High incidence of Campylobacter concisus in gastroenteritis in North Jutland, Denmark: a population-based study

Assessing the Prevalence and Dynamics of Emerging Campylobacterales in Human Stool Samples in Brussels by Filtration Culture

Thermophilic C. jejuni/coli is reported to be the first bacterial cause of gastroenteritis worldwide and the most common zoonosis in Europe. Although non-jejuni/coli Campylobacter sp. are increasingly suspected to be responsible for diarrhoea or to be involved in inflammatory bowel disease, they remain poorly isolated due to their fastidious and non-thermophilic nature. Additionally, they are not targeted by commercial syndromic PCR assays. In this study, we present routine diagnostic results over 6 years (2017-2019 and 2021-2023) of Campylobacter sp. and related species, obtained by optimised culture from 51,065 stools by both 0.65 µm pore filtration on antibiotic-free agar, incubated in an H2-enriched atmosphere at 37 °C (also known as the Cape Town protocol), and the use of selective inhibitory Butzler medium incubated at 42 °C. This allowed the isolation of 16 Campylobacter species, 2 Aliarcobacter species, and 2 Helicobacter species, providing a completely different view of the epidemiology of Campylobacterales, in which C. jejuni/coli represents only 30.0% of all isolates, while C. concisus represents 44.4%. C. ureolyticus, representing only 5.5% of all Campylobacterales pre-COVID-19, represented 20.6% of all strains post-COVID-19 (218% increase; p < 0.05). At the same time, the proportions of C. jejuni, C. coli, and C. concisus decreased by 37, 53, and 28%, respectively (p < 0.05).

Antimicrobial Susceptibility Patterns and Genetic Diversity of Campylobacter spp. Isolates from Patients with Diarrhea in South Korea

This study aimed to characterize the latest antimicrobial resistance patterns and genetic diversity of Campylobacter spp. isolated from patients with acute diarrhea in Korea. In total, 371 clinical isolates (361 Campylobacter jejuni and 10 Campylobacter coli) were collected from patients with diarrhea in 106 medical institutions of six provinces during the seasonal peak (April-September 2022) in South Korea. We then assessed their antimicrobial susceptibility to eight antimicrobial agents and performed multilocus sequence typing (MLST). This study investigated the antimicrobial resistance (AMR) profiles to tetracycline (32.3%), nalidixic acid (64.9%), and ciprofloxacin (83.3%), confirming high levels of the latter even after its Korean ban in 2010. However, tetracycline resistance displayed a decreasing trend. Alternatively, significantly lower resistance rates to clindamycin (0.8%), azithromycin (0.53%), erythromycin (0.53%), and gentamicin (0.53%) as well as absolute susceptibility to florfenicol (0%) were observed. Four C. jejuni and three C. coli isolates (7/371, 1.88%) were classified as multidrug-resistant (MDR) to at least three antimicrobial classes. MLST identified a high genetic diversity with 21 clonal complexes (CCs) and sixty-six sequence types (STs), including eight novel STs. The high CC frequency of C. jejuni comprised CC21 (37.7%), CC22 (13.8%), and CC206 (9.4%), while C. coli was predominated by CC828 (90%). The high CC21 and CC828 strain prevalence in this study was consistent with their worldwide distribution. This study highlights that quinolone- and tetracycline-resistant Campylobacter circulate in Korea with diverse genotypes, providing important information that could contribute to controlling and preventing increasing antimicrobial resistance in patients.

Investigating the Significance of Non-jejuni/coli Campylobacter Strains in Patients with Diarrhea

Campylobacter is one of the most commonly reported foodborne bacteria worldwide. Although Campylobacter jejuni and Campylobacter coli have been reported to be responsible for the great majority of campylobacteriosis, the burden of infections by species other than C. jejuni and C. coli have been increasing as a result of a transition to diagnostic test methods that enable the isolation of emerging species. The aim of the present study was to recover C. jejuni, C. coli, and emerging species from the stool samples of 500 patients with gastroenteritis and 100 healthy subjects via the use of a filtration method and culture techniques using Butzler agar and mCCDA under a microaerobic or hydrogen-enriched atmosphere, identify the species by multiplex PCR methods and assess the significance of emerging species in enteric diseases. Thirty-one (6.2%) Campylobacter spp. were isolated from the stool samples of diarrheic patients but none from healthy individuals. Of 31 isolates, 21 (67.8%), nine (29%), and one (3.2%) were identified as C. jejuni, C. coli, and Campylobacter concisus by multiplex PCR, respectively. The filtration method was superior to the culture technique using mCCDA under a microaerobic atmosphere. C. concisus was evaluated as the etiology of gastroenteritis as a result of laboratory and clinical evaluations. The present study was the first to indicate that emerging Campylobacter species are rarely detected and C. concisus is linked to acute gastroenteritis in Turkey where additional studies are warranted to clarify the significance of emerging species in gastroenteritis.

An integrated computational approach to infer therapeutic targets from Campylobacter concisus and peptidomimetic based inhibition of its pyrimidine metabolism pathway

Campylobacter concisus is a commensal of the human oral flora that has been allied with persistent diarrhea and inflammatory bowel disease (IBD). In children under the age of two, Campylobacter infections are common in the developing countries and have frequently been associated with mortality. They are becoming a prevalent cause of bacterial diarrhea in early adulthood in developed countries as well. The need for identifying new therapeutic targets and drugs is crucial for curbing such infections. Therefore, we identified 18 cytoplasmic potential therapeutic candidates against the type strain of C. concisus and deoxycytidine triphosphate deaminase (dCTP deaminase), involved in pyrimidine synthesis was selected for screening of peptidomimetic inhibitors (n > 30,000 peptidomimetics) against it. To the best of our knowledge, this target has not been studied for Campylobacter spp. Three potent inhibitors of this enzyme were prioritized i.e. peptidomimetic 27, 64, and 150. Dynamics simulation of 100 ns was carried out to validate findings for top-scored inhibitors along with physiology-based pharmacokinetics to estimate behavior in human body and predict dosing parameters. This verification demonstrates a first-in-human pharmacokinetic simulation for these peptidomimetics and can help enhance confidence in these peptide-like structures. Moiety 27 (IUPAC name: 5-[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]-N-{[2-(2-methoxyethyl)-1-oxo-1H,2H,3H,4H-pyrrolo[1,2-a]pyrazin-3-yl]methyl}furan-2-carboxamide), 64 (IUPAC name: 3-(2-methylpropyl)-1-{3-[5-(5-oxo-1-phenylpyrrolidin-3-yl)-1,2,4-oxadiazol-3-yl]phenyl}urea), and 150 (IUPAC name: N-(3-methoxypropyl)-1-[6-(4-methylphenyl)-4H,6H,7H-[1,2,3]triazolo[4,3-c][1,4]oxazine-3-carbonyl]piperidine-4-carboxamide) were identified as potent inhibitors of C. concisus.Communicated by Ramaswamy H. Sarma.

The oral microbiome in autoimmune diseases: friend or foe?

The human body is colonized by abundant and diverse microorganisms, collectively known as the microbiome. The oral cavity has more than 700 species of bacteria and consists of unique microbiome niches on mucosal surfaces, on tooth hard tissue, and in saliva. The homeostatic balance between the oral microbiota and the immune system plays an indispensable role in maintaining the well-being and health status of the human host. Growing evidence has demonstrated that oral microbiota dysbiosis is actively involved in regulating the initiation and progression of an array of autoimmune diseases.Oral microbiota dysbiosis is driven by multiple factors, such as host genetic factors, dietary habits, stress, smoking, administration of antibiotics, tissue injury and infection. The dysregulation in the oral microbiome plays a crucial role in triggering and promoting autoimmune diseases via several mechanisms, including microbial translocation, molecular mimicry, autoantigen overproduction, and amplification of autoimmune responses by cytokines. Good oral hygiene behaviors, low carbohydrate diets, healthy lifestyles, usage of prebiotics, probiotics or synbiotics, oral microbiota transplantation and nanomedicine-based therapeutics are promising avenues for maintaining a balanced oral microbiome and treating oral microbiota-mediated autoimmune diseases. Thus, a comprehensive understanding of the relationship between oral microbiota dysbiosis and autoimmune diseases is critical for providing novel insights into the development of oral microbiota-based therapeutic approaches for combating these refractory diseases.

Campylobacter concisus from chronic inflammatory bowel diseases stimulates IL-8 production in HT-29 cells

The emerging pathogen Campylobacter concisus has been isolated from patients with gastrointestinal diseases; however, it is also present in the gut of healthy individuals. The aim of this study was to compare IL-8 production in HT-29 cells after infection with C. concisus from different gastrointestinal disease phenotypes. Additionally, to investigate whether differentiation of isolates in genomospecies (GS1 and GS2) or presence of the zot gene, encoding the Zot toxin, affects IL-8 production. A total of 37 C. concisus isolates from patients with microscopic colitis (n = 20), ulcerative colitis (n = 5), Crohn's disease (n = 5), diarrhoea (n = 2) and from healthy controls (n = 5) were used. Intestinal HT-29 cells were infected and incubated for 24 h. Supernatants were subsequently removed and analysed for IL-8 by MILLIPLEX. All isolates were able to stimulate IL-8 production and IL-8 levels were higher than in non-infected HT-29 cells. No difference was observed between disease phenotypes or GS1 and GS2, whereas presence of the zot gene showed a tendency towards higher IL-8 production. Further investigations in other inflammatory and physiological models are needed to conclude whether C. concisus strains from different gastrointestinal disease phenotypes differ in pathogenic potential and play a part in gastrointestinal disease.

Quantitative detection and genetic characterization of thermotolerant Campylobacter spp. in fresh chicken meats at retail in Japan

Campylobacter jejuni and C. coli are one of the leading causes of gastrointestinal illnesses, and which are considered to be transmitted to humans mainly from chicken meats. Considering the less availability of quantitative contamination data in the retail chicken meats in Japan, 510 fresh chicken meats retailed at five distinct regions in Japan between June 2019 and March 2021 were examined. The quantitative testing resulted that 45.7% of the samples (254/510) were positive at mean ± standard deviation of 1.15 ± 1.03 logCFU/g, whereas 43 samples (8.4%) exceeded 3.0 logCFU/g. Seasonal comparison revealed increased bacterial counts in fall compared with spring and summer. As for the chicken slaughter age, those slaughtered at >75 days old were less contaminated than those at <75 days old. Genome sequencing analyses of 111 representative C. jejuni isolates resulted in the detection of three antimicrobial resistance genes (gyrA substitution T86I, tetO and blaOXA-61) at 25.2, 27.9 and 42.3%, respectively. In silico MLST analysis revealed the predominance of sequence types (ST)-21 clonal complex (CC), followed by ST-45CC and ST-464CC. The single nucleotide polymorphism (SNP)-based phylogenetic tree largely classified the sequenced C. jejuni isolates into two clusters (I and II), where all C. jejuni from highly contaminated samples (STs-21CC, -22CC and -45CC) belonged to cluster I, independent of both season and slaughter age. To our knowledge, this is the first example to study the current status of Campylobacter contamination levels in fresh chicken meats retailed in Japan. Our data would be contributable to future quantitative microbial risk assessment, to establish effective control measures for campylobacteriosis.

Transmission pathways of campylobacter spp. at broiler farms and their environment in Brandenburg, Germany

Broiler meat is widely known as an important source of foodborne Campylobacter jejuni and Campylobacter coli infections in humans. In this study, we thoroughly investigated transmission pathways that may contribute to possible Campylobacter contamination inside and outside broiler houses. For this purpose we carried out a comprehensive longitudinal sampling approach, using a semi-quantitative cultivation method to identify and quantify transmissions and reservoirs of Campylobacter spp.. Three german broiler farms in Brandenburg and their surrounding areas were intensively sampled, from April 2018 until September 2020. Consecutive fattening cycles and intervening downtimes after cleaning and disinfection were systematically sampled in summer and winter. To display the potential phylogeny of barn and environmental isolates, whole genome sequencing (WGS) and bioinformatic analyses were performed. Results obtained in this study showed very high Campylobacter prevalence in 51/76 pooled feces (67.1%) and 49/76 boot swabs (64.5%). Average counts between 6.4 to 8.36 log10MPN/g were detected in pooled feces. In addition, levels of 4.7 and 4.1 log10MPN/g were detected in boot swabs and litter, respectively. Samples from the barn interior showed mean Campyloacter values in swabs from drinkers 2.6 log10MPN/g, walls 2.0 log10MPN/g, troughs 1.7 log10MPN/g, boards 1.6 log10MPN/g, ventilations 0.9 log10MPN/g and 0.7 log10MPN/g for air samples. However, Campylobacter was detected only in 7/456 (1.5%) of the environmental samples (water bodies, puddles or water-filled wheel tracks; average of 0.6 log10MPN/g). Furthermore, WGS showed recurring Campylobacter genotypes over several consecutive fattening periods, indicating that Campylobacter genotypes persist in the environment during downtime periods. However, after cleaning and disinfection of the barns, we were unable to identify potential sources in the broiler houses. Interestingly, alternating Campylobacter genotypes were observed after each fattening period, also indicating sources of contamination from the wider environment outside the farm. Therefore, the results of this study suggest that a potential risk of Campylobacter transmission may originate from present environmental sources (litter and water reservoirs). However, the sources of Campylobacter transmission may vary depending on the operation and farm environmental conditions.

Markers for discriminating Campylobacter concisus genomospecies using MALDI-TOF analysis

Strains identified as Campylobacter concisus may belong to one of at least two biochemically indistinguishable, but genomically distinct, groups referred to as "genomospecies" that may differ in their pathogenic and zoonotic potential. Reliable, affordable and available identification methods are required to improve understanding of their significance in human illness. We examined the potential for MALDI-TOF MS, increasingly used in routine laboratories, for this task. Nineteen well-characterised strains were examined using a widely used MALDI-TOF MS commercial system, however only one strain confidently identified using their database. Data mining of the spectra obtained revealed a number of markers that could be used to help discriminate these genomospecies. We conclude that careful application of MALDI-TOF analysis could be useful to determine the role and significance of diverse C. concisus genomospecies in human disease.

Survival and Control of Campylobacter in Poultry Production Environment

Campylobacter species are Gram-negative, motile, and non-spore-forming bacteria with a unique helical shape that changes to filamentous or coccoid as an adaptive response to environmental stresses. The relatively small genome (1.6 Mbp) of Campylobacter with unique cellular and molecular physiology is only understood to a limited extent. The overall strict requirement of this fastidious microorganism to be either isolated or cultivated in the laboratory settings make itself to appear as a weak survivor and/or an easy target to be inactivated in the surrounding environment of poultry farms, such as soil, water source, dust, surfaces and air. The survival of this obligate microaerobic bacterium from poultry farms to slaughterhouses and the final poultry products indicates that Campylobacter has several adaptive responses and/or environmental niches throughout the poultry production chain. Many of these adaptive responses remain puzzles. No single control method is yet known to fully address Campylobacter contamination in the poultry industry and new intervention strategies are required. The aim of this review article is to discuss the transmission, survival, and adaptation of Campylobacter species in the poultry production environments. Some approved and novel control methods against Campylobacter species throughout the poultry production chain will also be discussed.

Clinical Characteristics, Risk Factors, and Population Attributable Fraction for Campylobacteriosis in a Nicaraguan Birth Cohort

Campylobacteriosis is an important contributor to the global burden of acute gastroenteritis (AGE). In Nicaragua, the burden, risk factors, and species diversity for infant campylobacteriosis are unknown. Between June 2017 and December 2018, we enrolled 444 infants from León, Nicaragua, in a population-based birth cohort, conducting weekly household AGE surveillance. First, we described clinical characteristics of symptomatic Campylobacter infections, and then compared clinical characteristics between Campylobacter jejuni/coli and non-jejuni/coli infections. Next, we conducted a nested case-control analysis to examine campylobacteriosis risk factors. Finally, we estimated the population attributable fraction of campylobacteriosis among infants experiencing AGE. Of 296 AGE episodes in the first year of life, Campylobacter was detected in 59 (20%), 39 were C. jejuni/coli, and 20 were non-jejuni/coli species, including the first report of Campylobacter vulpis infection in humans. Acute gastroenteritis symptoms associated with C. jejuni/coli lasted longer than those attributed to other Campylobacter species. In a conditional logistic regression model, chickens in the home (odds ratio [OR]: 3.8, 95% CI: 1.4-9.8), a prior AGE episode (OR: 3.3; 95% CI: 1.4-7.8), and poverty (OR: 0.4; 95% CI: 0.2-0.9) were independently associated with campylobacteriosis. Comparing 90 infants experiencing AGE with 90 healthy controls, 22.4% (95% CI: 11.2-32.1) of AGE episodes in the first year of life could be attributed to Campylobacter infection. Campylobacter infections contribute substantially to infant AGE in León, Nicaragua, with non-jejuni/coli species frequently detected. Reducing contact with poultry in the home and interventions to prevent all-cause AGE may reduce campylobacteriosis in this setting.

High genetic diversity in Campylobacter concisus isolates from patients with microscopic colitis

The emerging intestinal pathogen Campylobacter concisus has been associated with prolonged diarrhoea and classic inflammatory bowel diseases (IBD) and was recently also linked with microscopic colitis (MC). Previous reports have observed a high genetic diversity within isolates from diarrhoeic and IBD patients and from healthy controls (HC), and division of isolates into two major genomospecies (GS1 and GS2). The aim of this study was to describe genetic diversity in 80 recently cultivated MC biopsy and faecal isolates of C. concisus by multi-locus sequence typing (MLST); and to compare the phylogenetic relatedness to 102 isolates from diarrhoeic and IBD patients and HCs by k-mer-based distance estimation. MLST revealed high genetic diversity in MC isolates with 72 novel sequence types. K-mer divided MC isolates into two distinct clusters (cluster 1 n = 21, cluster 2 n = 49), with a significantly higher prevalence of cluster 2 isolates in biopsies than in faeces, p = 0.009. K-mer divided the 182 isolates into two major phylogenetic clusters: cluster 1 (GS1 isolates) and cluster 2 (GS2 isolates), which further differentiated into three subgroups. Cluster 1 and the three cluster 2 subgroups were each distinctive in mean genome size and GC count. Isolates from all disease phenotypes were present in cluster 1 and cluster 2 subgroup 2 and 3, whereas cluster 2 subgroup 1 only contained isolates restricted to patients with ulcerative colitis (n = 10) and HC (n = 4).

Analysis of complete Campylobacter concisus genomes identifies genomospecies features, secretion systems and novel plasmids and their association with severe ulcerative colitis

Campylobacter concisus is an emerging enteric pathogen that is associated with several gastrointestinal diseases, such as inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC). Currently, only three complete C. concisus genomes are available and more complete C. concisus genomes are needed in order to better understand the genomic features and pathogenicity of this emerging pathogen. DNA extracted from 22 C. concisus strains were subjected to Oxford Nanopore genome sequencing. Complete genome assembly was performed using Nanopore genome data in combination with previously reported short-read Illumina data. Genome features of complete C. concisus genomes were analysed using bioinformatic tools. The enteric disease associations of C. concisus plasmids were examined using 239 C. concisus strains and confirmed using PCRs. Proteomic analysis was used to examine T6SS secreted proteins. We successfully obtained 13 complete C. concisus genomes in this study. Analysis of 16 complete C. concisus genomes (3 from public databases) identified multiple novel plasmids. pSma1 plasmid was found to be associated with severe UC. Sec-SRP, Tat and T6SS were found to be the main secretion systems in C. concisus and proteomic data showed a functional T6SS despite the lack of ClpV. T4SS was found in 25% of complete C. concisus genomes. This study also found that GS2 strains had larger genomes and higher GC content than GS1 strains and more often had plasmids. In conclusion, this study provides fundamental genomic data for understanding C. concisus plasmids, genomospecies features, evolution, secretion systems and pathogenicity.

High risk of microscopic colitis after Campylobacter concisus infection: population-based cohort study

OBJECTIVE

Microscopic colitis (MC) encompasses the two histopathological distinct entities of collagenous colitis (CC) and lymphocytic colitis (LC). In this Danish population-based cohort study, we examined the risk of MC following stool culture with Campylobacter concisus, C. jejuni, non-typhoidal Salmonella or a culture-negative stool test.

DESIGN

We identified patients with a first-time positive stool culture with C. concisus, C. jejuni, non-typhoidal Salmonella or negative stool test, from 2009 through 2013 in North Denmark Region, Denmark, and matched each with 10 population comparisons. All subjects were followed up until 1 March 2018 using Systematised Nomenclature of Medicine codes from The Danish Pathology Register for incident diagnoses of CC and LC. We computed risk and adjusted HRs with 95% CIs for MC among patients and comparisons.

RESULTS

We identified 962 patients with C. concisus, 1725 with C. jejuni, 446 with Salmonella and 11 825 patients with culture-negative stools. The MC risk and HR versus comparisons were high for patients with C. concisus (risk 6.2%, HR 32.4 (95% CI 18.9 to 55.6)), less for C. jejuni (risk 0.6%, HR 3.7 (95% CI 1.8 to 7.7)), low for Salmonella (risk 0.4%, HR 2.2 (95% CI 0.5 to 10.8)) and for patients with negative stool testing (risk 3.3%, HR 19.6 (95% CI 16.4 to 23.4)). After exclusion of the first year of follow-up, the HRs were 9.3 (95% CI 4.1 to 20.1), 2.2 (95% CI 0.9 to 5.4), 1.3 (95% CI 0.2 to 11.1) and 5.6 (95% CI 4.6 to 7.2), respectively.

CONCLUSION

A high risk of MC was observed following C. concisus in stools. Further studies are needed to elucidate any underlying biological mechanisms.

Campylobacter concisus is prevalent in the gastrointestinal tract of patients with microscopic colitis

OBJECTIVES

Microscopic colitis (MC) is potentially induced by an inflammatory reaction to a luminal gut factor. The emerging pathogen Campylobacter concisus is associated with prolonged diarrhoea and subsequently increased risk of MC. We aimed to examine the prevalence of C. concisus in clinical samples from MC patients, analyse the subtypes collagenous colitis (CC) and lymphocytic colitis (LC), and characterise C. concisus isolates from MC patients by genomic sequencing.

METHODS

Mucosal biopsies were collected by sigmoidoscopy in 55 MC patients (CC n = 34, LC n = 21). Saliva and faecal samples were also collected. A two-step cultivation method and PCR established C. concisus prevalence. Biopsy and faecal isolates were sequenced for genomic analysis.

RESULTS

Cultivation revealed C. concisus in saliva 55/55, faeces 14/55 and biopsies 69/436, which was confirmed by PCR in faeces 28/55 and biopsies 215/430. Interestingly, biopsy prevalence was higher in CC patients than in LC patients both by cultivation (50/270 vs.19/166, p = .058) and by PCR (175/270 vs. 40/160, p < .0001). Long disease duration also affected biopsy prevalence both by cultivation 30/244 (<2 years) vs. 39/192 (>2 years) (p = .025) and by PCR 103/239 (<2 years) vs. 112/191 (>2 years) (p = .002). Genomic analysis on sixty biopsy and twenty faecal isolates revealed division into two clusters/genomospecies and a high presence of various, putative virulence genes (zot, exotoxin 9 and hcp).

CONCLUSIONS

Campylobacter concisus was prevalent in MC patients. Interestingly, the biopsy prevalence differed in biopsies from CC and LC patients and with regard to disease duration. Further studies are needed to elucidate this possible association.

An Unusual Case of Campylobacter jejuni Gastroenteritis Presenting with Acute Reversible Encephalopathy in an Immunocompetent Host

Campylobacter jejuni gastroenteritis is the most frequent organism associated with acute infectious diarrhea worldwide. The clinical presentation involves fever, diarrhea, rigors, and myalgias. Other extraintestinal symptoms that have been described involve delirium and other neurological complications, and the most well-known is Guillain-Barré, where there is cross-reactivity between the gastrointestinal tract and the brain. Despite previously described multiple neurological complications, there is a lack of clinical data on the association of Campylobacter-related gastroenteritis with acute encephalopathy in immunocompetent patients. The type of population, immunocompetent stage, and unfamiliarity with the clinical presentation makes this a challenging diagnosis for clinicians. We report a case of Campylobacter gastroenteritis associated with acute encephalopathy in an immunocompetent patient.

Antimicrobial Susceptibility of Campylobacter isolates in the Capital of North Macedonia

BACKGROUND

Campylobacter infections are typically self-limited, but in cases with severe enteritis, immuno-compromised system and bacteremia, an appropriate antimicrobial treatment is demanding. Our study aim was to determine the isolation rate of Campylobacter among patients with acute enteritis in the capital of North Macedonia and its antimicrobial susceptibility.

MATERIAL AND METHODS

A total number of 3820 patients clinically diagnosed as acute enteritis, were included in the study. Stool samples were collected and Campylobacter was isolated and identified by classical microbiological methods. Antimicrobial susceptibility of all isolates to Ceftriaxone, Amoxicillin-clavulonic acid, Erythromycin, Ciprofloxacin, Tetracycline and Gentamicin was determined by disc-diffusion technique. Additionally, minimal inhibitory concentrations of all Campylobacter isolates against erythromycin, ciprofloxacin and tetracycline were determined by Epsilon gradient tests.

RESULTS

Campylobacter species was isolated in 97 patients. Although the mean isolation rate of Campylobacter spp. during the whole study period was 2.53%, a statistically significant increase was detected in 2016 and 2017, in comparison with the data from previous four years of the study. The isolation rate of Campylobacter spp. didn't reveal statistically significant difference between males and females (p > 0.05). 46.4 % of patients with Campylobacter enteritis were children at the age under 15 years. Forty-three C. jejuni isolates were susceptible to all six antibiotics, but the remaining 44 isolates revealed resistance to at least one antibiotic. C. coli isolates were resistant to 3 antibiotics simultaneously. Two C. coli isolates only, were susceptible to all 6 antibiotics. 40.90% of C. jejuni and 50% of C. coli isolates were resistant to beta-lactams, fluoroquinolones and tetracyclines, simultaneously.

CONCLUSION

The increase of the isolation rate of Campylobacter from patients with acute enteritis indicates the need for permanent isolation and identification of Campylobacter from every clinically diagnosed patient, as acute enteritis. Erythromicin is the most effective antibiotic for treatment of Campylobacter enteritis in our patients. The high level of Campylobacter resistance to beta-lactams, fluoroquinolones and tetracyclines requires more rational approach in the treatment of Campylobacter enteritis.

Analyses of energy metabolism and stress defence provide insights into Campylobacter concisus growth and pathogenicity

Campylobacter concisus is an emerging enteric pathogen that is associated with inflammatory bowel disease. Previous studies demonstrated that C. concisus is non-saccharolytic and hydrogen gas (H2) is a critical factor for C. concisus growth. In order to understand the molecular basis of the non-saccharolytic and H2-dependent nature of C. concisus growth, in this study we examined the pathways involving energy metabolism and oxidative stress defence in C. concisus. Bioinformatic analysis of C. concisus genomes in comparison with the well-studied enteric pathogen Campylobacter jejuni was performed. This study found that C. concisus lacks a number of key enzymes in glycolysis, including glucokinase and phosphofructokinase, and the oxidative pentose phosphate pathway. C. concisus has an incomplete tricarboxylic acid cycle, with no identifiable succinyl-CoA synthase or fumarate hydratase. C. concisus was inferred to use fewer amino acids and have fewer candidate substrates as electron donors and acceptors compared to C. jejuni. The addition of DMSO or fumarate to media resulted in significantly increased growth of C. concisus in the presence of H2 as an electron donor, demonstrating that both can be used as electron acceptors. Catalase, an essential enzyme for oxidative stress defence in C. jejuni, and various nitrosative stress enzymes, were not found in the C. concisus genome. Overall, C. concisus is inferred to have a non-saccharolytic metabolism in which H2 is central to energy conservation, and a narrow selection of carboxylic acids and amino acids can be utilised as organic substrates. In conclusion, this study provides a molecular basis for the non-saccharolytic and hydrogen-dependent nature of C. concisus energy metabolism pathways, which provides insights into the growth requirements and pathogenicity of this species.

Prevalence of campylobacter enteritis in children under 5 years hospitalised for diarrhoea in two cities of Northeast India

Background

Campylobacter enteritis is the major cause of bacterial gastroenteritis worldwide. In recent years, there has been a rise in global incidence of campylobacteriosis. There are no available data on prevalence of Campylobacter diarrhoea from Northeast India.

Materials and Methods

The study investigated archival stool samples collected between 2014 and 2016 from two hospitals of Northeast India. A total of 407 archival stool samples from cases of diarrhoea under 5 years of age were screened for Campylobacter spp. using commercial probe-based real-time polymerase chain reaction assay.

Results

Campylobacter spp. was detected in overall 10.1% (41/407; 95% confidence interval: 7.4%-13.3%) in children under 5 years hospitalised for diarrhoea. The prevalence was significantly higher from Dibrugarh, Assam, compared to Dimapur, i.e., 13.4% (27/201) versus 6.8% (14/206), respectively (P = 0.02). Campylobacter detection was highest in the month of June and July compared to December and January (20%-18.8% vs. 8.9%-6.2%, respectively). Further, Campylobacter infection was higher in the age group below 24 months (11.7%) compared to above 24 months (7.0%). Campylobacter jejuni was detected in 80.5% of the positive cases.

Conclusion

The present study reveals that Campylobacter infection is endemic in the studied regions of Northeast India and microbiological laboratories of the region should actively pursue the isolation or detection of Campylobacter spp. in cases of diarrhoea in routine stool cultures.

A Gallus gallus Model for Determining Infectivity of Zoonotic Campylobacter

To better understand public health implications of waterfowl as reservoirs for zoonotic sources of Campylobacter in recreational waters, we developed a Gallus gallus (chick) model of infection to assess the pathogenicity of environmental isolates of Campylobacter. This method involved exposure of 1-day-old chicks through ingestion of water, the natural route of infection. Viable Campylobacter from laboratory-infected animals were monitored by using a modified non-invasive sampling of fresh chick excreta followed by a passive polycarbonate-filter migration culture assay. The method was used to evaluate the infectivities of three laboratory strains of Campylobacter spp. (Campylobacter coli, Campylobacter jejuni, and Campylobacter lari), three clinical isolates of C. jejuni, and four environmental Campylobacter spp. isolated from California gulls (Larus californicus). The results revealed that chicks were successfully infected with all laboratory and clinical isolates of Campylobacter spp. through ingestion of Campylobacter-spiked water, with infection rates ranging from <10 to >90% in a dose-dependent manner. More importantly, exposure of chicks with Campylobacter spp. isolated from Gallus gallus excreta also resulted in successful establishment of infection (≤90%). Each monitored Campylobacter spp. contained ≥7.5 × 10⁴ CFU⋅g^–1 of feces 7 days post-exposure. These results suggest that a G. gallus model can be used to assess infectivity of Campylobacter isolates, including gull and human clinical isolates. Use of an avian animal model can be applied to assess the importance of birds, such as the G. gallus, as potential contributors of waterborne-associated outbreaks of campylobacteriosis.

Human campylobacteriosis: A public health concern of global importance

Campylobacter species are among the leading cause of bacterial foodborne and waterborne infections. In addition, Campylobacter is one of the major causative agent of bacterial gastrointestinal infections and the rise in the incidence of Campylobacter infections have been reported worldwide. Also, the emergence of some Campylobacter species as one of the main causative agent of diarrhea and the propensity of these bacteria species to resist the actions of antimicrobial agents; position them as a serious threat to the public health. This paper reviews Campylobacter pathogenicity, infections, isolation and diagnosis, their reservoirs, transmission pathways, epidemiology of Campylobacter outbreaks, prevention and treatment option, antibiotics resistance and control of antibiotics use.

Pathogenomics of Emerging Campylobacter Species

Campylobacter is among the four main causes of gastroenteritis worldwide and has increased in both developed and developing countries over the last 10 years. The vast majority of reported Campylobacter infections are caused by Campylobacter jejuni and, to a lesser extent, C. coli; however, the increasing recognition of other emerging Campylobacter pathogens is urgently demanding a better understanding of how these underestimated species cause disease, transmit, and evolve. In parallel to the enhanced clinical awareness of campylobacteriosis due to improved diagnostic protocols, the application of high-throughput sequencing has increased the number of whole-genome sequences available to dozens of strains of many emerging campylobacters. This has allowed for comprehensive comparative pathogenomic analyses for several species, such as C. fetus and C. concisus These studies have started to reveal the evolutionary forces shaping their genomes and have brought to light many genomic features related to pathogenicity in these neglected species, promoting the development of new tools and approaches relevant for clinical microbiology. Despite the need for additional characterization of genomic diversity in emerging campylobacters, the increasing body of literature describing pathogenomic studies on these species deserves to be discussed from an integrative perspective. This review compiles the current knowledge and highlights future work toward deepening our understanding about genome dynamics and the mechanisms governing the evolution of pathogenicity in emerging Campylobacter species, which is urgently needed to develop strategies to prevent or control the spread of these pathogens.

[Oral microbiota and inflammatory bowel disease]

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract with a high incidence but a poor therapeutic outcome. However, IBD is generally caused by complicated interactions between environmental factors and gut microflora in genetically susceptible individuals. In view of a series of oral manifestations in patients with IBD and a high detection rate of oral bacteria among this population, oral microbiota may play an important role in the development of IBD. This article reviews the relationship between oral microbiota and IBD.

Detection and molecular typing of campylobacter isolates from human and animal faeces in coastal belt of Odisha, India

Introduction

Campylobacter-mediated diarrhoea is one of the major causes of gastroenteritis globally. A majority of the Campylobacter spp. that cause disease in humans have been isolated from animals. Faecal contamination of food and water is the identified frequent cause of human campylobacteriosis.

Methodology

In the present study, faecal samples from patients with symptoms of acute diarrhoea (n = 310) and domestic animals including cows (n = 60), sheep (n = 45) and goats (n = 45) were collected from the same localities in the peri-urban Bhubaneswar city. Genomic DNA isolation followed by polymerase chain reaction and sequencing was employed to analyse Campylobacter spp.-positive samples.

Results

Of the 460 faecal samples, 16.77% of human samples and 25.33% of animal samples were found to be positive for Campylobacter spp. Among animals, the isolation rate was highest in sheep followed by cows and goats with 9.33%, 8.66% and 7.33%, respectively. The highest number of Campylobacter-positive cases was diagnosed in infants of 2-5 years age. Concurrent infection of other pathogens in addition to Campylobacter spp. was frequently detected in the samples.

Conclusion

The present study showed the incidence of Campylobacter infections in human and different animal species in and around Bhubaneswar, Odisha. The analysis suggested that domestic animals can be the potential sources for human campylobacteriosis in the region.

Epidemiology of Campylobacter Gastroenteritis in New Zealand Children and the Effect of The Campylobacter Strategy: A 20-year Observational Study

BACKGROUND

Campylobacter species are a common cause of gastroenteritis in New Zealand (NZ) as well as worldwide. This study aimed to describe epidemiologic trends in disease notifications and hospital admissions because of Campylobacter gastroenteritis in NZ children from 1997 to 2016.

METHODS

In this population-based descriptive study, age-specific and age-standardized notification and hospitalization rates were analyzed for Campylobacter infections in children <15 years of age. Variations in disease by time, sex, age, ethnicity and geography were described.

RESULTS

During the 20-year period considered, there were 39,970 notifications (59.1% male) and 1458 hospitalizations (61.8% male) because of Campylobacter gastroenteritis in NZ children. Before 2006, notification rates increased by 3.4% annually [95% confidence interval (CI): 0.7%-6.2%], with a peak of 340 notifications per 100,000 children in 2003. The average percentage change (APC) in hospitalizations was 7.4% (95% CI: 4.0%-10.9%) in the same period. From 2006 to 2008, notification and hospitalization rates fell by 25% and 30%, respectively. Since 2008, age-standardized incidence rates have been stable at 161 notifications (APC: -3.1; 95% CI: 0.82 to -6.9) and 6.73 hospitalizations (APC: 2.2; 95% CI: -2.0 to 6.5) per 100,000 children per year. Notification rates were highest in children 1-4 years of age. Hospitalizations rates were highest in children <1 year of age.

CONCLUSIONS

NZ has previously had high rates of Campylobacter gastroenteritis in children. Implementation of a national strategy to reduce foodborne Campylobacter infection appears to have contributed to an observed reduction in rates between 2006 and 2008. The burden of Campylobacter disease is highest in the community health setting, with only a small proportion of cases needing hospitalization.

Risk of inflammatory bowel disease after Campylobacter jejuni and Campylobacter concisus infection: a population-based cohort study

Objectives: In this population-based cohort study, we aimed to examine the risk of IBD following a positive stool culture with Campylobacter jejuni or Campylobacter concisus, as well as following culture-negative stool testing. Materials and methods: Patients with a first-time positive stool culture with C. jejuni or C. concisus, as well as negative stool testing, from 2009 through 2013 in North Denmark Region, Denmark, were identified. Patients diagnosed with IBD during follow-up (to 1 March 2018) were identified using national registries. For each case, we selected ten population comparisons matched by age, gender, and calendar-time. Results: We identified 1693 patients with C. jejuni, 910 C. concisus-positive patients, and 11,383 patients with culture-negative stools. During the first year of follow-up C. jejuni-positive patients had higher risk of IBD (HR 2.2, 95% CI 1.3-3.7) compared to population comparisons, but not after exclusion of the first year (HR 1.1, 95% CI 0.5-2.3). Campylobacter concisus-positive patients and culture-negative patients had similar risk of IBD (HR 12.9, 95% CI 7.2-22.9 and HR 8.7, 95% CI 7.5-10.2), during the first year, which decreased to (HR 3.3, 95% CI 1.3-8.5 and HR 3.2, 95% CI 2.6-4.0) after exclusion of the first year. Conclusions: This study does not support exposure of C. jejuni or C. concisus infection as a causal trigger in subsequent development of IBD, since culture-negative patients had similar risk for IBD on long term follow-up. Additional studies including C. concisus exposures for an evaluation of the specific risk of IBD are needed.

Experience of &lt;italic&gt;Campylobacter&lt;/italic&gt; gastroenteritis in Korean children: Single-center study

Although Campylobacter is the main cause for bacterial acute gastroenteritis (AGE), there has been no notable clinical research into it, especially for Korean children. In this study, we share our experience of clinical, laboratory and image findings with Campylobacter AGE. Methods Between May 2013 and June 2016, children diagnosed as having Campylobacter AGE were retrospectively enrolled in our study. Campylobacter AGE was considered diagnosed when a patient had symptoms of bacterial AGE and a positive Campylobacter result in stool using multiplex PCR. Results Among 539 patients with suspected bacterial AGE, 31 (5.8%) patients had a positive result for Campylobacter. The average age of the 31 patients was 10.2 ± 5.0 years with a range between 1.1 and 16.9 years. Eighteen (58%) of the total patients were hospitalized between June and August. Diarrhea (93.5%), abdominal pain (83%) and fever (83%) were common symptoms. For 20 patients (65%), diarrhea lasted for less than three days, and fever lasted for 2.1 days on average. Among the 20 patients subjected to imaging studies, 12 patients (60%) showed bowel wall thickening on the right side of colon. In blood tests of 30 patients, 22 (73%) and 29 (97%) patients exhibited leukocytosis and elevated C-reactive protein, respectively. During treatment for Campylobacter AGE, prediagnostic empirical antibiotics were used for 6 (19%) patients. All patients recovered without complications. Conclusions Among the children with suspected bacterial AGE, 5.8% had a positive result on Campylobacter in stool using multiplex PCR. Therefore, we observe that Campylobacter AGE should be considered in school-age children who have diarrhea, fever, and abdominal pain.

Motility and biofilm formation of the emerging gastrointestinal pathogen Campylobacter concisus differs under microaerophilic and anaerobic environments

Campylobacter concisus has been isolated from patients with gastroenteritis and inflammatory bowel disease (IBD), as well as healthy subjects. While strain differences may plausibly explain virulence differentials, an alternative hypothesis posits that the pathogenic potential of this species may depend on altered ecosystem conditions in the inflamed gut. One potential difference is oxygen availability, which is frequently increased under conditions of inflammation and is known to regulate bacterial virulence. Hence, we hypothesized that oxygen influences C. concisus physiology. We therefore characterized the effect of microaerophilic or anaerobic environments on C. concisus motility and biofilm formation, two important determinants of host colonization and dissemination. C. concisus isolates (n = 46) sourced from saliva, gut mucosal biopsies and feces of patients with IBD (n = 23), gastroenteritis (n = 8) and healthy subjects (n = 13), were used for this study. Capacity to form biofilms was determined using crystal violet assay, while assessment of dispersion through soft agar permitted motility to be assessed. No association existed between GI disease and either motility or biofilm forming capacity. Oral isolates exhibited significantly greater capacity for biofilm formation compared to fecal isolates (p<0.03), and showed a strong negative correlation between motility and biofilm formation (r = -0.7; p = 0.01). Motility significantly increased when strains were cultured under microaerophilic compared to anaerobic conditions (p<0.001). Increased biofilm formation under microaerophillic conditions was also observed for a subset of isolates. Hence, differences in oxygen availability appear to influence key physiological aspects of the opportunistic gastrointestinal pathogen C. concisus.

Novel Campylobacter concisus lipooligosaccharide is a determinant of inflammatory potential and virulence

The pathogenicity of Campylobacter concisus, increasingly found in the human gastrointestinal (GI) tract, is unclear. Some studies indicate that its role in GI conditions has been underestimated, whereas others suggest that the organism has a commensal-like phenotype. For the enteropathogen C. jejuni, the lipooligosaccharide (LOS) is a main driver of virulence. We investigated the LOS structure of four C. concisus clinical isolates and correlated the inflammatory potential of each isolate with bacterial virulence. Mass spectrometric analyses of lipid A revealed a novel hexa-acylated diglucosamine moiety with two or three phosphoryl substituents. Molecular and fragment ion analysis indicated that the oligosaccharide portion of the LOS had only a single phosphate and lacked phosphoethanolamine and sialic acid substitution, which are hallmarks of the C. jejuni LOS. Consistent with our structural findings, C. concisus LOS and live bacteria induced less TNF-α secretion in human monocytes than did C. jejuni Furthermore, the C. concisus bacteria were less virulent than C. jejuni in a Galleria mellonella infection model. The correlation of the novel lipid A structure, decreased phosphorylation, and lack of sialylation along with reduced inflammatory potential and virulence support the significance of the LOS as a determinant in the relative pathogenicity of C. concisus.

The Clinical Importance of Campylobacter concisus and Other Human Hosted Campylobacter Species

Historically, Campylobacteriosis has been considered to be zoonotic; the Campylobacter species that cause human acute intestinal disease such as Campylobacter jejuni and Campylobacter coli originate from animals. Over the past decade, studies on human hosted Campylobacter species strongly suggest that Campylobacter concisus plays a role in the development of inflammatory bowel disease (IBD). C. concisus primarily colonizes the human oral cavity and some strains can be translocated to the intestinal tract. Genome analysis of C. concisus strains isolated from saliva samples has identified a bacterial marker that is associated with active Crohn's disease (one major form of IBD). In addition to C. concisus, humans are also colonized by a number of other Campylobacter species, most of which are in the oral cavity. Here we review the most recent advancements on C. concisus and other human hosted Campylobacter species including their clinical relevance, transmission, virulence factors, disease associated genes, interactions with the human immune system and pathogenic mechanisms.

Comparative genomics of Campylobacter concisus: Analysis of clinical strains reveals genome diversity and pathogenic potential

In recent years, an increasing number of Campylobacter species have been associated with human gastrointestinal (GI) diseases including gastroenteritis, inflammatory bowel disease, and colorectal cancer. Campylobacter concisus, an oral commensal historically linked to gingivitis and periodontitis, has been increasingly detected in the lower GI tract. In the present study, we generated robust genome sequence data from C. concisus strains and undertook a comprehensive pangenome assessment to identify C. concisus virulence properties and to explain potential adaptations acquired while residing in specific ecological niche(s) of the GI tract. Genomes of 53 new C. concisus strains were sequenced, assembled, and annotated including 36 strains from gastroenteritis patients, 13 strains from Crohn’s disease patients and four strains from colitis patients (three collagenous colitis and one lymphocytic colitis). When compared with previous published sequences, strains clustered into two main groups/genomospecies (GS) with phylogenetic clustering explained neither by disease phenotype nor sample location. Paired oral/faecal isolates, from the same patient, indicated that there are few genetic differences between oral and gut isolates which suggests that gut isolates most likely reflect oral strain relocation. Type IV and VI secretion systems genes, genes known to be important for pathogenicity in the Campylobacter genus, were present in the genomes assemblies, with 82% containing Type VI secretion system genes. Our findings indicate that C. concisus strains are genetically diverse, and the variability in bacterial secretion system content may play an important role in their virulence potential.

Immune response-eliciting exposure to Campylobacter vastly exceeds the incidence of clinically overt campylobacteriosis but is associated with similar risk factors: A nationwide serosurvey in the Netherlands

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.

Genomic analysis of oral Campylobacter concisus strains identified a potential bacterial molecular marker associated with active Crohn's disease

Campylobacter concisus is an oral bacterium that is associated with inflammatory bowel disease (IBD) including Crohn’s disease (CD) and ulcerative colitis (UC). C. concisus consists of two genomospecies (GS) and diverse strains. This study aimed to identify molecular markers to differentiate commensal and IBD-associated C. concisus strains. The genomes of 63 oral C. concisus strains isolated from patients with IBD and healthy controls were examined, of which 38 genomes were sequenced in this study. We identified a novel secreted enterotoxin B homologue, Csep1. The csep1 gene was found in 56% of GS2 C. concisus strains, presented in the plasmid pICON or the chromosome. A six-nucleotide insertion at the position 654–659 bp in csep1 (csep1-6bpi) was found. The presence of csep1-6bpi in oral C. concisus strains isolated from patients with active CD (47%, 7/15) was significantly higher than that in strains from healthy controls (0/29, P = 0.0002), and the prevalence of csep1-6bpi positive C. concisus strains was significantly higher in patients with active CD (67%, 4/6) as compared to healthy controls (0/23, P = 0.0006). Proteomics analysis detected the Csep1 protein. A csep1 gene hot spot in the chromosome of different C. concisus strains was found. The pICON plasmid was only found in GS2 strains isolated from the two relapsed CD patients with small bowel complications. This study reports a C. concisus molecular marker (csep1-6bpi) that is associated with active CD.

Molecular epidemiology and comparative genomics of Campylobacter concisus strains from saliva, faeces and gut mucosal biopsies in inflammatory bowel disease

Campylobacter concisus is an emerging pathogen associated with inflammatory bowel disease (IBD), yet little is known about the genetic diversity of C. concisus in relation to host niches and disease. We isolated 104 C. concisus isolates from saliva, mucosal biopsies and faecal samples from 41 individuals (26 IBD, 3 Gastroenteritis (GE), 12 Healthy controls (HC)). Whole genomes were sequenced and the dataset pan-genome examined, and genomic information was used for typing using multi-locus-sequence typing (MLST). C. concisus isolates clustered into two main groups/genomospecies (GS) with 71 distinct sequence types (STs) represented. Sampling site (p < 0.001), rather than disease phenotype (p = 1.00) was associated with particular GS. We identified 97 candidate genes associated with increase or decrease in prevalence during the anatomical descent from the oral cavity to mucosal biopsies to faeces. Genes related to cell wall/membrane biogenesis were more common in oral isolates, whereas genes involved in cell transport, metabolism and secretory pathways were more prevalent in enteric isolates. Furthermore, there was no correlation between individual genetic diversity and clinical phenotype. This study confirms the genetic heterogeneity of C. concisus and provides evidence that genomic variation is related to the source of isolation, but not clinical phenotype.

Incidence of Campylobacter concisus and C. ureolyticus in traveler's diarrhea cases and asymptomatic controls in Nepal and Thailand

Background

Campylobacter concisus and C. ureolyticus have emerged in recent years as being associated with acute and prolonged gastroenteritis and implicated in the development of inflammatory bowel diseases. However, there are limited data on the prevalence of these microorganisms in Southeast Asia. In this study, 214 pathogen-negative stool samples after laboratory examination for common enteric pathogens to include C. jejuni and C. coli by culture from two case–control traveler’s diarrhea (TD) studies conducted in Thailand (cases = 26; controls = 30) and Nepal (cases = 83; controls = 75) respectively were assayed by PCR for the detection of Campylobacter 16S rRNA and two specific heat shock protein genes specific for C. concisus (cpn60) and C. ureolyticus (Hsp60) respectively.

Results

Campylobacter 16S rRNA was detected in 28.5% (61/214) of the pathogen-negative TD stool samples (CIWEC Travel Medicine Clinic, Kathmandu, Nepal: cases = 36, control = 14; Bamrungrad International Hospital, Bangkok, Thailand: cases = 9, controls = 2). C. consisus was identified significantly more often in TD cases in Nepal (28.9%; 24/83) as compared to controls (4%; 3/75) (OR = 9.76; 95% CI 2.80–34.02; P = 0.0003) while C. consisus was detected in only two cases (2/26; 7.7%) and none of the controls stool samples from Thailand. C. ureolyticus was detected in four cases (4.8%; 4/83) and four controls (5.3%; 4/75) and in one case (3.8%; 1/26) and one control (3.1%; 1/30) from Nepal and Thailand respectively. C. jejuni and C. coli were isolated in 18.3 and 3.4% of the cases and in 4.0 and 1.4% of the controls in stool samples from both Thailand and Nepal respectively while C. concisus nor C. ureolyticus were not tested for in these samples.

Conclusion

These findings suggest that C. concisus potentially is a pathogen associated with TD in Nepal. To our knowledge, this is the first report of C. concisus and C. ureolyticus detected from traveler’s diarrhea cases from travelers to Nepal and Thailand.

Campylobacter concisus Genomospecies 2 Is Better Adapted to the Human Gastrointestinal Tract as Compared with Campylobacter concisus Genomospecies 1

Campylobacter concisus was previously shown to be associated with inflammatory bowel disease including Crohn's disease (CD) and ulcerative colitis (UC). C. concisus has two genomospecies (GS). This study systematically examined the colonization of GS1 and GS2 C. concisus in the human gastrointestinal tract. GS1 and GS2 specific polymorphisms in 23S rRNA gene were identified by comparison of the 23S rRNA genes of 49 C. concisus strains. Two newly designed PCR methods, based on the polymorphisms of 23S rRNA gene, were developed and validated. These PCR methods were used to detect and quantify GS1 and GS2 C. concisus in 56 oral and enteric samples collected from the gastrointestinal tract of patients with IBD and healthy controls. Meta-analysis of the composition of the isolated GS1 and GS2 C. concisus strains in previous studies was also conducted. The quantitative PCR methods revealed that there was more GS2 than GS1 C. concisus in samples collected from the upper and lower gastrointestinal tract of both patients with IBD and healthy controls, showing that GS2 C. concisus is better adapted to the human gastrointestinal tract. Analysis of GS1 and GS2 composition of isolated C. concisus strains in previous studies showed similar findings except that in healthy individuals a significantly lower GS2 than GS1 C. concisus strains were isolated from fecal samples, suggesting a potential difference in the C. concisus strains or the enteric environment between patients with gastrointestinal diseases and healthy controls. This study provides novel information regarding the adaptation of different genomospecies of C. concisus in the human gastrointestinal tract.

Epidemiology of campylobacteriosis in Denmark 2000-2015

Campylobacter is the most frequently occurring cause of bacterial gastroenteritis in Europe. Unlike other zoonotic diseases, European-wide incidences of Campylobacter infections have increased during the past decade, resulting in a significant disease burden. In Denmark, campylobacteriosis is notifiable by laboratory and a unique registration system of electronic transfer and storage of notified Campylobacter cases linked to the national person register of age, gender and geographical location allows collection of comprehensive case data. Using national surveillance data, we describe Campylobacter infections in Denmark from 2000 to 2015, focusing on age-specific incidences, geography, seasonality and outbreaks. During the observed period, a total of 60,725 Campylobacter infections were registered with a mean annual incidence of 69.3 cases/100,000 population. From 2000 to 2014, the incidence of campylobacteriosis decreased by 20%, followed by an apparent increase of 20% from 2014 to 2015. Approximately one-third of cases were travel-related. Incidences were highest in males, young adults aged 20-29 years and children under 5 years of age. Generally, children under 10 years of age living in rural areas were at higher risk of infection. Infection patterns were seasonal with an increase from May to October, peaking in August. Outbreaks were identified each year, including four large waterborne outbreaks which all occurred following heavy rainfall events. For the most part, patterns of Campylobacter infection in Denmark during 2000 to 2015 remained remarkably constant and followed what is known about the disease with respect to demographic, temporal and spatial characteristics. To establish better targeted prevention and control measures, the current knowledge gaps regarding both Campylobacter microbiology (degree of clonal diversity and clustering) and the importance of different risk factors (food versus environment/climate) need to be filled.

Azathioprine, Mercaptopurine, and 5-Aminosalicylic Acid Affect the Growth of IBD-Associated Campylobacter Species and Other Enteric Microbes

Campylobacter concisus is a bacterium that is associated with inflammatory bowel disease (IBD). Immunosuppressive drugs including azathioprine (AZA) and mercaptopurine (MP), and anti-inflammatory drug such as 5-aminosalicylic acid (5-ASA) are commonly used to treat patients with IBD. This study aimed to examine the effects of AZA, MP, and 5-ASA on the growth of IBD-associated bacterial species and to identify bacterial enzymes involved in immunosuppressive drug metabolism. A total of 15 bacterial strains of five species including 11 C. concisus strains, Bacteroides fragilis, Bacteroides vulgatus, Enterococcus faecalis, and Escherichia coli were examined. The impact of AZA, MP, and 5-ASA on the growth of these bacterial species was examined quantitatively using a plate counting method. The presence of enzymes involved in AZA and MP metabolism in these bacterial species was identified using bioinformatics tools. AZA and MP significantly inhibited the growth of all 11 C. concisus strains. C. concisus strains were more sensitive to AZA than MP. 5-ASA showed inhibitory effects to some C. concisus strains, while it promoted the growth of other C. concisus strains. AZA and MP also significantly inhibited the growth of B. fragilis and B. vulgatus. The growth of E. coli was significantly inhibited by 200 μg/ml of AZA as well as 100 and 200 μg/ml of 5-ASA. Bacterial enzymes related to AZA and MP metabolism were found, which varied in different bacterial species. In conclusion, AZA and MP have inhibitory effects to IBD-associated C. concisus and other enteric microbes, suggesting an additional therapeutic mechanism of these drugs in the treatment of IBD. The strain dependent differential impact of 5-ASA on the growth of C. concisus may also have clinical implication given that in some cases 5-ASA medications were found to cause exacerbations of colitis.

Motility of Campylobacter concisus isolated from saliva, feces, and gut mucosal biopsies

Campylobacter concisus is an emerging pathogen associated with gastrointestinal disorders such as gastroenteritis and inflammatory bowel diseases (IBD), but the species is also found in healthy subjects. The heterogeneous genome of C. concisus increases the likelihood of varying virulence between strains. Flagella motility is a crucial virulence factor for the well-recognized Campylobacter jejuni; therefore, this study aimed to analyze the motility of C. concisus isolated from saliva, gut biopsies, and feces of patients with IBD, gastroenteritis, and healthy subjects. The motility zones of 63 isolates from 52 patients were measured after microaerobic growth in soft-agar plates for 72 hours. The motility of C. concisus was significantly lower than that of Campylobacter jejuni and Campylobacter fetus subsp. fetus. The motility of C. concisus varied between isolates (4-22 mm), but there was no statistical significant difference between isolates from IBD patients and healthy subjects (p = 0.14). A tendency of a larger motility zones was observed for IBD gut mucosa isolates, although it did not reach statistical significance (p = 0.13), and no difference was found between oral or fecal isolates between groups. In conclusion, the varying motility of C. concisus could not be related to disease outcome or colonization sites.

Azithromycin vs. Placebo for the Clinical Outcome in Campylobacter concisus Diarrhoea in Adults: A Randomized, Double-Blinded, Placebo-Controlled Clinical Trial

Campylobacter concisus has been associated with prolonged mild diarrhoea, but investigations regarding the efficacy of antimicrobial treatment have not been reported previously. We initiated a phase 3, single-centre, randomized, double-blinded, placebo-controlled study comparing the efficacy of 500 mg once-daily dose of azithromycin with a 500 mg once-daily dose of placebo for three days, for the treatment of C. concisus diarrhoea in adult patients with a follow-up period of ten days. If symptoms persisted at day ten, the patient was offered cross-over study treatment of three days and another ten-day follow-up period. The primary efficacy endpoint was the clinical response, defined as time to cessation of diarrhoea (<3 stools/day or reversal of accompanying symptoms). Our estimated sample size was 100 patients. We investigated a total of 10,036 diarrheic stool samples from 7,089 adult patients. Five-hundred and eighty-eight C. concisus positive patients were assessed for eligibility, of which 559 were excluded prior to randomization. The three main reasons for exclusion were duration of diarrhoea longer than 21 days (n = 124), previous antibiotic treatment (n = 113), and co-pathogens in stools (n = 87). Therefore, 24 patients completed the trial with either azithromycin (n = 12) or placebo (n = 12). Both groups presented symptoms of mild, prolonged diarrhoea with a mean duration of 18 days (95% CI: 16-19). One person in the azithromycin group and four from the placebo group chose to continue with crossover medication after the initial ten-day period. In the azithromycin group, there was a mean of seven days (95% CI: 5-9) to clinical cure and for the placebo group it was ten days (95% CI: 6-14) (OR-3 (95% CI: -7-1). We observed no differences in all examined outcomes between azithromycin treatment and placebo. However, due to unforeseen recruitment difficulties we did not reach our estimated sample size of 100 patients and statistical power to conclude on an effect of azithromycin treatment was not obtained.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT01531218.

Campylobacter concisus pathotypes induce distinct global responses in intestinal epithelial cells

The epithelial response to the opportunistic pathogen Campylobacter concisus is poorly characterised. Here, we assessed the intestinal epithelial responses to two C. concisus strains with different virulence characteristics in Caco-2 cells using RNAseq, and validated a subset of the response using qPCR arrays. C. concisus strains induced distinct response patterns from intestinal epithelial cells, with the toxigenic strain inducing a significantly more amplified response. A range of cellular functions were significantly regulated in a strain-specific manner, including epithelial-to-mesenchymal transition (NOTCH and Hedgehog), cytoskeletal remodeling, tight junctions, inflammatory responses and autophagy. Pattern recognition receptors were regulated, including TLR3 and IFI16, suggesting that nucleic acid sensing was important for epithelial recognition of C. concisus. C. concisus zonula occludens toxin (ZOT) was expressed and purified, and the epithelial response to the toxin was analysed using RNAseq. ZOT upregulated PAR2 expression, as well as processes related to tight junctions and cytoskeletal remodeling. C. concisus ZOT also induced upregulation of TLR3, pro-inflammatory cytokines IL6, IL8 and chemokine CXCL16, as well as the executioner caspase CASP7. Here, we characterise distinct global epithelial responses to C. concisus strains, and the virulence factor ZOT, and provide novel information on mechanisms by which this bacterium may affect the host.

Zonula occludens toxins and their prophages in Campylobacter species

BACKGROUND

We previously showed that zonula occludens toxin (Zot) encoded by Campylobacter concisus zot (808T) gene has the potential to initiate inflammatory bowel disease. This Zot protein caused prolonged intestinal epithelial barrier damage, induced intestinal epithelial and macrophage production of tumor necrosis factor-α and enhanced the responses of macrophages to other microbes. In order to understand the potential virulence of Zot proteins in other Campylobacter species, in this study we examined their presence, similarities, motifs and prophages.

METHODS

The presence of Zot proteins in Campylobacter species was examined by searching for the Zot family domain in multiple protein databases. Walker A and Walker B motifs in Zot proteins were identified using protein sequence alignment. A phylogenetic tree based on Campylobacter zot genes was constructed using maximum-likelihood method. Campylobacter Zot proteins were compared using protein sequence alignment. The zot-containing prophages in Campylobacter species were identified and compared with known prophage proteins and other viral proteins using protein sequence alignment and protein BLAST.

RESULTS

Twelve Zot proteins were found in nine Campylobacter species/subspecies. Among these Campylobacter species, three species had two Zot proteins and the remaining six species/subspecies had one Zot protein. Walker A and Walker B motifs and a transmembrane domain were found in all identified Campylobacter Zot proteins. The twelve Campylobacter zot genes from the nine Campylobacter species/subspecies formed two clusters. The ZotCampyType_1 proteins encoded by Cluster 1 Campylobacter zot genes showed high similarities to each other. However, ZotCampyType_2 proteins encoded by Cluster 2 Campylobacter zot genes were more diverse. Furthermore, the zot-containing Campylobacter prophages were identified.

CONCLUSION

This study reports the identification of two types of Campylobacter Zot proteins. The high similarities of ZotCampyType_1 proteins suggest that they are likely to have similar virulence. ZotCampyType_2 proteins are less similar to each other and their virulent properties, if any, remain to be examined individually.

Clinical relevance of infections with zoonotic and human oral species of Campylobacter

Genus Campylobacter has been recognized as a causative bacterial agent of animal and human diseases. Human Campylobacter infections have caused more concern. Campylobacters can be classified into two groups in terms of their original host: zoonotic and human oral species. The major zoonotic species are Campylobacter jejuni and Campylobacter coli, which mostly reside in the intestines of avian species and are transmitted to humans via consumption of contaminated poultry products, thus causing human gastroenteritis and other diseases as sequelae. The other campylobacters, human oral species, include C. concisus, C. showae, C. gracilis, C. ureolyticus, C. curvus, and C. rectus. These species are isolated from the oral cavity, natural colonization site, but have potential clinical relevance in the periodontal region to varying extent. Two species, C. jejuni and C. coli, are believed to be mainly associated with intestinal diseases, but recent studies suggested that oral Campylobacter species also play a significant role in intestinal diseases. This review offers an outline of the two Campylobacter groups (zoonotic and human oral), their virulence traits, and the associated illnesses including gastroenteritis.

Campylobacter concisus utilizes blood but not short chain fatty acids despite showing associations with Firmicutes taxa

Campylobacter concisus is a member of the oral microbiota that has been associated with the development of inflammatory bowel diseases. However, the role of the bacterium in disease aetiology remains poorly understood. Here, we examine optimal conditions for the growth of C. concisus, and the pathogenic potential of this bacterium in human gastrointestinal cells from the upper tract. Further, the presence of C. concisus in the lower tract of Crohn's disease (CD) patients undergoing therapy is observed, and the associations of C. concisus with the abundance of other microbial taxa and compounds they produce are evaluated. C. concisus strains had the ability to tolerate moderate levels of acidity, adhere to and invade esophageal and gastric cells; however, these properties did not correlate with their pathogenic potential in intestinal cells. The presence of the bacterium in the lower gut of CD patients was associated with an increased relative abundance of Faecalibacterium and Lachnospiraceae incertae sedis. Short chain fatty acids that can be produced by these microbial species did not appear to be responsible for this association. However, we identified genetic similarity between C. concisus and Firmicutes, specifically within aspartate and glutamate racemases. The potential pathogenesis of C. concisus in the upper gastrointestinal tract, and the responsiveness of the bacterium to therapy in a subset of CD patients warrant further investigation into whether this bacterium has a causal role in disease or its presence is incidental.

Optimized cultivation of Campylobacter concisus from gut mucosal biopsies in inflammatory bowel disease

Background

Campylobacter concisus is a commensal of the human oral flora that has been linked to prolonged diarrhea and inflammatory bowel disease (IBD). It has been detected more often from intestinal biopsies in patients with IBD compared to healthy controls using PCR-based techniques, whereas the number of C. concisus culture-positive biopsies in previous studies has been very limited. Determining the rate of viable isolates present in the gut mucosa is of great importance when evaluating the role in different disease presentations. We therefore investigated a novel two-step cultivation procedure combining anaerobic and microaerobic incubation from several gut mucosal sites to improve isolate yield, and compared this to PCR results, from IBD patients and healthy controls.

Results

Cultivation with the novel two-step procedure yielded a higher rate of C. concisus isolates from mucosal biopsies than previously reported by other methods. From 52 IBD patients, 52/245 (21 %) biopsies were culture positive for C. concisus, while 121/245 (49 %) of biopsies were PCR positive. For 26 healthy controls, the numbers were 23/182 (13 %) and 66/182 (36 %), respectively (p < 0.001). The rate of cultivation and PCR detection was higher for IBD patients compared to healthy controls (p = 0.021, p = 0.008, respectively).

Conclusions

Patients with IBD had a higher prevalence of C. concisus than healthy controls, by both cultivation and PCR detection. We found a higher rate of C. concisus isolates from gut mucosal biopsies in both IBD patients and healthy controls than in preceding studies, indicating that colonization of C. concisus in the gastrointestinal tract is more extensive than previously assumed.

Examination of the effects of Campylobacter concisus zonula occludens toxin on intestinal epithelial cells and macrophages

Background

Campylobacter concisus is a Gram-negative bacterium that is associated with inflammatory bowel disease (IBD). Some C. concisus strains carry zonula occludens toxin (zot) gene which has polymorphisms. This study investigated the effects of C. concisus Zot on intestinal epithelial cells and macrophages using cell line models.

Methods

Campylobacter concisuszot^808T gene, a polymorphism that is associated with active IBD, was cloned and expressed in Escherichia coli. The effects of C. concisus Zot on intestinal epithelial barrier were examined using Caco-2 cell model. Apoptosis induced by C. concisus Zot in Caco-2 cells was assessed by measuring the levels of caspase 3/7. The production of pro-inflammatory cytokines induced by C. concisus Zot in HT-29 cells and in THP-1 macrophage-like cells was measured using ELISA kits. Whether exposure to C. concisus Zot can affect the responses of macrophages to E. coli K12 was also investigated.

Results

Campylobacter concisus Zot caused prolonged intestinal epithelial barrier damage, induced intestinal epithelial cell apoptosis, induced epithelial production of TNF-α and IL-8 and upregulated TNF-α in THP-1 macrophage-like cells. Pre-exposure to C. concisus Zot significantly enhanced the production of TNF-α and IL-8 as well as phagocytosis by THP-1 macrophage-like cells in response to E. coli K12.

Conclusion

This study suggests that C. concisus Zot may have enteric pathogenic potential by damaging intestinal epithelial barrier, inducing intestinal epithelial and macrophage production of proinflammatory cytokines in particular TNF-α and enhancing the responses of macrophages to other enteric bacterial species.

Electronic supplementary material

The online version of this article (doi:10.1186/s13099-016-0101-9) contains supplementary material, which is available to authorized users.

Campylobacter concisus pathotypes are present at significant levels in patients with gastroenteritis

Given that Campylobacter jejuni is recognized as the most common cause of bacterial gastroenteritis worldwide, recent findings showing comparable levels of Campylobacter concisus in patients with gastroenteritis would suggest that this bacterium is clinically important. The prevalence and abundance of Campylobacter concisus in stool samples collected from patients with acute gastroenteritis was examined using quantitative real-time PCR. The associated virulence determinants exotoxin 9 and zonula occludens toxin DNA were detected for Campylobacter concisus-infected samples using real-time PCR. Campylobacter concisus was detected at high prevalence in patients with gastroenteritis (49.7 %), higher than that observed for Campylobacter jejuni (∼5 %). The levels of Campylobacter concisus were putatively classified into clinically relevant and potentially transient subgroups based on a threshold developed using Campylobacter jejuni levels, as the highly sensitive real-time PCR probably detected transient passage of the bacterium from the oral cavity. A total of 18 % of patients were found to have clinically relevant levels of Campylobacter concisus, a significant number of which also had high levels of one of the virulence determinants. Of these patients, 78 % were found to have no other gastrointestinal pathogen identified in the stool, which strongly suggests a role for Campylobacter concisus in the aetiology of gastroenteritis in these patients. These results emphasize the need for diagnostic laboratories to employ identification protocols for emerging Campylobacter species. Clinical follow-up in patients presenting with high levels of Campylobacter concisus in the intestinal tract is needed, given that it has been associated with more chronic sequelae.

Oral Campylobacter species: Initiators of a subgroup of inflammatory bowel disease?

In recent years, a number of studies detected a significantly higher prevalence of Campylobacter species such as Campylobacter concisus (C. concisus) in intestinal biopsies and fecal samples collected from patients with inflammatory bowel disease (IBD) compared to controls. Most of these Campylobacter species are not of zoonotic origin but are human oral Campylobacter species. Bacterial species usually cause diseases in the location where they colonize. However, C. concisus and other oral Campylobacter species are associated with IBD occurring at the lower parts of the gastrointestinal tract, suggesting that these Campylobacter species may have unique virulence factors that are expressed in the lower parts of the gastrointestinal tract.

Global Epidemiology of Campylobacter Infection

Campylobacter jejuni infection is one of the most widespread infectious diseases of the last century. The incidence and prevalence of campylobacteriosis have increased in both developed and developing countries over the last 10 years. The dramatic increase in North America, Europe, and Australia is alarming, and data from parts of Africa, Asia, and the Middle East indicate that campylobacteriosis is endemic in these areas, especially in children. In addition to C. jejuni, there is increasing recognition of the clinical importance of emerging Campylobacter species, including Campylobacter concisus and Campylobacter ureolyticus. Poultry is a major reservoir and source of transmission of campylobacteriosis to humans. Other risk factors include consumption of animal products and water, contact with animals, and international travel. Strategic implementation of multifaceted biocontrol measures to reduce the transmission of this group of pathogens is paramount for public health. Overall, campylobacteriosis is still one of the most important infectious diseases that is likely to challenge global health in the years to come. This review provides a comprehensive overview of the global epidemiology, transmission, and clinical relevance of Campylobacter infection.

Delineation of genetic relatedness and population structure of oral and enteric Campylobacter concisus strains by analysis of housekeeping genes

Campylobacter concisus is an oral bacterium that has been shown to be associated with inflammatory bowel disease (IBD). In this study we examined clusters of oral C. concisus strains isolated from patients with IBD and healthy controls by analysing six housekeeping genes. In addition, we investigated the population structure of C. concisus strains. Whether oral and enteric strains form distinct clusters based on the sequences of these housekeeping genes was also investigated. The oral C. concisus strains were found to contain two genomospecies, which belong to the two genomospecies previously found in enteric C. concisus strains. C. concisus clusters formed based on the sequences of a single aspA gene were the same as that formed by using previously reported MLST schemes. The analysis of combined oral and enteric C. concisus strains found that enteric C. concisus strains did not form distinct clusters. Genetic structure analysis identified five subpopulations of C. concisus and showed that genetic recombination between C. concisus strains was common. However, genetic recombination was significantly less in oral strains isolated from patients with IBD than from healthy individuals. Previously reported oral and enteric intestinal epithelial invasive C. concisus strains were in cluster II and subpopulation III. Furthermore, this study shows that there are no distinct enteric C. concisus strain clusters or subpopulations.