D value for C. helveticus (23.9 s) at 60 °C, with a high degree of variability in thermal tolerance noted across the species. Moreover, the Weibull + tail model also indicated high thermal sensitivity for C. fetus subsp. fetus at both temperatures investigated. This study highlights the value of assessing various inactivation models to describe the D value to get the model which best describes the survival data. These model predictions enhance knowledge about the survival characteristics and behaviour of fastidious Campylobacteraceae in the food chain.

The interplay between Campylobacter and Helicobacter species and other gastrointestinal microbiota of commercial broiler chickens.

BackgroundPoultry represent an important source of foodborne enteropathogens, in particular thermophilic Campylobacter species. Many of these organisms colonize the intestinal tract of broiler chickens as harmless commensals, and therefore, often remain undetected prior to slaughter. The exact reasons for the lack of clinical disease are unknown, but analysis of the gastrointestinal microbiota of broiler chickens may improve our understanding of the microbial interactions with the host.MethodsIn this study, the fecal microbiota of 31 market-age (56-day old) broiler chickens, from two different farms, was analyzed using high throughput sequencing. The samples were then screened for two emerging human pathogens, Campylobacter concisus and Helicobacter pullorum, using species-specific PCR.ResultsThe gastrointestinal microbiota of chickens was classified into four potential enterotypes, similar to that of humans, where three enterotypes have been identified. The results indicated that variations between farms may have contributed to differences in the microbiota, though each of the four enterotypes were found in both farms suggesting that these groupings did not occur by chance. In addition to the identification of Campylobacter jejuni subspecies doylei and the emerging species, C. concisus, C. upsaliensis and H. pullorum, several differences in the prevalence of human pathogens within these enterotypes were observed. Further analysis revealed microbial taxa with the potential to increase the likelihood of colonization by a number of these pathogens, including C. jejuni.ConclusionDepletion of these taxa and the addition of taxa that compete with these pathogens, may form the basis of competitive exclusion strategies to eliminate them from the gastrointestinal tract of chickens.

The Association Between Detectable Plasmatic Human Immunodeficiency Virus (HIV) Viral Load and Different Subgingival Microorganisms in Brazilian Adults With HIV: A Multilevel Analysis

This study investigates the association between detectable plasmatic human immunodeficiency virus (HIV) viral load (HVL) and high levels of periodontal- and non-periodontal-related microorganisms in the subgingival microbiota of individuals with HIV. Thirty-seven individuals with HIV were divided into two groups: 1) detectable HVL (n = 15); and 2) undetectable HVL (n = 22). Subgingival biofilm samples were obtained, and the levels of 35 microbial species were determined by the checkerboard DNA-DNA hybridization method. Periodontal clinical measures and laboratory and sociodemographic data were also registered. χ(2) test, Fisher exact test, and Mann-Whitney U test were used to compare groups. Multilevel ordinal regression models were used to test the association between HVL and the levels of 35 microbial species in subgingival biofilm, adjusted for confounders. Of the 35 species studied, 11 (31.4%) showed higher mean levels in the detectable HVL group than undetectable HVL group (P <0.001). These species included Actinomyces naeslundii II, Actinomyces israelii, Actinomyces odontolyticus, Veillonella parvula, Capnocytophaga gingivalis, Eikenella corrodens, Campylobacter concisus, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Candida albicans. Significant associations between detectable HVL and high levels of microorganisms, adjusted for confounders, were observed for A. naeslundii I, Actinomyces gerencseriae, C. gingivalis, E. corrodens, C. concisus, Prevotella nigrescens, T. forsythia, and Dialister pneumosintes. Detectable plasmatic HVL in individuals with HIV was associated with elevated levels of known periodontal pathogens, such as P. nigrescens, T. forsythia, and E. corrodens, as well as C. concisus, C. gingivalis, and D. pneumosintes in the subgingival biofilm.

Psychometric scores and persistence of irritable bowel after Campylobacter concisus infection

Objective. Gastroenteritis with Campylobacter concisus is an emerging infection, but the risk of irritable bowel syndrome (IBS) following it is unknown. Material and methods. In a prospective, community-based study of gastroenteritis with C. concisus and C. jejuni/coli, we invited adult patients to participate in a questionnaire study, including IBS symptoms and psychometric scores, at baseline and at 6 months. We estimated adjusted RR (RRadj) (for age, sex and comorbidity) for IBS as the primary outcome. Results. The development of IBS symptoms at 6 months was reported in 26/106 (25%) patients with C. concisus infection, and in 30/162 (19%) of C. jejuni/coli patients. The baseline predictors for IBS in C. concisus infection were high anxiety scores (RRadj 2.0; 95% CI 1.1–3.6, p < 0.05), chills (RRadj 1.9; 95% CI 1.0–3.6, p < 0.05), headache (RRadj 2.5; 95% CI 1.1–6.0, p < 0.05), dizziness (RRadj 2.6; 95% CI 1.2–5.8, p < 0.05) and muscle ache (RRadj 3.6; 95% CI 1.4–8.9, p < 0.01). For all Campylobacter patients (n = 268), we confirmed previous reports of anxiety (RRadj 2.0; 95% CI 1.3–3.1), depression (RRadj 2.3; 95% CI 1.3–4.0) and high somatization scores (RRadj 3.0; 95% CI 1.5–6.0) as predictors for post-infectious IBS (PI-IBS). Conclusions. Gastroenteritis with C. concisus carries a 25% risk of IBS at 6-month follow-up. The risk factors for IBS are chills, headache, dizziness and muscle ache in the acute stage, as well as preexisting high psychometric scores for anxiety. Our findings suggest that psychological factors play a role in the development of PI-IBS.

The role of autophagy in the intracellular survival of Campylobacter concisus

Campylobacter concisus is an emerging pathogen that has been associated with gastrointestinal diseases. Given the importance of autophagy for the elimination of intracellular bacteria and the subversion of this process by pathogenic bacteria, we investigated the role of autophagy in C. concisus intracellular survival. Gentamicin protection assays were employed to assess intracellular levels of C. concisus within Caco-2 cells, following autophagy induction and inhibition. To assess the interaction between C. concisus and autophagosomes, confocal microscopy, scanning electron microscopy, and transmission electron microscopy were employed. Expression levels of 84 genes involved in the autophagy process were measured using qPCR. Autophagy inhibition resulted in two- to four-fold increases in intracellular levels of C. concisus within Caco-2 cells, while autophagy induction resulted in a significant reduction in intracellular levels or bacterial clearance. C. concisus strains with low intracellular survival levels showed a dramatic increase in these levels upon autophagy inhibition. Confocal microscopy showed co-localization of the bacterium with autophagosomes, while transmission electron microscopy identified intracellular bacteria persisting within autophagic vesicles. Further, qPCR showed that following infection, 13 genes involved in the autophagy process were significantly regulated, and a further five showed borderline results, with an overall indication towards a dampening effect exerted by the bacterium on this process. Our data collectively indicates that while autophagy is important for the clearance of C. concisus, some strains may manipulate this process to benefit their intracellular survival.

Campylobacter concisusand inflammatory bowel disease

Investigation of the possible role of Campylobacter concisus (C. concisus) in inflammatory bowel disease (IBD) is an emerging research area. Despite the association found between C. concisus and IBD, it has been difficult to explain how C. concisus, a bacterium that is commonly present in the human oral cavity, may contribute to the development of enteric diseases. The evidence presented in this review shows that some C. concisus strains in the oral cavity acquired zonula occludens toxin (zot) gene from a virus (prophage) and that C. concisus Zot shares conserved motifs with both Vibrio cholerae Zot receptor binding domain and human zonulin receptor binding domain. Both Vibrio cholerae Zot and human zonulin are known to increase intestinal permeability by affecting the tight junctions. Increased intestinal permeability is a feature of IBD. Based on these data, we propose that a primary barrier function defect caused by C. concisus Zot is a mechanism by which zot-positive C. concisus strains may trigger the onset and relapse of IBD.

Development and Evaluation of a Multiplex PCR for the Detection of Campylobacter concisus and Other Campylobacter spp. from Gastroenteritis Cases

We developed and evaluated a multiplex PCR (m-PCR) for application in routine diagnostic laboratories to detect Campylobacter spp. in stool samples including C. concisus, C. jejuni, and C. coli. When this m-PCR was applied on spiked faecal samples, C. concisus, C. jejuni, and C. coli were specifically identified at 105 cells/gm of faeces. To compare the sensitivity of the m-PCR with conventional culture techniques, the same spiked stool samples were cultured on an antibiotic free Columbia blood agar using the filtration technique. The detection limit of conventional culture method was 105 cells/gm of stool for C. concisus and 106 cells/gm of stool for C. jejuni and C. coli. The m-PCR was applied to test 127 faecal samples from children with gastroenteritis and the results were compared with the conventional bacterial cultures data. By this m-PCR technique, C. jejuni was detected in 7 samples, C. coli in 2 samples, and C. concisus in 7 samples. However, the conventional culture results for these samples were 6 for C. jejuni, 2 for C. coli and only one sample was positive for C. concisus. In total, 19 samples were positive for Campylobacter spp. by m-PCR while only 9 samples were positive for Campylobacter spp. by culture. In conclusion, m-PCR is more sensitive than the culture technique to detect C. concisus and other fastidious campylobacters in faeces.

Molecular diagnosis of Arcobacter and Campylobacter in diarrhoeal samples among Portuguese patients

The present study was conducted to investigate the prevalence and diversity of Arcobacter and Campylobacter spp. in 298 stool samples of patients with diarrhoea, collected from 22 Portuguese hospitals, between September and November 2012. Detection of Arcobacter and Campylobacter spp. was performed using molecular-based detection techniques, such as real-time fluorescence resonance energy transfer PCR, species-specific PCR, and sequencing of amplified PCR products. Overall, 1.3% of the samples were positive for Arcobacter butzleri and 0.3% for Arcobacter cryaerophilus. Campylobacter spp. were found in 31.9% of diarrhoeic faeces. Campylobacter jejuni and Campylobacter concisus were the most prevalent species (13.7% and 8.0%, respectively). The prevalence of Arcobacter and Campylobacter spp. was significantly different between children and adults (39.7% versus 22.8%, P = 0.003). We underline the high prevalence of these pathogens in diarrhoeal samples among Portuguese patients, with particular relevance in the paediatric age group.

Tools to Covisualize and Coanalyze Proteomic Data with Genomes and Transcriptomes: Validation of Genes and Alternative mRNA Splicing

Direct links between proteomic and genomic/transcriptomic data are not frequently made, partly because of lack of appropriate bioinformatics tools. To help address this, we have developed the PG Nexus pipeline. The PG Nexus allows users to covisualize peptides in the context of genomes or genomic contigs, along with RNA-seq reads. This is done in the Integrated Genome Viewer (IGV). A Results Analyzer reports the precise base position where LC-MS/MS-derived peptides cover genes or gene isoforms, on the chromosomes or contigs where this occurs. In prokaryotes, the PG Nexus pipeline facilitates the validation of genes, where annotation or gene prediction is available, or the discovery of genes using a "virtual protein"-based unbiased approach. We illustrate this with a comprehensive proteogenomics analysis of two strains of Campylobacter concisus . For higher eukaryotes, the PG Nexus facilitates gene validation and supports the identification of mRNA splice junction boundaries and splice variants that are protein-coding. This is illustrated with an analysis of splice junctions covered by human phosphopeptides, and other examples of relevance to the Chromosome-Centric Human Proteome Project. The PG Nexus is open-source and available from https://github.com/IntersectAustralia/ap11_Samifier. It has been integrated into Galaxy and made available in the Galaxy tool shed.

Clinical Manifestations of Campylobacter concisus Infection in Children

There is only sparse information about the clinical impact of Campylobacter concisus infections in children. A study was performed during a 2-year period to determine the clinical manifestations in C. concisus-positive children with gastroenteritis. A case patient was defined as a child or teenager (<18 years) with a C. concisus-positive stool sample during the study period. Clinical data were obtained with use of a questionnaire study supplemented with the patients' medical records. The clinical manifestations in these patients were compared with those of patients with Campylobacter jejuni/coli infection. Two thousand three hundred seventy-two diarrheic stool samples from 1867 children were cultured for pathogenic enteric bacteria during the study period, and 85 and 109 children with C. concisus and C. jejuni/coli, respectively, were identified. Comparison of the acute clinical manifestations in 44 C. concisus patients with those in 64 C. jejuni/coli patients showed a significantly lower prevalence of fever, chills and blood in stools in the former. However, half of C. concisus patients compared with one-fourth of C. jejuni/coli patients had prolonged diarrhea for more than 2 weeks and two-thirds of all children with C. concisus reported loose stools after 6-month follow-up. C. concisus infection in children seems to have a milder course of acute gastroenteritis compared with C. jejuni/coli infection but is associated with more prolonged diarrhea. Children with C. concisus have the same degree of late gastrointestinal complaints as children diagnosed with C. jejuni/coli infection.

Campylobacter concisus and exotoxin 9 levels in paediatric patients with Crohn’s disease and their association with the intestinal microbiota

There is mounting evidence for a possible role for Campylobacter concisus in Crohn's disease (CD). However, the pathogenic potential of C. concisus remains disputed due to its presence in healthy subjects. It is documented that genetic diversity exists within this species, with some strains possessing putative virulence determinants such as exotoxin 9/DnaI that may enable them to persist intracellularly in host cells. In order to clarify this, we employed real-time PCR to determine C. concisus and exotoxin 9 levels within faecal samples of CD patients and healthy controls, and correlated these levels with abundances of microbial taxa identified in a subset of subjects. Both C. concisus and exotoxin 9 levels were found to be higher in CD patients than healthy controls, suggesting not only that CD patients had a greater abundance of C. concisus but also that their strains were likely to be more virulent. Moreover, C. concisus levels correlated with the exotoxin 9 levels in CD patients but not in healthy controls, indicating that healthy controls were colonized by non-virulent C. concisus strains. Correlations with the intestinal microbiota found C. concisus levels to correlate with Eubacterium, Subdoligranulum and Blautia, while exotoxin 9 levels correlated with Dialister, Oscillospira, Lachnospira and Prevotella. This suggests that either the composition of the intestinal microbial flora has the ability to influence levels of both virulent and non-virulent C. concisus strains, or infection with C. concisus may modulate the levels of specific bacterial taxa within the gastrointestinal tract.

The Role of Epsilonproteobacteria in Children With Gastroenteritis

A polymerase chain reaction-denaturing gradient gel electrophoresis method was used to examine 50 stool samples from children in Belgium with gastroenteritis for an extensive range of Epsilonproteobacteria species. During the 3-month study period, Campylobacter concisus was the most common species. Our observations suggest that C. concisus displays similar microbiologic and clinical features as Campylobacter jejuni.

The Prevalence and Polymorphisms of Zonula Occluden Toxin Gene in Multiple Campylobacter concisus Strains Isolated from Saliva of Patients with Inflammatory Bowel Disease and Controls

Campylobacter concisus is an oral bacterium. A number of studies detected a significantly higher prevalence of C . concisus in the intestinal tract of patients with inflammatory bowel disease (IBD) as compared to controls. The prevalence of zonula occluden toxin (zot) gene, which encodes a toxin known to increase intestinal permeability, in oral C . concisus strains is unknown. Increased intestinal permeability is a feature of IBD. A total of 56 oral C . concisus strains isolated from 19 patients with IBD and 20 controls were examined (some individuals were colonized with multiple strains). A filtration method was used for isolation of C . concisus from saliva samples. SDS-PAGE was used to define strains. PCR was used to amplify zot from C . concisus strains. Positive PCR products were sequenced and the nucleotides and amino acids were compared. Of the 56 oral C . concisus strains examined, 17 strains (30.4%) were positive for zot. The prevalence of zot-positive oral C . concisus strains was 54.5% in patients with active IBD, which was not significantly different from that in healthy controls (40%). Polymorphisms of C . concisus zot were revealed. zot 808T , zot 350-351AC and zot Multiple were detected only in patients with IBD, but not in healthy controls. Both zot 808T and zot Multiple alleles resulted in substitution of valine at position 270, which occurred in 36.4% of patients with active IBD but not in healthy controls (P = 0.011). Furthermore, the prevalence of multiple oral C . concisus strains in patients with active IBD was significantly higher than that in healthy controls (P = 0.013). This is the first study reporting the prevalence of zot in human oral C . concisus strains and the polymorphisms of C . concisus zot gene. The data suggest that the possible role of C . concisus strains containing specific polymorphic forms of zot gene in human IBD should be investigated.

Comparative genomics of Campylobacter concisus isolates reveals genetic diversity and provides insights into disease association

BackgroundIn spite of its association with gastroenteritis and inflammatory bowel diseases, the isolation of Campylobacter concisus from both diseased and healthy individuals has led to controversy regarding its role as an intestinal pathogen. One proposed reason for this is the presence of high genetic diversity among the genomes of C. concisus strains.ResultsIn this study the genomes of six C. concisus strains were sequenced, assembled and annotated including two strains isolated from Crohn’s disease patients (UNSW2 and UNSW3), three from gastroenteritis patients (UNSW1, UNSWCS and ATCC 51562) and one from a healthy individual (ATCC 51561). The genomes of C. concisus BAA-1457 and UNSWCD, available from NCBI, were included in subsequent comparative genomic analyses. The Pan and Core genomes for the sequenced C. concisus strains consisted of 3254 and 1556 protein coding genes, respectively.ConclusionGenes were identified with specific conservation in C. concisus strains grouped by phenotypes such as invasiveness, adherence, motility and diseased states. Phylogenetic trees based on ribosomal RNA sequences and concatenated host-related pathways for the eight C. concisus strains were generated using the neighbor-joining method, of which the 16S rRNA gene and peptidoglycan biosynthesis grouped the C. concisus strains according to their pathogenic phenotypes. Furthermore, 25 non-synonymous amino acid changes with 14 affecting functional domains, were identified within proteins of conserved host-related pathways, which had possible associations with the pathogenic potential of C. concisus strains. Finally, the genomes of the eight C. concisus strains were compared to the nine available genomes of the well-established pathogen Campylobacter jejuni, which identified several important differences in the respiration pathways of these two species. Our findings indicate that C. concisus strains are genetically diverse, and suggest the genomes of this bacterium contain respiration pathways and modifications in the peptidoglycan layer that may play an important role in its virulence.

Functional relationship between Campylobacter concisus and the stomach ecosystem in health and disease

Functional relationship between Campylobacter concisus and the stomach ecosystem in health and disease

Neutrophil activation by Campylobacter concisus

BackgroundCampylobacter concisus is an emerging enteric pathogen associated with prolonged diarrhoea and possibly inflammatory bowel disease in children as well as adults, but the interaction with cells of the innate immune system is unclear. The magnitude of systemic immunoglobulin response in acute infection is unknown.MethodsNeutrophils from healthy volunteers were activated with five faecal isolates of C. concisus from patients with gastroenteritis as well as the oral reference strain C. concisus ATCC33237. Neutrophils were tested for the expression of adherence molecule CD11b by immunoflourescence and for oxidative burst response by chemiluminescence. The opsonic activity in a chemiluminescence assay was assessed with heat treated serum from patients with C. concisus infection.ResultsA strong and dose-dependent activation of neutrophil adherence molecule CD11b and oxidative burst response was demonstrated with all six C. concisus isolates. Bacteria opsonised in heat treated serum induced an increased chemiluminescence response. Heat treated serum from patients with C. concisus infection did not have a higher opsonic activity than heat treated serum from healthy volunteers.ConclusionC. concisus has the capability to activate the innate immune system by stimulating neutrophil cells to increased adherence molecule expression and oxidative burst response, both crucial for acute inflammation. In a chemiluminescence assay the opsonic activity of heat treated serum from patients was not increased compared to heat treated control serum suggesting a weak systemic IgG response to infection.