Occurrence of fastidious Campylobacter spp. in fresh meat and poultry using an adapted cultural protocol

Characterization of viable but nonculturable state of Campylobacter concisus

Campylobacter concisus is an opportunistic bacterial pathogen linked with a range of human diseases. The objective of this study was to investigate the viable but nonculturable (VBNC) state of the bacterium. To induce the VBNC state, C. concisus cells were maintained in sterilized phosphate-buffered saline at 4°C for three weeks. The VBNC cells were monitored using quantitative analysis by propidium monoazide (PMAxx) coupled with quantitative real-time PCR (PMAxx-qPCR), targeting the DNA gyrase subunit B gene. The results demonstrated that C. concisus ATCC 51562 entered the VBNC state in 15 days, while ATCC 51561 entered the VBNC state in 9 days. The viable cell counts, assessed by PMAxx-qPCR, consistently remained close to the initial level of 107 CFU ml-1, indicating a substantial portion of the cell population had entered the VBNC state. Notably, morphological analysis revealed that the VBNC cells became coccoid and significantly smaller. The cells could be resuscitated through a temperature increase in the presence of a highly nutritious growth medium. In conclusion, under environmental stress, most C. concisus cells converted to the VBNC state. The VBNC state of C. concisus may be important for its environmental survival and spread, and the presence of VBNC forms should be considered in environmental and clinical monitoring.

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.

Campylobacter majalis sp. nov. and Campylobacter suis sp. nov., novel Campylobacter species isolated from porcine gastrointestinal mucosa

Strains LMG 7974^T and LMG 8286^T represent single, novel Campylobacter lineages with Campylobacter pinnipediorum and Campylobacter mucosalis as nearest phylogenomic neighbours, respectively. The results of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) analyses of LMG 7974^T, LMG 8286^T and type strains of species of the genus Campylobacter confirmed that these strains represent novel species of the genus Campylobacter. The 16S rRNA gene sequences of both strains showed highest identity towards C. mucosalis (97.84 and 98.74 %, respectively). Strains LMG 7974^T and LMG 8286^T shared 72.5 and 73.7% ANI, respectively, with their nearest phylogenomic neighbours and less than 21 % dDDH. The draft genome sizes of LMG 7974^T and LMG 8286^T are 1 945429 bp and 1 708214 bp in length with percentage DNA G+C contents of 33.8 and 37.2 %, respectively. Anomalous biochemical characteristics and low MALDI-TOF mass spectrometry log scores supported their designation as representing novel species of the genus Campylobacte. We therefore propose to classify strain LMG 7974^T (=CCUG 20705^T) as the type strain of the novel species Campylobacter majalis sp. nov. and strain LMG 8286^T (=CCUG 24193^T, NCTC 11879^T) as the type strain of the novel species Campylobacter suis sp. nov.

Bacteriological Survey of Fresh Minced Beef on Sale at Retail Outlets in Scotland in 2019: Three Foodborne Pathogens, Hygiene Process Indicators, and Phenotypic Antimicrobial Resistance

ABSTRACT

The health and economic burden of foodborne illness is high, with approximately 2.4 million cases occurring annually in the United Kingdom. A survey to understand the baseline microbial quality and prevalence of food-related hazards of fresh beef mince on retail sale could inform risk assessment, management, and communication to ensure the safety of this commodity. In such a survey, a two-stage sampling design was used to reflect variations in population density and the market share of five categories of retail outlets in Scotland. From January to December 2019, 1,009 fresh minced beef samples were collected from 15 geographic areas. The microbial quality of each sample was assessed using aerobic colony count and Escherichia coli count. Samples were cultured for Campylobacter and Salmonella, and PCR was used to detect target genes (stx1 all variants, stx2 a to g, and rfbO157) for Shiga toxin-producing E. coli (STEC). The presence of viable E. coli O157 and STEC in samples with a positive PCR signal was confirmed via culture and isolation. Phenotypic antimicrobial sensitivity patterns of cultured pathogens and 100 E. coli isolates were determined, mostly via disk diffusion. The median aerobic colony count and E. coli counts were 6.4 × 105 (interquartile range, 6.9 × 104 to 9.6 × 106) and <10 CFU/g (interquartile range, <10 to 10) of minced beef, respectively. The prevalence was 0.1% (95% confidence interval [CI], 0 to 0.7%) for Campylobacter, 0.3% (95% CI, 0 to 1%) for Salmonella, 22% (95% CI, 20 to 25%) for PCR-positive STEC, and 4% (95% CI, 2 to 5%) for culture-positive STEC. The evidence for phenotypic antimicrobial resistance detected did not give cause for concern, mainly occurring in a few E. coli isolates as single nonsusceptibilities to first-line active substances. The low prevalence of pathogens and phenotypic antimicrobial resistance is encouraging, but ongoing consumer food safety education is necessary to mitigate the residual public health risk.

HIGHLIGHTS

Current methodologies and future direction of Campylobacter isolation and detection from food matrices, clinical samples, and the agricultural environment

Campylobacter spp. are the leading cause of bacterial foodborne infections in both developed and developing countries. The food commodities primarily attributed to campylobacteriosis include raw milk, poultry, seafood, and fresh produce. Furthermore, insects, animal/bird fecal material, and agricultural water have been shown to be the sources of Campylobacter contamination in these commodities. Both established and emerging species of Campylobacter have been recovered from food and environmental sources. Therefore, optimal detection and isolation of Campylobacter spp., including the emerging species, is critical for improved surveillance, prevention, and traceback of Campylobacter outbreaks. This review focuses on the existing variability in Campylobacter enrichment and isolation procedures used by researchers and regulatory agencies worldwide, for various matrices. Additionally, the challenges associated with developing and validating new culture, molecular, and immunological methods for rapid and sensitive Campylobacter detection are discussed.

Agents of Campylobacteriosis in Different Meat Matrices in Brazil

We aimed to identify the prevalence of thermophilic species of Campylobacter in meats of different species available on the Brazilian commercial market and to determine the genetic diversity, antimicrobial resistance and virulence potential of the isolates. A total of 906 samples, including chicken, beef and pork carcasses and chicken and beef livers, were purchased in retail outlets, and prevalences of 18.7% (46/246), 3.62% (5/138), 10.14% (14/138), 3.62% (5/138) and 4.47% (11/132), respectively, were identified, evidencing the dissemination of genotypes in the main producing macro-regions. Of all isolates, 62.8% were classified as multidrug resistant (MDR), with resistance to amoxicillin-clavulanate (49.4%), tetracycline (51.8%) and ciprofloxacin (50.6%) and co-resistance to macrolides and fluoroquinolones (37.1%). Multivirulent profiles were identified mainly in isolates from chicken carcasses (84.8%), and the emergence of MDR/virulent strains was determined in pork isolates. All isolates except those from chicken carcasses showed a high potential for biofilm formation (71.4% luxS) and consequent persistence in industrial food processing. For chicken carcasses, the general virulence was higher in C. jejuni (54.3%), followed by C. coli (24%) and Campylobacter spp. (21.7%), and in the other meat matrices, Campylobacter spp. showed a higher prevalence of virulence (57.2%). The high rates of resistance and virulence reinforce the existence of strain selection pressure in the country, in addition to the potential risk of strains isolated not only from chicken carcasses, but also from other meat matrices.

Characterization and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolated from chicken and pork

The prevalence and antimicrobial resistance (AMR) profile were investigated in Campylobacter jejuni and Campylobacter coli in chicken and pork in Fukuoka, Japan in 2019. Their AMR profiles were compared with those of C. jejuni and C. coli strains isolated in 2013. A total of 53 chicken and 14 pork samples were collected from different supermarkets in Fukuoka in 2019. Campylobacter spp. were isolated by conventional method and characterized by PCR and MALDI-TOF MS. Among 53 chicken samples tested in 2019, 24.5% and 5.7% were positive for C. jejuni and C. coli, respectively, and three (21.4%) of 14 pork samples were positive for C. coli, but not C. jejuni. From the positive samples, 13 and six strains of C. jejuni and C. coli were isolated, respectively. Antimicrobial susceptibility test against 12 different antimicrobials were performed on 48 isolates (43 C. jejuni and five C. coli) from chicken in 2013 and 19 isolates (13 C. jejuni from chicken, three C. coli from chicken and three C. coli from pork) in 2019 using the disk diffusion method. All the C. jejuni and C. coli isolated in 2013 and 2019 were highly resistant to cefazolin and sulfamethoxazole/trimethoprim. Among the C. jejuni isolates from chickens, 25.6% of 2013 isolates were resistant to nalidixic acid, ciprofloxacin, and levofloxacin, and 7% to ampicillin and minocycline, while 30.8% of the isolates were resistant to minocycline, 23.1% to nalidixic acid, ciprofloxacin, and levofloxacin, and 15.4% to ampicillin in 2019. Among the C. coli isolates, 80% of isolates from chickens in 2013, and 33.3% from chicken and 100% from pork in 2019 were resistant to nalidixic acid, ciprofloxacin, and levofloxacin. The frequency of multi-drug resistant (MDR) C. jejuni and C. coli strains from chickens in 2019 were 30.8% and 33.3%, respectively, which were lower than those isolated in 2013 (37.2% and 100%, respectively). One C. jejuni and two C. coli isolates from 2013 were resistant to six antibiotics. However, two C. jejuni and one C. coli isolate from chickens in 2019 were resistant to seven and five antibiotics, respectively. All the C. coli isolates from pork in 2019 were resistant to five antibiotics. The high frequency of AMR strains in C. coli isolates from pork suggests that appropriate use of antimicrobials is required in swine husbandry.

Enrichment Free qPCR for Rapid Identification and Quantification of Campylobacter jejuni, C. coli, C. lari, and C. upsaliensis in Chicken Meat Samples by a New Couple of Primers

Campylobacter is the main cause of bacterial foodborne disease and poultry meat is the principal source of human infections. Rapid methods for Campylobacter detection are urgently needed to decrease high bacterial prevalence in poultry products. In this study, we developed new primers, CampyPFw and CampyPRv, that target the 16S-23S rRNA genes of Campylobacter jejuni, C. coli, C. lari and C. upsaliensis. The primers were tested on positive and negative reference strains in pure cultures and in inoculated poultry meat samples before their application in real-time PCR (qPCR) protocol for analyzing chicken meat samples. In parallel, the samples were tested by using the ISO 10272-1:2006 method. The qPCR protocol based on CampyPFw and CampyPRv showed good sensitivity, with the limit of detection of 4.6 × 10² cells/mL in chicken samples without enrichment steps.

Comparison of the Pathogenic Potential of Campylobacter jejuni, C. upsaliensis and C. helveticus and Limitations of Using Larvae of Galleria mellonella as an Infection Model

Campylobacter enteritis in humans is primarily associated with C. jejuni/coli infection. Other species cause campylobacteriosis relatively infrequently; while this could be attributed to bias in diagnostic methods, the pathogenicity of non-jejuni/coli Campylobacter spp. such as C. upsaliensis and C. helveticus (isolated from dogs and cats) is uncertain. Galleria mellonella larvae are suitable models of the mammalian innate immune system and have been applied to C. jejuni studies. This study compared the pathogenicity of C. jejuni, C. upsaliensis, and C. helveticus isolates. Larvae inoculated with either C. upsaliensis or C. helveticus showed significantly higher survival than those inoculated with C. jejuni. All three Campylobacter species induced indistinguishable histopathological changes in the larvae. C. jejuni could be isolated from inoculated larvae up to eight days post-inoculation whereas C. upsaliensis and C. helveticus could only be isolated in the first two days. There was a significant variation in the hazard rate between batches of larvae, in Campylobacter strains, and in biological replicates as random effects, and in species and bacterial dose as fixed effects. The Galleria model is applicable to other Campylobacter spp. as well as C. jejuni, but may be subject to significant variation with all Campylobacter species. While C. upsaliensis and C. helveticus cannot be considered non-pathogenic, they are significantly less pathogenic than C. jejuni.

Species distribution, genetic diversity and antimicrobial susceptibility of Campylobacter isolates recovered from the preputial cavity of healthy rams in Turkey

AIMS

Campylobacter sp. are important causes of reproductive disease in ruminants worldwide. Although healthy bulls are well-known carriers for infection of cows, the role of rams as a potential source for infecting ewes is unclear. This study aimed to determine prevalence, species distribution, genetic diversity and antimicrobial susceptibility profiles of Campylobacter sp. isolated from the preputial cavity of healthy rams.

METHODS AND RESULTS

The material of this prospective study comprised 191 swab samples taken from the preputial cavity of healthy rams. Enrichment and membrane filtration were employed for the isolation of Campylobacter. Presumptive isolates were confirmed as Campylobacter by phenotypic and molecular tests. 16S rRNA gene sequence analysis was used for the definitive identification of the isolates at species level, and genotyping was performed using pulsed-field gel electrophoresis (PFGE). The susceptibility of the Campylobacter sp. isolates to various antibiotics was determined by the disk diffusion test. In all, 27 of the 191 (14·13%) swab samples were found to be positive for Campylobacter sp. (28 isolates were recovered in total). Per phenotypic and genotypic analyses, one isolate was identified as Campylobacter mucosalis and the remaining 27 isolates were identified as Campylobacter sputorum bv. faecalis. The PFGE analysis of the C. sputorum biovar faecalis isolates produced 17 clusters and 24 different pulsotypes, indicating high genetic heterogeneity. All 28 isolates were found to be susceptible to all of the antibiotics tested.

CONCLUSIONS

Healthy rams may be an important reservoir of different Campylobacter species in the preputium.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated for the first time that healthy rams can carry different Campylobacter sp. including genetically diverse C. sputorum bv. faecalis and C. mucosalis in the preputial cavity. Further investigation on the potential implication of this finding on sheep reproductive health (e.g. infectious infertility, and abortion) and overall epidemiology of Campylobacter may be warranted.

Prevalence, antibiotic resistance and genotypes of Campylobacter jejuni and Campylobacter coli isolated from chickens in Irbid governorate, Jordan

Campylobacter is the world's leading cause of bacterial gastroenteritis, causing nearly 9 million cases of food poisoning in Europe every year. Poultry is considered the main source of Campylobacter infection to humans. The objectives of the study were to determine occurrence of C. jejuni and C. coli in chickens, the antimicrobial resistance, genotypes, and relatedness of the isolates. A total of 177 chicken samples obtained from informal butcher shops (fresh), formal poultry slaughterhouses (refrigerated) and retail market (frozen) were analyzed. Isolation of Campylobacter spp. was conducted according to the ISO 10272-2006 method. Multiplex PCR was used for confirmation and identification of the isolates. The disk diffusion method was used to determine the antimicrobial resistance of the isolates and multilocus sequence typing was used for genotyping. The proportion of samples with Campylobacter spp. was 31.6% among all chicken samples (fresh and refrigerated 47.5%, frozen 0%) C. coli was isolated from 42.4% of chicken samples obtained from butcher shops and from 18.6% of samples obtained in formal slaughterhouses. C. jejuni was isolated from 17.0% of samples obtained in butcher shops and formal slaughterhouses. Campylobacter spp. was not isolated in frozen chicken samples. All tested isolates showed resistance toward ciprofloxacin and susceptibility toward imipenem and all of the isolates were multidrug resistant toward 5 or more antimicrobials. Three sequence types were identified among 10 C. coli isolates and seven sequence types were identified among 10 C. jejuni isolates. Among sequence types, chicken isolates shared similarities of both phenotypic and genetic levels.

Occurrence and Antimicrobial Resistance Profiles of Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis in Beef Cattle on Cow-Calf Operations in South Africa

This study investigated occurrence and antimicrobial resistance profiles of Campylobacter spp. isolates in beef cattle on five cow-calf operations in South Africa. A total of 537 fecal samples from adult beef cattle (n = 435) and rectal swabs from calves (n = 102) were screened for Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis by culture and polymerase chain reaction. Furthermore, 86 Campylobacter spp. isolates including 46 C. jejuni, 24 C. coli, and 16 C. upsaliensis were tested for antimicrobial resistance against a panel of 9 antimicrobials. Overall, Campylobacter spp. was detected in 29.7% of cattle. Among the 158 Campylobacter spp.-positive cattle, 61.8% carried C. jejuni, 25% carried C. coli, and 10% carried C. upsaliensis. Five animals (3.1%) had mixed infections: three cows carried C. jejuni and C. coli concurrently, one cow had both C. jejuni and C. upsaliensis, and one cow harbored C. coli and C. upsaliensis. Antimicrobial resistance profiling among 86 Campylobacter spp. isolates revealed that 52.3% of the isolates were resistant to one or more antimicrobials. Antimicrobial resistance was observed in 46.7% of C. jejuni isolates, 35.6% of C. coli, and 17.8% of C. upsaliensis. Thirty-six percent of isolates were resistant to clindamycin, 19.7% to nalidixic acid, 18.6% to tetracycline, and 17.4% to erythromycin. Lower resistance rates were recorded for azithromycin (8.1%), florfenicol (3.4%), gentamicin (4.8%), and telithromycin and ciprofloxacin (5.8%). Multidrug resistance (MDR) was observed in 32.5% of isolates. Significantly higher levels of MDR were detected among C. jejuni (36.9%) and C. coli (33.3%) isolates in comparison to C. upsaliensis (18.7%). Two main multiresistance patterns were detected: nalidixic acid/clindamycin (17.8%) and tetracycline/clindamycin (14.2%). To the best of our knowledge, this is the first study which has shown that beef cattle on cow-calf operations in South Africa constitute an important reservoir and a potential source of clinically relevant and antimicrobial resistant Campylobacter spp. strains.

Isolation of emerging Campylobacter species in working farm dogs and their frozen home-killed raw meat diets

We applied 7 culture methods to 50 working farm dog fecal samples and 6 methods to 50 frozen home-killed raw meat diet samples to optimize recovery of a wide range of Campylobacter spp. Culture methods combined filtration, enrichment broths, and agars at 37°C and 42°C in conventional and hydrogen-enriched microaerobic atmospheres. Overall, a prevalence of 62% (31 of 50) and 6% (3 of 50) was detected in dog and meat samples, respectively, based on Campylobacter genus PCR. A total of 356 Campylobacter spp. isolates were recovered from dogs, with successful isolation by individual methods ranging from 2 to 25 dogs. The species detected most commonly were C. upsaliensis and C. jejuni, and less commonly C. coli and C. lari. Species isolated that are rarely reported from dogs included C. rectus, C. lari subsp. concheus, C. volucris, and Helicobacter winghamensis. Six isolates from dogs positive by Campylobacter genus PCR were confirmed, using 16S rRNA sequencing, as Arcobacter cryaerophilus (1) and Arcobacter butzleri (5). C. jejuni multi-locus sequence typing results revealed a diversity of sequence types in working dogs, with several uncommonly reported from other C. jejuni sources in New Zealand. Overall, 20 isolates from 3 meat samples were positive by Campylobacter genus PCR; 1 meat sample was positive for C. jejuni, 1 for C. rectus, and 1 isolate was subsequently identified as A. butzleri. The method using Campylobacter enrichment broth in a hydrogen-enriched environment on nonselective agar resulted in significantly reduced recovery of Campylobacter spp. from both sample types.

Comparison of the Filtration Culture and Multiple Real-Time PCR Examination for Campylobacter spp. From Stool Specimens in Diarrheal Patients

Campylobacter is one of the most common pathogens leading to the bacterial diarrheal illness. In order to set up one effective culture independent assay for the screen of the Campylobacter infection in the diarrheal patients, the quadruple real-time PCR method comparing to the culture based on the enriched filtration method which was recognized as the most effective isolation method was assessed for 190 stool samples from the diarrheal patients collected during the Foodborne Diseases Active Surveillance Network in Beijing. This multiple real-time PCR was designed to identify the Campylobacter genus, C. jejuni, C. coli, and C. lari simultaneously. With the enrichment culture method, 23 (12.1%, 23/190) Campylobacter isolates were obtained (20 C. jejuni and 3 C. coli), however, 31 samples (16.3%, 31/190) were detected positively with the real-time PCR (21 C. jejuni, 8 C. coli, and 2 Campylobacter genus only). With the comparison, the real-time-PCR method is more sensitive than the enrichment filtration method (16.3 vs. 12.1%, p = 0.021). Among the culture-positive samples, 95.7% (22/23) were detected positively by PCR which indicate the specificity of this method was higher. These two methods were consistent well (Kappa = 0.785, p < 0.05). Comparing to the culture methods, the result of the multiple real-time PCR method is sensitive, reliable and rapid. The present study indicated this multiple real-time PCR can be used both for the surveillance network and the preceding screen for bacteria isolation. This is first comparative study between the culture and multiple real-time PCR method for Campylobacter identification in stool specimens from the diarrheal patients.

Pulmonary Campylobacter concisus infection in an immunocompromised patient with underlying mucormycosis

Campylobacter concisus is a rarely encountered agent of human infection. The first isolation of C. concisus from a pulmonary abscess in an immunocompromised patient who underwent allogeneic stem cell transplantation is reported here. This unusual case demonstrates the pathogenic potential of this bacterium and outlines species-immanent difficulties in gaining a reliable diagnosis. Molecular methods were a cornerstone for definite identification of the organism grown on anaerobic culture from surgically excised tissue. Antimicrobial susceptibility testing revealed unusual quinolone and macrolide resistance, and therefore antimicrobial therapy was based on β-lactam antibiotics.

Occurrence of Campylobacter in retail meat in Lahore, Pakistan

Campylobacter, one of the emerging zoonotic pathogens, is worldwide in distribution. This thermo-tolerant pathogen is one of the leading causes of diarrhea and gastroenteritis in humans. The main sources of infection are contaminated meat and meat products. A cross-sectional study was conducted to estimate the prevalence of Campylobacter species in retail meat in the Lahore district of Pakistan from September 2014 to January 2015. A total of 600 samples (200 samples each of beef, mutton, and chicken) were collected from retail shops through convenience sampling and preceded for Campylobacter contamination using the ISO 10272-1:2006 (E) method. Campylobacter was present in all three types of meat; the highest prevalence being recorded in chicken meat (29%) followed by mutton (18%) and beef (15.5%). Campylobacters were isolated from 125 (20.8%) samples out of the 600 meat samples. Campylobacter jejuni was more common (74.4%) than C. coli (25.6%). The highest number of Campylobacters were isolated in September (25/125) and November (23/125) while low numbers were isolated in October and December with isolates rate of (17/125) and (19/125), respectively. The highest prevalence was seen in the oldest and overpopulated town of Data Gunj Bakhsh 16% (20/125) while lowest prevalence was seen in a newer and least populated town of Gulburg (7/125). These results indicate that Campylobacter species are circulating in various meat sources in Lahore and that it may pose a threat to public health.

A Review of the Effect of Management Practices on Campylobacter Prevalence in Poultry Farms

Poultry is frequently associated with campylobacteriosis in humans, with Campylobacter jejuni being the most usual Campylobacter associated with disease in humans. Far-reaching research on Campylobacter was undertaken over the past two decades. This has resulted in interventions being put in place on farms and in processing plants. Despite these interventions, coupled with increased media coverage to educate the consumer on Campylobacter prevalence and campylobacteriosis, human health incidents are still high. Recent research is now shifting toward further understanding of the microorganisms to challenge interventions in place and to look at further and more relevant interventions for the reduction in human incidents. Farm practices play a key role in the control of colonization within poultry houses and among flocks. Prevalence at the farm level can be up to 100% and time of colonization may vary widely between flocks. Considerable research has been performed to understand how farm management and animal health practices can affect colonization on farms. This review will focus on farm practices to date as a baseline for future interventions as the microorganism becomes better understood. Further research is required to understand the chicken microbiome and factors influencing vertical transmission. The persistence of Campylobacter in animal and environmental reservoirs within and around farms requires further investigation to tailor farm practices toward preventing such reservoirs. IMPLICATIONS  This review gives an overview of farm practices and their effect on Campylobacter prevalence in poultry. Various elements of farm practices have been captured in this review.

Prevalence and risk factors for thermotolerant species of Campylobacter in poultry meat at retail in Europe

The thermotolerant species Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter upsaliensis are the causative agents of the human illness called campylobacteriosis. This infection represents a threat for the health of consumers in Europe. It is well known that poultry meat is an important food vehicle of Campylobacter infection. As emerged from the reported scientific literature published between 2006 and 2016, poultry meat sold at retail level in Europe represents an important source of the pathogen. The contamination level of poultry meat sold at retail can vary depending on pre- and post-harvest factors. Among the pre-harvest measures, strict biosecurity practices must be guaranteed; moreover, among post-harvest control measures scalding, chilling and removal of faecal residues can reduce the contamination level of Campylobacter. An additional issue is represented by increasing proportion of Campylobacter isolates resistant to tetracyclines, ciprofloxacin, and nalidixic acid, thus feeding a serious concern on the effectiveness of antibiotic treatment for human campylobacteriosis in a near future.

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.

Prevalence and Molecular Characterization of Campylobacter spp. Isolated from Patients with Diarrhea in Shunyi, Beijing

Bacterial pathogens have been confirmed as the major cause of acute diarrhea among outpatients in China. In this study, 370 stool samples from the patients aged from 15 to 87 years old with diarrhea were collected over 12 months (from May 2016 to April 2017) in two hospitals in Shunyi, Beijing. Bacterial isolation was performed for the common enteric pathogens: Campylobacter, Salmonella, Shigella, Diarrheagenic Escherichia coli, and Vibrio parahaemolyticus for 370 samples. The filtration method was used for the Campylobacter isolation in this study. The prevalence and molecular characterization of the Campylobacter were investigated. The isolation ratio for Campylobacter, Salmonella, Shigella, Diarrheagenic E. coli, and V. parahaemolyticus was 7.0% (26/370), 6.2% (23/370), 0.3% (1/370), 7.3% (27/370), and 10.3% (38/370), respectively. Based on the isolation result, Campylobacter positive cases presented in almost every month of the whole year and the isolation ratio was the highest among the tested pathogens during October to March. There was no significant difference between genders of Campylobacter positive cases. More Campylobacter positive cases presented dehydration compared with those who were positive for Salmonella. Twenty-six Campylobacter isolates were obtained in this study and 24 of these were Campylobacter jejuni. The antibiotic susceptibility tests indicated that 83.3% (20/24) of the isolates exhibited resistance to three or more types of antibiotic. Twenty STs were identified for the 26 Campylobacter isolates and four novel STs were identified in this study. No clonal cluster was found among these isolates. This is the first study for Campylobacter isolated using the filtration method in China which indicated the Campylobacter infection might be seriously under-ascertained in the diarrheal patients in China.

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.

Influence of measurement and control of microaerobic gaseous atmospheres in methods for Campylobacter growth studies

Campylobacter is the leading cause of bacterial enteritis in the world. For this reason, this pathogen is widely studied. As a microaerophilic and capnophilic microorganism, this foodborne pathogen requires an atmosphere with reduced oxygen (O2) and elevated carbon dioxide (CO2) concentrations for its optimal growth in vitro. According to the procedure for Campylobacter spp. isolation and cultivation from food products and environmental samples, European and American standards recommend gas proportions of 5% O2 and 10% CO2, complemented with nitrogen (N2). However, in the literature, the reported proportion of O2 for microaerobic growth conditions of Campylobacter spp. can range from 2.5% to 15% and the reason for this variation is usually not explained. The use of different gas generating systems and media to detect and to grow Campylobacter from foodstuff and the lack of information about gas producing systems are the main sources of the loss of consistancy between data. In this review, the relevance, strengths and weaknesses of these methods and their impact on Campylobacter biology are discussed. In conclusion the minimum information concerning microaerobic gaseous atmospheres are suggested in order to better harmonize data obtained from research studies for a better understanding of Campylobacter features.

Prevalence of Campylobacter spp. in Retail Chicken, Turkey, Pork, and Beef Meat in Poland between 2009 and 2013

The purpose of the present study was to determine the prevalence of thermophilic Campylobacter in poultry, pork, and beef meat at the retail level and to identify the main categories of meat representing the most significant reservoirs of Campylobacter. A monitoring study was conducted throughout Poland from 2009 to 2013. A total of 1,700 fresh meat samples were collected from supermarkets, large retail outlets, and smaller stores. Thermophilic Campylobacter species were detected in 690 (49.3%) of 1,400 poultry samples collected from retail trade. Strains were isolated from 50.2 and 41.1% of raw chicken and turkey meat samples, respectively, and from 50.1 and 42.6% of raw chicken and turkey giblets. The incidence of Campylobacter spp. on pork (10.6%) and beef (10.1%) was significantly lower than on poultry. Campylobacter jejuni was the most prevalent Campylobacter species in chicken (46.6%), pork (68.6%), and beef (66.7%), and Campylobacter coli was the most frequently isolated Campylobacter species in turkey meat (71.2%). This study revealed that retail raw meats are often contaminated with Campylobacter; however, the prevalence of these pathogens is markedly different in different meats. Raw retail meats are potential vehicles for transmitting foodborne diseases, and our findings stress the need for increased implementation of hazard analysis critical control point programs and consumer food safety education efforts.

Prevalence and diversity of Campylobacter species in Saskatchewan retail ground beef

The primary objective of this study was to investigate the prevalence of Campylobacter spp. DNA by PCR in retail ground beef sold in Saskatchewan, Canada, and to identify the presence of individual Campylobacter species (C. coli, C. curvus, C. fetus, C. hyointestinalis, C. jejuni, C. rectus, and C. upsaliensis) using real-time quantitative PCR (qPCR). Secondary objectives were to assess potential differences in the prevalence of Campylobacter between ground beef offered for sale during cold and warm seasons as well as that offered for sale fresh and frozen, to investigate any association between the presence of Campylobacter spp. DNA and E. coli and/or aerobic bacterial counts, and finally to compare the prevalence of Campylobacter spp. DNA in ground beef originating from different production and retail environments. Out of the 309 total samples included in the study, 50 (16.2%) samples tested positive for Campylobacter spp. DNA, while 49 (15.9%) samples were determined positive for up to five individual species. Collectively, these assays determined that 14 (4.5%) samples were positive for C. coli, 11 (3.6%) for C. curvus, 6 (1.9%) for C. fetus, 24 (7.8%) for C. hyointestinalis, 12 (3.9%) for C. jejuni, 6 (1.9%) for C. rectus, and 9 (2.9%) for C. upsaliensis. There were 27 (8.7%) samples that were positive at the genus level that did not test positive for any of the seven Campylobacter species investigated (suggesting an alternate Campylobacter species). Also, 26 (8.4%) samples generated positive results by one of the species-specific qPCR assays, but returned no product in the conventional genus-level assay (suggesting a higher sensitivity for the species-specific qPCR assays). There was no significant association between the presence of Campylobacter spp. in Saskatchewan retail ground beef and any of the investigated risk factors.

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

BACKGROUND

Poultry 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.

METHODS

In 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.

RESULTS

The 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.

CONCLUSION

Depletion 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.

Rapid detection and differentiation of important Campylobacter spp. in poultry samples by dot blot and PCR

The detection of Campylobacter, the most commonly reported cause of foodborne gastroenteritis in the European Union, is very important for human health. The most commonly recognised risk factor for infection is the handling and/or consumption of undercooked poultry meat. The methods typically applied to evaluate the presence/absence of Campylobacter in food samples are direct plating and/or enrichment culture based on the Horizontal Method for Detection and Enumeration of Campylobacter spp. (ISO 10272-1B: 2006) and PCR. Molecular methods also allow for the detection of cells that are viable but cannot be cultivated on agar media and that decrease the time required for species identification. The current study proposes the use of two molecular methods for species identification: dot blot and PCR. The dot blot method had a sensitivity of 25 ng for detection of DNA extracted from a pure culture using a digoxigenin-labelled probe for hybridisation; the target DNA was extracted from the enrichment broth at 24 h. PCR was performed using a pair of sensitive and specific primers for the detection of Campylobacter jejuni and Campylobacter coli after 24 h of enrichment in Preston broth. The initial samples were contaminated by 5 × 10 C. jejuni cells/g and 1.5 × 10(2)C. coli cells/g, thus the number of cells present in the enrichment broth at 0 h was 1 or 3 cell/g, respectively.

Campylobacter concisus and 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.

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

Campylobacterconcisus 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.

The effects of oral and enteric Campylobacter concisus strains on expression of TLR4, MD-2, TLR2, TLR5 and COX-2 in HT-29 cells

Campylobacter concisus, a Gram-negative bacterium that colonizes the human oral cavity, has been shown to be associated with inflammatory bowel diseases (IBD). The effects of different C. concisus strains on intestinal epithelial expression of Toll like receptors (TLR) have not been investigated. This study examined the effects of C. concisus strains isolated from patients with IBD and controls on expression of TLR4, its co-receptor myeloid differentiation factor (MD)-2; TLR2, TLR5, cyclooxygenase-2 (COX-2) and interleukin (IL)-8 in HT-29 cells.Fourteen oral and enteric C. concisus strains isolated from patients with IBD and healthy controls were co-incubated with HT-29 cells. Expression of TLR4, MD-2, TLR2, TLR5 and COX-2 in HT-29 cells in response to C. concisus infection was examined by Western blot, flow cytometry analysis and immunofluorescent staining visualized by confocal microscope. Production of IL-8 was evaluated by enzyme-linked immunosorbent assay.Both oral and enteric C. concisus strains upregulated expression of TLR4 in HT-29 cells. The levels of glycosylated TLR4 (Gly-TLR4) and surface TLR4 induced by C. concisus strains isolated from patients with IBD were significantly higher than those induced by C. concisus strains isolated from the healthy controls. Four C. concisus strains isolated from patients with IBD induced more than two-fold increase of surface expression of MD-2. C. concisus did not affect expression of TLR2 and TLR5. All C. concisus strains induced production of IL-8 and COX-2 in HT-29 cells.This study shows that some C. concisus strains, most from patients with IBD, upregulate surface expression of TLR4 and MD-2 in HT-29 cells. These data suggest that a potential role of specific C. concisus strains in modulating the intestinal epithelial responses to bacterial LPS needs to be investigated.

Occurrence and characteristics of fastidious Campylobacteraceae species in porcine samples

This study investigated the prevalence and characteristics of Campylobacteraceae including a range of fastidious species in porcine samples. Over a thirteen month period caecal contents (n=402) and pork carcass swabs (n=401) were collected from three pork abattoirs and pork products (n=399) were purchased at point of sale in the Republic of Ireland. Campylobacteraceae isolates were recovered by enrichment, membrane filtration and incubation in antibiotic free media under a modified atmosphere (3% O2, 5% H2, 10% CO2 and 82% N2). Campylobacteraceae isolates were identified as either genus Campylobacter or Arcobacter and then selected species were identified by Polymerase Chain Reaction (PCR). Campylobacteraceae were isolated from 103 (26%) caecal samples, 42 (10%) carcass swabs, and 59 (15%) pork products. Campylobacter coli was the most commonly isolated species found in (37%) all sample types but many fastidious species were also isolated including Campylobacter concisus (10%), Arcobacter butzleri (8%), Campylobacter helveticus (8%), Campylobacter mucosalis (6%), Arcobacter cryaerophilus (3%), Campylobacter fetus subsp. fetus (1%), Campylobacter jejuni subsp. jejuni (1%), Campylobacter lari (0.5%), Campylobacter curvus (0.5%) and Arcobacter skirrowii (0.5%). Among all isolates, 83% contained cadF and 98% flaA. In this study 35% of porcine C. coli were resistant to ciprofloxacin but none of the fastidious species demonstrated any resistance to this drug. The level of resistance to erythromycin was very high (up to 100%) in C. concisus and C. helveticus and this is a real concern as this is the current empiric drug of choice for treatment of severe gastroenteritic Campylobacter infections. The study shows that there is a much wider range of fastidious Campylobacteraceae present in porcine samples than previously assumed with C. concisus the second most common species isolated. The majority of fastidious Campylobacteraceae isolates obtained contained virulence genes and antibiotic resistance indicating potential public health significance.

Investigation of the enteric pathogenic potential of oral Campylobacter concisus strains isolated from patients with inflammatory bowel disease

Background

Campylobacter concisus, a bacterium colonizing the human oral cavity, has been shown to be associated with inflammatory bowel disease (IBD). This study investigated if patients with IBD are colonized with specific oral C. concisus strains that have potential to cause enteric diseases.

Methodology

Seventy oral and enteric C. concisus isolates obtained from eight patients with IBD and six controls were examined for housekeeping genes by multilocus sequence typing (MLST), Caco2 cell invasion by gentamicin-protection-assay, protein analysis by mass spectrometry and SDS-PAGE, and morphology by scanning electron microscopy. The whole genome sequenced C. concisus strain 13826 which was isolated from an individual with bloody diarrhea was included in MLST analysis.

Principal Findings

MLST analysis showed that 87.5% of individuals whose C. concisus belonged to Cluster I had inflammatory enteric diseases (six IBD and one with bloody diarrhea), which was significantly higher than that in the remaining individuals (28.6%) (P<0.05). Enteric invasive C. concisus (EICC) oral strain was detected in 50% of patients with IBD and none of the controls. All EICC strains were in Cluster 1. The C. concisus strain colonizing intestinal tissues of patient No. 1 was closely related to the oral C. concisus strain from patient No. 6 and had gene recombination with the patient’s own oral C. concisus. The oral and intestinal C. concisus strains of patient No. 3 were the same strain. Some individuals were colonized with multiple oral C. concisus strains that have undergone natural recombination.

Conclusions

This study provides the first evidence that patients with IBD are colonized with specific oral C. concisus strains, with some being EICC strains. C. concisus colonizing intestinal tissues of patients with IBD at least in some instances results from an endogenous colonization of the patient’s oral C. concisus and that C. concisus strains undergo natural recombination.

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

The incidence of non-thermophilic Campylobacter species was assessed in an unselected population-based study in a mixed urban and rural community in North Jutland, Denmark. In a 2-year study period, 11,314 faecal samples from 8302 patients with gastroenteritis were cultured with supplement of the filter method. We recovered a high incidence of Campylobacter concisus (annual incidence 35/100,000 inhabitants), almost as high as the common Campylobacter jejuni/coli. In contrast, there was a very low incidence of other non-thermophilic Campylobacter species, such as Campylobacter upsaliensis. Campylobacter concisus was, unlike C. jejuni/coli, found more frequently among small children (<1 year) and the elderly (≥ 65 years). Around 10% of the patients with C. consisus had co-infections dominated by Clostridium difficile and Salmonella enterica, whereas co-infections occurred in about 5% of C. jejuni/coli patients. We observed a seasonal variation in C. jejuni/coli with a peak incidence in late summer months and autumn, whereas there was an almost constant monthly prevalence of C. concisus. Among patients participating in a questionnaire sub-study, there was a higher degree of close contacts with animals, especially dogs, as well as a higher travel exposure among C. jejuni/coli patients compared with C. concisus patients. We did not culture any C. concisus in stool samples from a small cohort of healthy individuals. Future studies have to focus on the clinical follow-up and the long-term risk of inflammatory bowel diseases in C. concisus-positive patients. We conclude that there is a high incidence of C. concisus in Denmark.

Multilocus sequence typing methods for the emerging Campylobacter Species C. hyointestinalis, C. lanienae, C. sputorum, C. concisus, and C. curvus

Multilocus sequence typing (MLST) systems have been reported previously for multiple food- and food animal-associated Campylobacter species (e.g., C. jejuni, C. coli, C. lari, and C. fetus) to both differentiate strains and identify clonal lineages. These MLST methods focused primarily on campylobacters of human clinical (e.g., C. jejuni) or veterinary (e.g., C. fetus) relevance. However, other, emerging, Campylobacter species have been isolated increasingly from environmental, food animal, or human clinical samples. We describe herein four MLST methods for five emerging Campylobacter species: C. hyointestinalis, C. lanienae, C. sputorum, C. concisus, and C. curvus. The concisus/curvus method uses the loci aspA, atpA, glnA, gltA, glyA, ilvD, and pgm, whereas the other methods use the seven loci defined for C. jejuni (i.e., aspA, atpA, glnA, gltA, glyA, pgm, and tkt). Multiple food animal and human clinical C. hyointestinalis (n = 48), C. lanienae (n = 34), and C. sputorum (n = 24) isolates were typed, along with 86 human clinical C. concisus and C. curvus isolates. A large number of sequence types were identified using all four MLST methods. Additionally, these methods speciated unequivocally isolates that had been typed ambiguously using other molecular-based speciation methods, such as 16S rDNA sequencing. Finally, the design of degenerate primer pairs for some methods permitted the typing of related species; for example, the C. hyointestinalis primer pairs could be used to type C. fetus strains. Therefore, these novel Campylobacter MLST methods will prove useful in differentiating strains of multiple, emerging Campylobacter species.

Campylobacter concisus - A new player in intestinal disease

Over the last decade Campylobacter concisus, a highly fastidious member of the Campylobacter genus has been described as an emergent pathogen of the human intestinal tract. Historically, C. concisus was associated with the human oral cavity and has been linked with periodontal lesions, including gingivitis and periodontitis, although currently its role as an oral pathogen remains contentious. Evidence to support the role of C. concisus in acute intestinal disease has come from studies that have detected or isolated C. concisus as sole pathogen in fecal samples from diarrheic patients. C. concisus has also been associated with chronic intestinal disease, its prevalence being significantly higher in children with newly diagnosed Crohn’s disease (CD) and adults with ulcerative colitis than in controls. Further C. concisus has been isolated from biopsy specimens of patients with CD. While such studies support the role of C. concisus as an intestinal pathogen, its isolation from healthy individuals, and failure of some studies to show a significant difference in C. concisus prevalence in subjects with diarrhea and healthy controls has raised contention as to its role in intestinal disease. Such findings could argue against the role of C. concisus in intestinal disease, however, the fact that C. concisus strains are genetically diverse raises the possibility that differences exist in their pathogenic potential. Evidence to support this view comes from studies showing strain specific differences in the ability of C. concisus to attach to and invade cells and produce virulence factors, including toxins and hemolytic phospholipase A. Further, sequencing of the genome of a C. concisus strain isolated from a child with CD (UNSWCD) and comparison of this with the only other fully sequenced strain (BAA-1457) would suggest that major differences exist in the genetic make-up of this species which could explain different outcomes of C. concisus infection.

The clinical importance of emerging Campylobacter species

A growing number of Campylobacter species other than C. jejuni and C. coli have been recognized as emerging human and animal pathogens. Although C. jejuni continues to be the leading cause of bacterial gastroenteritis in humans worldwide, advances in molecular biology and development of innovative culture methodologies have led to the detection and isolation of a range of under-recognized and nutritionally fastidious Campylobacter spp., including C. concisus, C. upsaliensis and C. ureolyticus. These emerging Campylobacter spp. have been associated with a range of gastrointestinal diseases, particularly gastroenteritis, IBD and periodontitis. In some instances, infection of the gastrointestinal tract by these bacteria can progress to life-threatening extragastrointestinal diseases. Studies have shown that several emerging Campylobacter spp. have the ability to attach to and invade human intestinal epithelial cells and macrophages, damage intestinal barrier integrity, secrete toxins and strategically evade host immune responses. Members of the Campylobacter genus naturally colonize a wide range of hosts (including pets, farm animals and wild animals) and are frequently found in contaminated food products, which indicates that these bacteria are at risk of zoonotic transmission to humans. This Review presents the latest information on the role and clinical importance of emerging Campylobacter spp. in gastrointestinal health and disease.