Review

Authors: Alexandra Tikhomirova, Emmylee R McNabb, Luca Petterlin...

Campylobacter jejuni is a very common cause of gastroenteritis, and is frequently transmitted to humans through contaminated food products or water. Importantly, C. jejuni infections have a range of short- and long-term sequelae such as irritable bowel syndrome and Guillain Barre syndrome. C. jejuni triggers disease by employing a range of molecular strategies which enable it to colonise the gut, invade the epithelium, persist intracellularly and avoid detection by the host immune response. The objective of this review is to explore and summarise recent advances in the understanding of the C. jejuni molecular factors involved in colonisation, invasion of cells, collective quorum sensing-mediated behaviours and persistence. Understanding the mechanisms that underpin the pathogenicity of C. jejuni will enable future development of effective preventative approaches and vaccines against this pathogen.

Topics: Campylobacter jejuni; Virulence Factors; Humans; Campylobacter Infections; Quorum Sensing

PubMed: 38693534
DOI: 10.1186/s12929-024-01033-6

Review

Authors: Samuel K Sheppard, Martin C J Maiden

The global significance of Campylobacter jejuni and Campylobacter coli as gastrointestinal human pathogens has motivated numerous studies to characterize their population biology and evolution. These bacteria are a common component of the intestinal microbiota of numerous bird and mammal species and cause disease in humans, typically via consumption of contaminated meat products, especially poultry meat. Sequence-based molecular typing methods, such as multilocus sequence typing (MLST) and whole genome sequencing (WGS), have been instructive for understanding the epidemiology and evolution of these bacteria and how phenotypic variation relates to the high degree of genetic structuring in C. coli and C. jejuni populations. Here, we describe aspects of the relatively short history of coevolution between humans and pathogenic Campylobacter, by reviewing research investigating how mutation and lateral or horizontal gene transfer (LGT or HGT, respectively) interact to create the observed population structure. These genetic changes occur in a complex fitness landscape with divergent ecologies, including multiple host species, which can lead to rapid adaptation, for example, through frame-shift mutations that alter gene expression or the acquisition of novel genetic elements by HGT. Recombination is a particularly strong evolutionary force in Campylobacter, leading to the emergence of new lineages and even large-scale genome-wide interspecies introgression between C. jejuni and C. coli. The increasing availability of large genome datasets is enhancing understanding of Campylobacter evolution through the application of methods, such as genome-wide association studies, but MLST-derived clonal complex designations remain a useful method for describing population structure.

Topics: Adaptation, Physiological; Campylobacter coli; Campylobacter jejuni; Evolution, Molecular; Recombination, Genetic

PubMed: 26101080
DOI: 10.1101/cshperspect.a018119

Review

Authors: Kshipra Chandrashekhar, Issmat I Kassem, Gireesh Rajashekara...

Chemotaxis, a process that mediates directional motility toward or away from chemical stimuli (chemoeffectors/ligands that can be attractants or repellents) in the environment, plays an important role in the adaptation of Campylobacter jejuni to disparate niches. The chemotaxis system consists of core signal transduction proteins and methyl-accepting-domain-containing Transducer like proteins (Tlps). Ligands binding to Tlps relay a signal to chemotaxis proteins in the cytoplasm which initiate a signal transduction cascade, culminating into a directional flagellar movement. Tlps facilitate substrate-specific chemotaxis in C. jejuni, which plays an important role in the pathogen's adaptation, pathobiology and colonization of the chicken gastrointestinal tract. However, the role of Tlps in C. jejuni's host tissue specific colonization, physiology and virulence remains not completely understood. Based on recent studies, it can be predicted that Tlps might be important targets for developing strategies to control C. jejuni via vaccines and antimicrobials.

Topics: Animals; Bacterial Proteins; Campylobacter Infections; Campylobacter jejuni; Chemotaxis; Chickens; Gastrointestinal Tract

PubMed: 28080213
DOI: 10.1080/19490976.2017.1279380

Review

Authors: Zahra Omole, Nick Dorrell, Abdi Elmi...

is the leading cause of bacterial gastroenteritis and is a major public health concern worldwide. Despite its importance, our understanding of how causes diarrhoea and interacts with its hosts is limited due to the absence of appropriate infection models and established virulence factors found in other enteric pathogens. Additionally, despite its genetic diversity, non-pathogenic strains are unknown. Regardless of these limitations, significant progress has been made in understanding how uses a complex array of factors which aid the bacterium to survive and respond to host defences. This review provides an update on fitness and virulence determinants of this important pathogen and questions our knowledge on these determinants that are often based on inferred genomics knowledge and surrogate infection models.

Topics: Campylobacter jejuni; Campylobacter Infections; Virulence; Humans; Virulence Factors; Animals; Gastroenteritis

PubMed: 39648291
DOI: 10.1080/21505594.2024.2436060

Authors: Pablo Fernández-Palacios, Fátima Galán-Sánchez, Carlos S Casimiro-Soriguer...

is the main cause of bacterial gastroenteritis and a public health problem worldwide. Little information is available on the genotypic characteristics of human in Spain. This study is based on an analysis of the resistome, virulome, and phylogenetic relationship, antibiogram prediction, and antimicrobial susceptibility of 114 human isolates of from a tertiary hospital in southern Spain from October 2020 to June 2023. The isolates were sequenced using Illumina technology, and a bioinformatic analysis was subsequently performed. The susceptibility of isolates to ciprofloxacin, tetracycline, and erythromycin was also tested. The resistance rates for each antibiotic were 90.3% for ciprofloxacin, 66.7% for tetracycline, and 0.88% for erythromycin. The fluoroquinolone resistance rate obtained is well above the European average (69.1%). CC-21 ( = 23), ST-572 ( = 13), and ST-6532 ( = 13) were the most prevalent clonal complexes (CCs) and sequence types (STs). In the virulome, the , and genes were detected in all the isolates. A prevalence of 20.1% was obtained for the genes and , which are related to the pathogenesis of Guillain-Barré syndrome (GBS). The prevalence of the main antimicrobial resistance markers detected were CmeABC (92.1%), RE-cmeABC (7.9%), the T86I substitution in (88.9%), (72.6%) (65.8%), and (17.1%). High antibiogram prediction rates (>97%) were obtained, except for in the case of the erythromycin-resistant phenotype. This study contributes significantly to the knowledge of genomics for the prevention, treatment, and control of infections caused by this pathogen.IMPORTANCEDespite being the pathogen with the greatest number of gastroenteritis cases worldwide, remains a poorly studied microorganism. A sustained increase in fluoroquinolone resistance in human isolates is a problem when treating infections. The development of whole genome sequencing (WGS) techniques has allowed us to better understand the genotypic characteristics of this pathogen and relate them to antibiotic resistance phenotypes. These techniques complement the data obtained from the phenotypic analysis of isolates. The zoonotic transmission of through the consumption of contaminated poultry supports approaching the study of this pathogen through "One Health" approach. In addition, due to the limited information on the genomic characteristics of in Spain, this study provides important data and allows us to compare the results with those obtained in other countries.

Topics: Campylobacter jejuni; Humans; Spain; Anti-Bacterial Agents; Campylobacter Infections; Microbial Sensitivity Tests; Genotype; Phylogeny; Adult; Drug Resistance, Bacterial; Male; Female; Middle Aged; Aged; Child; Adolescent; Young Adult; Ciprofloxacin; Erythromycin; Child, Preschool; Tetracycline; Infant; Aged, 80 and over

PubMed: 39162511
DOI: 10.1128/spectrum.01028-24

Review

Authors: Jerica Sabotič, Nika Janež, Manca Volk...

Microaerophilic, Gram-negative Campylobacter jejuni is the causative agent of campylobacteriosis, the most common bacterial gastrointestinal infection worldwide. Adhesion is the crucial first step in both infection or interaction with the host and biofilm formation, and is a critical factor for bacterial persistence. Here we describe the proteins and other surface structures that promote adhesion to various surfaces, including abiotic surfaces, microorganisms, and animal and human hosts. In addition, we provide insight into the distribution of adhesion proteins among strains from different ecological niches and highlight unexplored proteins involved in C. jejuni adhesion. Protein-protein, protein-glycan, and glycan-glycan interactions are involved in C. jejuni adhesion, with different factors contributing to adhesion to varying degrees under different circumstances. As adhesion is essential for survival and persistence, it represents an interesting target for C. jejuni control. Knowledge of the adhesion process is incomplete, as different molecular and functional aspects have been studied for different structures involved in adhesion. Therefore, it is important to strive for an integration of different approaches to obtain a clearer picture of the adhesion process on different surfaces and to consider the involvement of proteins, glycoconjugates, and polysaccharides and their cooperation.

Topics: Humans; Animals; Bacterial Adhesion; Campylobacter jejuni; Molecular Structure; Polysaccharides; Campylobacter Infections

PubMed: 38029692
DOI: 10.1016/j.vetmic.2023.109918

Authors: Ana Beatriz Garcez Buiatte, Stephanie S R Souza, Leticia Roberta Martins Costa...

Consumption of raw, undercooked or contaminated animal food products is a frequent cause of infection. Brazil is the world's third largest producer and a major exporter of chicken meat, yet population-level genomic investigations of in the country remain scarce. Analysis of 221 . genomes from Brazil shows that the overall core and accessory genomic features of are influenced by the identity of the human or animal source. Of the 60 sequence types detected, ST353 is the most prevalent and consists of samples from chicken and human sources. Notably, we identified the presence of diverse genes from the OXA-61 and OXA-184 families that confer beta-lactam resistance as well as the operon related to multidrug efflux pump, which contributes to resistance against tetracyclines, macrolides and quinolones. Based on limited data, we estimated the most recent common ancestor of ST353 to the late 1500s, coinciding with the time the Portuguese first arrived in Brazil and introduced domesticated chickens into the country. We identified at least two instances of ancestral chicken-to-human infections in ST353. The evolution of in Brazil was driven by the confluence of clinically relevant genetic elements, multi-host adaptation and clonal population growth that coincided with major socio-economic changes in poultry farming.

Topics: Campylobacter jejuni; Brazil; Animals; Chickens; Humans; Genome, Bacterial; Evolution, Molecular; Campylobacter Infections; Host Adaptation; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Phylogeny

PubMed: 39028633
DOI: 10.1099/mgen.0.001274

Authors: Luyao Ma, Michael E Konkel, Xiaonan Lu...

Horizontal gene transfer (HGT) is a driving force for the dissemination of antimicrobial resistance (AMR) genes among Campylobacter jejuni organisms, a leading cause of foodborne gastroenteritis worldwide. Although HGT is well documented for C. jejuni planktonic cells, the role of C. jejuni biofilms in AMR spread that likely occurs in the environment is poorly understood. Here, we developed a cocultivation model to investigate the HGT of chromosomally encoded AMR genes between two C. jejuni F38011 AMR mutants in biofilms. Compared to planktonic cells, C. jejuni biofilms significantly promoted HGT (0.05), resulting in an increase of HGT frequencies by up to 17.5-fold. Dynamic study revealed that HGT in biofilms increased at the early stage (i.e., from 24 h to 48 h) and remained stable during 48 to 72 h. Biofilms continuously released the HGT mutants into supernatant culture, indicating spontaneous dissemination of AMR to broader niches. DNase I treatment confirmed the role of natural transformation in genetic exchange. HGT was not associated with biofilm biomass, cell density, or bacterial metabolic activity, whereas the presence of extracellular DNA was negatively correlated with the altered HGT frequencies. HGT in biofilms also had a strain-to-strain variation. A synergistic HGT effect was observed between C. jejuni with different genomic backgrounds (i.e., C. jejuni NCTC 11168 chloramphenicol-resistant strain and F38011 kanamycin-resistant strain). C. jejuni performed HGT at the frequency of 10 in Escherichia coli-C. jejuni biofilms, while HGT was not detectable in Salmonella entericaC. jejuni biofilms. Antimicrobial-resistant C. jejuni has been listed as a high priority of public health concern worldwide. To tackle the rapid evolution of AMR in C. jejuni, it is of great importance to understand the extent and characteristics of HGT in C. jejuni biofilms, which serve as the main survival strategy of this microbe in the farm-to-table continuum. In this study, we demonstrated that biofilms significantly enhanced HGT compared to the planktonic state (0.05). Biofilm cultivation time and extracellular DNA (eDNA) amount were related to varied HGT frequencies. C. jejuni could spread AMR genes in both monospecies and dual-species biofilms, mimicking the survival mode of C. jejuni in food chains. These findings indicated that the risk and extent of AMR transmission among C. jejuni organisms have been underestimated, as previous HGT studies mainly focused on the planktonic state. Future AMR controlling measures can target biofilms and their main component eDNA.

Topics: Biofilms; Campylobacter jejuni; DNA, Bacterial; Drug Resistance, Bacterial; Gene Transfer, Horizontal

PubMed: 33990313
DOI: 10.1128/AEM.00659-21

Authors: Harald Nothaft, Xin Liu, Jianjun Li...

The Campylobacter jejuni N-linked protein glycosylation pathway produces a heptasaccharide that is added to >65 periplasmic and membrane proteins and is also released into the periplasm as the free oligosaccharide (fOS). The fOS is a novel soluble component of the C. jejuni periplasmic space that exists in 10-fold greater quantities than its asparagine-linked counterpart. Structurally, fOS is the same heptasaccharide that is found attached to asparagine residues on C. jejuni glycoproteins and both glycans are cleaved from the undecaprenylpyrophosphate anchor by the previously identified oligosaccharyltransferase PglB, which we have now shown to be a bifunctional enzyme also displaying hydrolase activity. The fOS levels in C. jejuni, similar to bacterial periplasmic glucans, can be manipulated by altering the salt and osmolyte concentrations in the growth environment. Here, we outline potential functions of fOS and raise new questions about the underlying mechanism involved in PglB-mediated fOS release from its lipid anchor and fOS retention within the C. jejuni periplasm.

Topics: Acetyltransferases; Asparagine; Bacterial Proteins; Campylobacter jejuni; Glycosylation; Hexosyltransferases; Membrane Proteins; Oligosaccharides; Periplasmic Proteins; Polysaccharides, Bacterial

PubMed: 21178500
DOI: 10.4161/viru.1.6.13801

Review

Authors: Abofu Alemka, Nicolae Corcionivoschi, Billy Bourke...

Mucus colonization is an essential early step toward establishing successful infection and disease by mucosal pathogens. There is an emerging literature implicating specific mucin sub-types and mucin modifications in protecting the host from Campylobacter jejuni infection. However, mucosal pathogens have evolved sophisticated mechanisms to breach the mucus layer and C. jejuni in particular appears to harbor specific adaptations to better colonize intestinal mucus. For example, components of mucus are chemotactic for C. jejuni and the rheological properties of mucus promote motility of the organism. Furthermore, recent studies demonstrate that mucins modulate the pathogenicity of C. jejuni in a species-specific manner and likely help determine whether these bacteria become pathogenic (as in humans), or adopt a commensal mode of existence (as in chickens and other animals). This review focuses on recent advances in understanding the complex interplay between C. jejuni and components of the mucus layer.

Topics: Animals; Campylobacter jejuni; Host-Pathogen Interactions; Humans; Intestinal Mucosa; Mucus

PubMed: 22919607
DOI: 10.3389/fcimb.2012.00015