Campylobacter subantarcticus sp. nov., isolated from birds in the sub-Antarctic region

Campylobacter jejuni/coli Infection: Is It Still a Concern?

Campylobacteriosis is a leading cause of infectious diarrhea and foodborne illness worldwide. Campylobacter infection is primarily transmitted through the consumption of contaminated food, especially uncooked meat, or untreated water; contact with infected animals or contaminated environments; poultry is the primary reservoir and source of human transmission. The clinical spectrum of Campylobacter jejuni/coli infection can be classified into two distinct categories: gastrointestinal and extraintestinal manifestations. Late complications are reactive arthritis, Guillain-Barré syndrome, and Miller Fisher syndrome. In the pediatric population, the 0-4 age group has the highest incidence of campylobacteriosis. Regarding the use of specific antimicrobial therapy, international guidelines agree in recommending it for severe intestinal infections. Host factors, including malnutrition, immunodeficiency, and malignancy, can also influence the decision to treat. The Centers for Disease Control and Prevention (CDC) has identified antibiotic resistance in Campylobacter as a 'significant public health threat' due to increasing resistance to FQs or macrolides. Although numerous vaccines have been proposed in recent years to reduce the intestinal colonization of poultry, none have shown sufficient efficacy to provide a definitive solution.

Phenotypic and Genomic Characteristics of Campylobacter gastrosuis sp. nov. Isolated from the Stomachs of Pigs in Beijing

Campylobacter is among the four main causes of gastroenteritis worldwide. Most reported Campylobacter infections are caused by C. jejuni and C. coli. However, other emerging Campylobacter pathogens have been recognized as important pathogens in humans and animals. A novel bacterial strain, PS10T, was isolated from the gastric mucous of pigs in 2022 in Beijing, China. The cell was Gram-negative, microaerobic, motile, and negative for catalase, oxidase, and urease. Phylogenetic and phylogenomic analyses based on the 16S rRNA gene and core genome indicated that this isolate belongs to the genus Campylobacter. There were low dDDH relatedness and ANI values shared within this strain and its closest species C. mucosalis below the cut-off values generally recognized for isolates of the same species. The draft genome size of PS10T is 2,240,910 bp in length with a percentage of DNA G+C contents of 37.72%. Comparing the phenotypic and phylogenetic features among this isolate and its related organisms, strain PS10T represents a novel species within the genus Campylobacter, for which the name Campylobacter gastrosuis sp. nov. (Type strain PS10T = GDMCC 1.3686T = JCM 35849T) is proposed.

A Systematic Review on the Role of Wildlife as Carriers and Spreaders of Campylobacter spp

Campylobacter spp. are important zoonotic pathogens and can cause one of the main bacterial diarrheal diseases worldwide. Research in the context of infection arising from transmission from other humans and other vertebrates has been extensive. A large fraction of these investigations has focused on domestic animals; however, there are also a number of publications which either totally, or at least in part, consider the role of wild or feral animals as carriers or spreaders of Campylobacter spp. Here, we carry out a systematic review to explore the role played by wild vertebrates as sources of Campylobacter spp. with a compilation of prevalence data for more than 150 species including reptiles, mammals and birds. We found that numerous vertebrate species can act as carriers of Campylobacter species, but we also found that some host specificity may exist, reducing the risk of spread from wildlife to domestic animals or humans.

Isolation and Genomic Characteristics of Cat-Borne Campylobacter felis sp. nov. and Sheep-Borne Campylobacter ovis sp. nov

Nine novel bacterial strains were isolated from the feces of cats and sheep in 2019 and 2020 in Beijing, China. Cells were 1-3 μm long and ≤0.5 μm wide, Gram-stain negative, microaerobic, motile, oxidase positive, and urease negative. Phylogenetic analyses based on 16S rRNA gene sequences indicated that these nine isolates belong to the genus Campylobacter but formed two robust clades that were clearly separate from the currently recognized species and, respectively, isolated from the cat and sheep. Both these strains shared low 16S rRNA gene sequence similarity, dDDH relatedness, and ANI values with their closest species C. upsaliensis CCUG 14913^T and C. lanienae NCTC 13004^T, and against each other, which are below the cut-off values generally recognized for isolates of the same species. The genomic DNA G + C contents of type strains XJK22-1^T and SYS25-1^T were 34.99 mol% and 32.43 mol%, respectively. Electron microscopy showed that these cells were spiral shaped, with bipolar single flagella. Based on results from genotypic, phenotypic, phylogenetic, and phylogenomic analyses, these nine strains represent two novel species within the genus Campylobacter, for which the names Campylobacter felis sp. nov. (Type strain XJK22-1^T = GDMCC 1.3684^T = JCM 35847^T) and Campylobacter ovis sp. nov. (Type strain SYS25-1^T = GDMCC 1.3685^T) are proposed.

Evolution and Role of Proteases in Campylobacter jejuni Lifestyle and Pathogenesis

Infection with the main human food-borne pathogen Campylobacter jejuni causes campylobacteriosis that accounts for a substantial percentage of gastrointestinal infections. The disease usually manifests as diarrhea that lasts for up to two weeks. C. jejuni possesses an array of peptidases and proteases that are critical for its lifestyle and pathogenesis. These include serine proteases Cj1365c, Cj0511 and HtrA; AAA+ group proteases ClpP, Lon and FtsH; and zinc-dependent protease PqqE, proline aminopeptidase PepP, oligopeptidase PepF and peptidase C26. Here, we review the numerous critical roles of these peptide bond-dissolving enzymes in cellular processes of C. jejuni that include protein quality control; protein transport across the inner and outer membranes into the periplasm, cell surface or extracellular space; acquisition of amino acids and biofilm formation and dispersal. In addition, we highlight their role as virulence factors that inflict intestinal tissue damage by promoting cell invasion and mediating cleavage of crucial host cell factors such as epithelial cell junction proteins. Furthermore, we reconstruct the evolution of these proteases in 34 species of the Campylobacter genus. Finally, we discuss to what extent C. jejuni proteases have initiated the search for inhibitor compounds as prospective novel anti-bacterial therapies.

Campylobacter bilis sp. nov., isolated from chickens with spotty liver disease

A novel species of Campylobacter was isolated from bile samples of chickens with spotty liver disease in Australia, making it the second novel species isolated from chickens with the disease, after Campylobacter hepaticus was isolated and described in 2016. Six independently derived isolates were obtained. They were Gram-stain-negative, microaerobic, catalase-positive, oxidase-positive and urease-negative. Unlike most other species of the genus Campylobacter, more than half of the tested strains of this novel species hydrolysed hippurate and most of them could not reduce nitrate. Distinct from C. hepaticus, many of the isolates were sensitive to 2,3,5-triphenyltetrazolium chloride (0.04%) and metronidazole (4 mg ml^-1), and all strains were sensitive to nalidixic acid. Phylogenetic analysis using 16S rRNA and hsp60 gene sequences demonstrated that the strains formed a robust clade that was clearly distinct from recognized Campylobacter species. Whole genome sequence analysis of the strains showed that the average nucleotide identity and the genome blast distance phylogeny values compared to other Campylobacter species were less than 86 and 66%, respectively, which are below the cut-off values generally recognized for isolates of the same species. The genome of the novel species has a DNA G+C content of 30.6 mol%, while that of C. hepaticus is 27.9 mol%. Electron microscopy showed that the cells were spiral-shaped, with bipolar unsheathed flagella. The protein spectra generated from matrix-assisted laser desorption/ionization time of flight analysis demonstrated that they are different from the most closely related Campylobacter species. These data indicate that the isolates belong to a novel Campylobacter species, for which the name Campylobacter bilis sp. nov. is proposed. The type strain is VicNov18^T (=ATCC TSD-231^T=NCTC 14611^T).

Campylobacter novaezeelandiae sp. nov., isolated from birds and water in New Zealand

Six isolates of Campylobacter with similar non-standard colonial morphologies were identified during studies isolating Campylobacter from bird faeces and rivers in New Zealand. Genomic (16S rRNA gene sequencing and whole genome analysis) and phenotypic (MALDI-TOF analysis and conventional biochemical tests) showed that the isolates form a monophyletic clade with genetic relationships to Campylobacter coli/Campylobacter jejuni and Campylobacter peloridis/Campylobacter amoricus. They may be distinguished from other Campylobacter by their MALDI-TOF spectral pattern, their florid α-haemolysis, their ability to grow anaerobically at 37 °C, and on 2 % NaCl nutrient agar, and their lack of hippuricase. This study shows that these isolates represent a novel species within the genus Campylobacter for which the name Campylobacter novaezeelandiae sp. nov. is proposed. The presence of C. novaezeelandiae in water may be a confounder for freshwater microbial risk assessment as they may not be pathogenic for humans. The type strain is B423bT (=NZRM 4741T=ATCC TSD-167T).

Campylobacter portucalensis sp. nov., a new species of Campylobacter isolated from the preputial mucosa of bulls

A new species of the Campylobacter genus is described, isolated from the preputial mucosa of bulls (Bos taurus). The five isolates obtained exhibit characteristics of Campylobacter, being Gram-negative non-motile straight rods, oxidase positive, catalase negative and microaerophilic. Phenotypic characteristics and nucleotide sequence analysis of 16S rRNA and hsp60 genes demonstrated that these isolates belong to a novel species within the genus Campylobacter. Based on hsp60 gene phylogenetic analysis, the most related species are C. ureolyticus, C. blaseri and C. corcagiensis. The whole genome sequence analysis of isolate FMV-PI01 revealed that the average nucleotide identity with other Campylobacter species was less than 75%, which is far below the cut-off for isolates of the same species. However, whole genome sequence analysis identified coding sequences highly homologous with other Campylobacter spp. These included several virulence factor coding genes related with host cell adhesion and invasion, transporters involved in resistance to antimicrobials, and a type IV secretion system (T4SS), containing virB2-virB11/virD4 genes, highly homologous to the C. fetus subsp. venerealis. The genomic G+C content of isolate FMV-PI01 was 28.3%, which is one of the lowest values reported for species of the genus Campylobacter. For this species the name Campylobacter portucalensis sp. nov. is proposed, with FMV-PI01 (= LMG 31504, = CCUG 73856) as the type strain.

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.

A review of the novel thermophilic Campylobacter, Campylobacter hepaticus, a pathogen of poultry

In 2015, a novel thermophilic Campylobacter was isolated from cases of spotty liver disease in laying hens in the UK. In 2016, it was isolated from laying hens in Australia where it was formally named Campylobacter hepaticus and confirmed as the cause of spotty liver disease. It has also been isolated from laying hens in America. It is fastidious, grows slowly on first isolation and does not grow on media used to routinely isolate Campylobacter. Spotty liver disease is an acute, randomly distributed, focal, necrotic hepatitis causing mortality in up to 10% of a flock and a 10%-15% fall in egg production. It occurs mainly in free-range hens or hens reared on the ground at around the time of peak lay. The incidence of the disease has increased in countries where there is an increase in keeping free-range laying hens. It is similar to the condition avian vibrionic hepatitis which was reported in America, Europe and Australasia in the 1950s to 1970s and the agent isolated from cases of avian vibrionic hepatitis and C. hepaticus appear to be very similar. It is not known if C. hepaticus is zoonotic but whole genome sequencing shows that it is most closely related to the known zoonotic campylobacters Campylobacter jejuni and Campylobacter coli. Human exposure to C. hepaticus is likely through similar exposure routes. Analysis of the whole genome showed a reduction in the genes for iron metabolism compared to C. jejuni. A requirement for iron was confirmed as it showed reduced growth in an iron depletion assay and this may explain its tissue tropism. With a move towards free-range egg production in many countries, the incidence of C. hepaticus hepatitis is likely to increase, but the identification of the causal agent will provide opportunities for the development of control methods.

Draft Whole-Genome Sequences of Three Isolates of a Novel Strain of a Campylobacter sp. Isolated from New Zealand Birds and Water

Campylobacter spp. are frequently found associated with the avian intestinal tract. Most are commensals, but some can cause human campylobacteriosis.

Campylobacter spp. are frequently found associated with the avian intestinal tract. Most are commensals, but some can cause human campylobacteriosis. Here, we report the draft genome sequences of three strains of a novel Campylobacter sp. isolated from urban birds and a rural river in New Zealand.

Characterization of Campylobacter spp. isolated from wild birds in the Antarctic and Sub-Antarctic

A lack of knowledge of naturally occurring pathogens is limiting our ability to use the Antarctic to study the impact human-mediated introduction of infectious microorganisms have on this relatively uncontaminated environment. As no large-scale coordinated effort to remedy this lack of knowledge has taken place, we rely on smaller targeted efforts to both study present microorganisms and monitor the environment for introductions. In one such effort, we isolated Campylobacter species from fecal samples collected from wild birds in the Antarctic Peninsula and the sub-Antarctic island of South Georgia. Indeed, in South Georgia, we found Campylobacter lari and the closely related Campylobacter peloridis, but also distantly related human-associated multilocus sequence types of Campylobacter jejuni. In contrast, in the Antarctic Peninsula, we found C. lari and two closely related species, Campylobacter subantarcticus and Campylobacter volucris, but no signs of human introduction. In fact, our finding of human-associated sequence types of C. jejuni in South Georgia, but not in the Antarctic Peninsula, suggests that efforts to limit the spread of infectious microorganisms to the Antarctic have so far been successful in preventing the introduction of C. jejuni. However, we do not know how it came to South Georgia and whether the same mode of introduction could spread it from there to the Antarctic Peninsula.

Campylobacter blaseri sp. nov., isolated from common seals (Phoca vitulina)

During a study to assess the faecal microbiome of common seals (Phoca vitulina) in a Dutch seal rehabilitation centre, 16S rRNA gene sequences of an unknown Campylobacter taxon were identified. Campylobacter isolates, which differed from the established Campylobacter taxa, were cultured and their taxonomic position was determined by a polyphasic study based on ten isolates. The isolates were characterized by 16S rRNA and atpA gene sequence analyses and by conventional phenotypic testing. Based on the whole genome sequences, the average nucleotide identity and core genome phylogeny were determined. The isolates formed a separate phylogenetic clade, divergent from all other Campylobacter taxa and most closely related to Campylobacter corcagiensis, Campylobacter geochelonis and Campylobacter ureolyticus. The isolates can be distinguished phenotypically from all other Campylobacter taxa based on their lack of motility, growth at 25 °C and growth on MacConkey agar. This study shows that these isolates represent a novel species within the genus Campylobacter, for which the name Campylobacter blaseri sp. nov. is proposed. The type strain for this novel species is 17S00004-5^T (=LMG 30333^T=CCUG 71276^T).

Minimal standards for describing new species belonging to the families Campylobacteraceae and Helicobacteraceae: Campylobacter, Arcobacter, Helicobacter and Wolinella spp

Ongoing changes in taxonomic methods, and in the rapid development of the taxonomic structure of species assigned to the Epsilonproteobacteria have lead the International Committee of Systematic Bacteriology Subcommittee on the Taxonomy of Campylobacter and Related Bacteria to discuss significant updates to previous minimal standards for describing new species of Campylobacteraceae and Helicobacteraceae. This paper is the result of these discussions and proposes minimum requirements for the description of new species belonging to the families Campylobacteraceae and Helicobacteraceae, thus including species in Campylobacter, Arcobacter, Helicobacter, and Wolinella. The core underlying principle remains the use of appropriate phenotypic and genotypic methods to characterise strains sufficiently so as to effectively and unambiguously determine their taxonomic position in these families, and provide adequate means by which the new taxon can be distinguished from extant species and subspecies. This polyphasic taxonomic approach demands the use of appropriate reference data for comparison to ensure the novelty of proposed new taxa, and the recommended study of at least five strains to enable species diversity to be assessed. Methodological approaches for phenotypic and genotypic (including whole-genome sequence comparisons) characterisation are recommended.

Inquiring into the Gaps of Campylobacter Surveillance Methods

Campylobacter is one of the most common pathogen-related causes of diarrheal illnesses globally and has been recognized as a significant factor of human disease for more than three decades. Molecular typing techniques and their combinations have allowed for species identification among members of the Campylobacter genus with good resolution, but the same tools usually fail to proceed to subtyping of closely related species due to high sequence similarity. This problem is exacerbated by the demanding conditions for isolation and detection from the human, animal or water samples as well as due to the difficulties during laboratory maintenance and long-term storage of the isolates. In an effort to define the ideal typing tool, we underline the strengths and limitations of the typing methodologies currently used to map the broad epidemiologic profile of campylobacteriosis in public health and outbreak investigations. The application of both the old and the new molecular typing tools is discussed and an indirect comparison is presented among the preferred techniques used in current research methodology.

Campylobacter pinnipediorum sp. nov., isolated from pinnipeds, comprising Campylobacter pinnipediorum subsp. pinnipediorum subsp. nov. and Campylobacter pinnipediorum subsp. caledonicus subsp. nov

During independent diagnostic screenings of otariid seals in California (USA) and phocid seals in Scotland (UK), Campylobacter-like isolates, which differed from the established taxa of the genus Campylobacter, were cultured from abscesses and internal organs of different seal species. A polyphasic study was undertaken to determine the taxonomic position of these six isolates. The isolates were characterized by 16S rRNA gene and AtpA sequence analysis and by conventional phenotypic testing. The whole-genome sequences were determined for all isolates, and the average nucleotide identity (ANI) was determined. The isolates formed a separate phylogenetic clade, divergent from all other taxa of the genus Campylobacter and most closely related to Campylobactermucosalis. Although all isolates showed 100 % 16S rRNA gene sequence homology, AtpA and ANI analyses indicated divergence between the otariid isolates from California and the phocid isolates from Scotland, which warrants subspecies status for each clade. The two subspecies could also be distinguished phenotypically on the basis of catalase activity. This study shows clearly that the isolates obtained from pinnipeds represent a novel species within the genus Campylobacter, for which the name Campylobacter pinnipediorum sp. nov. is proposed. Within this novel species, the Californian isolates represent a separate subspecies, for which the name C. pinnipediorum subsp. pinnipediorum subsp. nov. is proposed. The type strain for both this novel species and subspecies is RM17260T (=LMG 29472T=CCUG 69570T). The Scottish isolates represent another subspecies, for which the name C. pinnipediorum subsp. caledonicus subsp. nov. is proposed. The type strain of this subspecies is M302/10/6T (=LMG 29473T=CCUG 68650T).

Towards understanding clinical campylobacter infection and its transmission: time for a different approach?

Campylobacter spp. are among the most commonly diagnosed causes of human infection. Methods for detection of the 29 campylobacter species have mainly focused on cultivation of the thermophilic species. More than 99% of clinical campylobacter isolates notified in the UK in the recent past have been from faecal samples and associated with gastroenteritis. Campylobacter enteritis notifications in temperate zones show a seasonal increase during the summer months with a sharp decrease in the winter months, a pattern which remains incompletely understood. The striking seasonality in the expression of many human genes, some concerned with inflammation and immunity, suggests a need for further study of the host regarding the temporal distribution of many human infections, including campylobacteriosis. A tendency for campylobacter to enter a non-cultivable state under adverse conditions effects a reduction in the number of isolations. A Polymerase Chain Reaction (PCR)-based screening approach for the presence of the Campylobacter genus and followed by speciation has provided some insight into the limitations of cultivation for campylobacter, also allowing the discovery of new species. The increased sensitivity of the PCR-based approach over culture-based methods may make it difficult for the laboratory to differentiate asymptomatic campylobacter carriage from clinical campylobacter infection in non-sterile body sites. Campylobacter infection depends on a combination of host factors, and on acquisition of a suitably virulent strain with a tropism for human epithelium. The possibility of persistence of campylobacter in a viable but non-culturable latent form in the human body may also require further investigation. The scope of this review includes a discussion of current methods for diagnosing acute campylobacter infection and for detecting campylobacter in water and foodstuffs. The review also questions the prevailing view that poultry is the most common source of campylobacteriosis.

Comparative genomics of the Campylobacter lari group

The Campylobacter lari group is a phylogenetic clade within the epsilon subdivision of the Proteobacteria and is part of the thermotolerant Campylobacter spp., a division within the genus that includes the human pathogen Campylobacter jejuni. The C. lari group is currently composed of five species (C. lari, Campylobacter insulaenigrae, Campylobacter volucris, Campylobacter subantarcticus, and Campylobacter peloridis), as well as a group of strains termed the urease-positive thermophilic Campylobacter (UPTC) and other C. lari-like strains. Here we present the complete genome sequences of 11 C. lari group strains, including the five C. lari group species, four UPTC strains, and a lari-like strain isolated in this study. The genome of C. lari subsp. lari strain RM2100 was described previously. Analysis of the C. lari group genomes indicates that this group is highly related at the genome level. Furthermore, these genomes are strongly syntenic with minor rearrangements occurring only in 4 of the 12 genomes studied. The C. lari group can be bifurcated, based on the flagella and flagellar modification genes. Genomic analysis of the UPTC strains indicated that these organisms are variable but highly similar, closely related to but distinct from C. lari. Additionally, the C. lari group contains multiple genes encoding hemagglutination domain proteins, which are either contingency genes or linked to conserved contingency genes. Many of the features identified in strain RM2100, such as major deficiencies in amino acid biosynthesis and energy metabolism, are conserved across all 12 genomes, suggesting that these common features may play a role in the association of the C. lari group with coastal environments and watersheds.

Biological roles of the O-methyl phosphoramidate capsule modification in Campylobacter jejuni

Campylobacter jejuni is a major cause of bacterial gastroenteritis worldwide, and the capsular polysaccharide (CPS) of this organism is required for persistence and disease. C. jejuni produces over 47 different capsular structures, including a unique O-methyl phosphoramidate (MeOPN) modification present on most C. jejuni isolates. Although the MeOPN structure is rare in nature it has structural similarity to some synthetic pesticides. In this study, we have demonstrated, by whole genome comparisons and high resolution magic angle spinning NMR, that MeOPN modifications are common to several Campylobacter species. Using MeOPN biosynthesis and transferase mutants generated in C. jejuni strain 81-176, we observed that loss of MeOPN from the cell surface correlated with increased invasion of Caco-2 epithelial cells and reduced resistance to killing by human serum. In C. jejuni, the observed serum mediated killing was determined to result primarily from activation of the classical complement pathway. The C. jejuni MeOPN transferase mutant showed similar levels of colonization relative to the wild-type in chickens, but showed a five-fold drop in colonization when co-infected with the wild-type in piglets. In Galleria mellonella waxmoth larvae, the MeOPN transferase mutant was able to kill the insects at wild-type levels. Furthermore, injection of the larvae with MeOPN-linked monosaccharides or CPS purified from the wild-type strain did not result in larval killing, indicating that MeOPN does not have inherent insecticidal activity.

Diversity in the protein N-glycosylation pathways within the Campylobacter genus

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

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.

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

This study used an adapted cultural protocol for the recovery of fastidious species of Campylobacter, to gain a more accurate understanding of the diversity of Campylobacter populations in fresh meats. Chicken (n=185), pork (n=179) and beef (n=186) were collected from supermarkets and butchers throughout the Republic of Ireland. Samples were enriched in Campylobacter enrichment broth for 24h under an atmosphere of 2.5% O(2), 7% H(2), 10% CO(2), and 80.5% N(2). The enriched samples were then filtered onto non-selective Anaerobe Basal Agar supplemented with lysed horse blood using mixed ester filter membranes. Isolates were identified by both genus and species-specific PCR assays and biochemical testing. The incidence of campylobacters on beef (36%) was significantly higher than on pork (22%) or chicken (16%), and far exceeds previously reported prevalence levels. The method was successful in recovering 7 species of Campylobacter, including the fastidious spp. C. concisus and C. mucosalis, from chicken meat, and 10 species, including C. concisus, C. curvus, C. mucosalis, C. sputorum, and C. upsaliensis, from minced beef. The isolation of C. concisus and C. upsaliensis from meat in this study is of particular significance, due to their emerging clinical relevance. The results of this study confirm that the diversity of Campylobacter species on fresh meats is greater than previously reported and highlights the bias of cultural methods towards the recovery of C. jejuni.

Campylobacter volucris sp. nov., isolated from black-headed gulls (Larus ridibundus)

During a study of the prevalence of Campylobacter jejuni in black-headed gulls (Larus ridibundus) in Sweden, three isolates, strains LMG 24379, LMG 24380T and LMG 24381, were initially identified as Campylobacter lari. Further characterization by both AFLP and whole-cell protein SDS-PAGE analyses revealed that they formed a distinct group in the genus Campylobacter. This unique position was confirmed by phenotypic characterization, 16S rRNA and hsp60 gene sequence analysis and DNA-DNA hybridizations. The combined data confirm that these isolates represent a novel species within the genus Campylobacter, for which the name Campylobacter volucris sp. nov. is proposed. The type strain is LMG 24380T (=CCUG 57498T).