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Background. Campylobacter species cause a high proportion of bacterial gastroenteritis cases and are a significant burden on health care systems and economies worldwide; however, the relative contributions of the various possible sources of infection in humans are unclear. Methods. National-scale genotyping of Campylobacter species was used to quantify the relative importance of various possible sources of human infection. Multilocus sequence types were determined for 5674 isolates obtained from cases of human campylobacteriosis in Scotland from July 2005 through September 2006 and from 999 Campylobacter species isolates from 3417 contemporaneous samples from potential human infection sources. These data were supplemented with 2420 sequence types from other studies, representing isolates from a variety of sources. The clinical isolates were attributed to possible sources on the basis of their sequence types with use of 2 population genetic models, STRUCTURE and an asymmetric island model. Results. The STRUCTURE and the asymmetric island models attributed most clinical isolates to chicken meat (58% and 78% of Campylobacter jejuni and 40% and 56% of Campylobacter coli isolates, respectively), identifying it as the principal source of Campylobacter infection in humans. Both models attributed the majority of the remaining isolates to ruminant sources, with relatively few isolates attributed to wild bird, environment, swine, and turkey sources. Conclusions. National-scale genotyping was a practical and efficient methodology for the quantification of the contributions of different sources to human Campylobacter infection. Combined with the knowledge that retail chicken is routinely contaminated with Campylobacter, these results are consistent with the view that the largest reductions in human campylobacteriosis in industrialized countries will come from interventions that focus on the poultry industry.

Campylobacter spp. are leading bacterial gastroenteritis pathogens. Infections are largely underreported, and the burden of outbreaks may be underestimated. Current strategies of testing as few as one isolate per sample can affect attribution of cases to epidemiologically important sources with high Campylobacter diversity, such as chicken meat. Multiple culture method combinations were utilized to recover and sequence Campylobacter from 45 retail chicken samples purchased across Norwich, UK, selecting up to 48 isolates per sample. Simulations based on resampling were used to assess the impact of Campylobacter sequence type (ST) diversity on outbreak detection. Campylobacter was recovered from 39 samples (87%), although only one sample was positive through all broth, temperature, and plate combinations. Three species were identified (Campylobacter jejuni, Campylobacter coli, and Campylobacter lari), and 33% of samples contained two species. Positive samples contained 1–8 STs. Simulation revealed that up to 87 isolates per sample would be required to detect 95% of the observed ST diversity, and 26 isolates would be required for the average probability of detecting a random theoretical outbreak ST to reach 95%. An optimized culture approach and selecting multiple isolates per sample are essential for more complete Campylobacter recovery to support outbreak investigation and source attribution.

The increasing availability of hundreds of whole bacterial genomes provides opportunities for enhanced understanding of the genes and alleles responsible for clinically important phenotypes and how they evolved. However, it is a significant challenge to develop easy-to-use and scalable methods for characterizing these large and complex data and relating it to disease epidemiology. Existing approaches typically focus on either homologous sequence variation in genes that are shared by all isolates, or non-homologous sequence variation--focusing on genes that are differentially present in the population. Here we present a comparative genomics approach that simultaneously approximates core and accessory genome variation in pathogen populations and apply it to pathogenic species in the genus Campylobacter. A total of 7 published Campylobacter jejuni and Campylobacter coli genomes were selected to represent diversity across these species, and a list of all loci that were present at least once was compiled. After filtering duplicates a 7-isolate reference pan-genome, of 3,933 loci, was defined. A core genome of 1,035 genes was ubiquitous in the sample accounting for 59% of the genes in each isolate (average genome size of 1.68 Mb). The accessory genome contained 2,792 genes. A Campylobacter population sample of 192 genomes was screened for the presence of reference pan-genome loci with gene presence defined as a BLAST match of ≥ 70% identity over ≥ 50% of the locus length--aligned using MUSCLE on a gene-by-gene basis. A total of 21 genes were present only in C. coli and 27 only in C. jejuni, providing information about functional differences associated with species and novel epidemiological markers for population genomic analyses. Homologs of these genes were found in several of the genomes used to define the pan-genome and, therefore, would not have been identified using a single reference strain approach.

Background Freshwater is a major source of human waterborne infections caused by Campylobacter species. The extensive use of antibiotics is capable of causing the emergence and spread of Campylobacter strains that are resistant to the antibiotics, making campylobacteriosis more difficult to treat and persistent in the environment. This study evaluated the occurrence and antimicrobial resistance profiles of Campylobacter species in freshwater from the Eastern Cape Province, South Africa. Materials and methods Sixty-one freshwater samples were collected, yielding 302 presumptive Campylobacter isolates. PCR assays confirmed 78 isolates as belonging to Campylobacter species, identifying 35 (45%) as C. jejuni , 29 (37%) as C. coli , and 14 (18%) as C. lari . Antibiotic susceptibility testing was conducted to determine resistance patterns. Results The isolates showed high resistance to erythromycin (90%) and low resistance to gentamicin (11.58%). The most frequently observed resistance pattern was C-LEV-NA-AZM-CIP-AMP-IMI-GM-DO-S-TE-E for C. lari , C-LEV-NA-AZM-CIP-AMP-GM-DO-S-TE-E for C. jejuni , and C-LEV-NA-AZM-CIP-AMPI-GM-DO-TE-E for C. coli. (Chloramphenicol, Levofloxacin, Nalidixic acid, Azithromycin, Ciprofloxacin, Ampicillin, Imipenem, Gentamicin, Doxycycline, Streptomycin, Tetracycline, and Erythromycin). Most isolates had multiple antibiotic resistance (MAR) indices greater than 0.2. Genetic analysis revealed imipenem resistance genes ( bla IMP ) in 85.71% of isolates, followed by bla VIM (71.43%). The ermA gene was detected in only 4% of cases. The isolates tested negative for bla KPC , bla GES , ermC , and qnrA resistance genes. Conclusion The study shows that antimicrobial-resistant and potentially virulent Campylobacter strains are present in the freshwater environments in the Eastern Cape Province, posing a potential public health risk. However, surveillance systems and public awareness about campylobacteriosis and its transmission routes can reduce infection rates.

Campylobacter is gram-negative bacteria considered the predominant genera isolated from poultry samples and associated with gastroenteritis. Due to the problems in conventional cultural methods of time-consuming and technically demanding requirements, a rapid and feasible method for their identification and discrimination of the closely related spp. Including Campylobacter coli , Campylobacter fetus , and Campylobacter jejuni is needed. This study analyzes the chicken and sheep meats samples ( n  = 125) using culture and pre-enrichment-based Quadraplex real-time PCR by targeting OrfA, CstA , HipO , and 16 S rRNA genes of C. coli , C. fetus , C. jejuni and Campylobacter spp. Respectively. The analysis of 125 chicken and sheep meat samples by culture and real-time PCR showed high concordance between the results of the two methods. The present study show high prevalence of Campylobacter species (35% and 32% from chicken and meat respectively) of which C. jejuni were the most abundant. Reaction efficiencies were between 90 and 110%, and detect as low as 8.9 fg in C. jejuni . The need for quick detection and discrimination methods in sheep and chicken meat can be met using the described Quadraplex real-time PCR methodology.

A biofilm is a complex microbial community that protects bacterial cells from various stressors, including harsh environmental conditions, antimicrobial treatments, and host immune responses. This protective capability enhances Campylobacter survival during food processing and storage and facilitates transmission to humans. Despite their importance, the molecular mechanisms underlying Campylobacter biofilm formation and its impact on pathogen persistence remain poorly understood. In this study, we characterized the biofilm-forming ability of 18 C. jejuni and C. coli strains isolated from retail meat and performed whole-genome sequencing and comparative genomic analysis to identify strain-specific genes contributing to biofilm formation and maintenance. Phenotypic analysis revealed that C. jejuni strains YH001 and YH027 exhibited the strongest biofilm-forming capacity, producing the highest biomass among all isolates. Phylogenetic analysis indicated a close genetic relationship between these two strains, while pangenome analysis identified 19 unique genes/proteins specific to these strains. Functional annotation indicated their critical roles in adhesion, extracellular matrix production, and stress response. These findings demonstrate strain-specific biofilm formation in Campylobacter and highlight genetic determinants that may serve as targets for novel therapeutic approaches and intervention strategies to disrupt biofilms, improve food safety, and reduce persistent infections.

Campylobacter is the leading cause of bacterial gastroenteritis worldwide and an emerging and neglected pathogen in South America. This zoonotic pathogen colonizes the gastrointestinal tract of a wide range of mammals and birds, with poultry as the most important reservoir for human infections. Apart from its high morbidity rates, the emergence of resistant strains is of global concern. The aims of this work were to determine genetic diversity, presence of antimicrobial resistance determinants and virulence potential of Campylobacter spp. isolated from patients with acute gastrointestinal disease at ‘Clinica Alemana’, Santiago de Chile. The study considered the isolation of Campylobacter spp., from stool samples during a 20-month period (January 2020 to September 2021). We sequenced (NextSeq, Illumina) and performed an in-depth analysis of the genome sequences of 88 Campylobacter jejuni and 2 Campylobacter coli strains isolated from clinical samples in Chile. We identified a high genetic diversity among C. je juni strains and the emergence of prevalent clonal complexes, which were not identified in our previous reports. While ~40% of strains harbored a mutation in the gyrA gene associated with fluoroquinolone resistance, no macrolide-resistance determinants were detected. Interestingly, gene clusters encoding virulence factors such as the T6SS or genes associated with long-term sequelae such as Guillain-Barré syndrome showed lineage-relatedness. In addition, our analysis revealed a high degree of variability regarding the presence of fT3SS and T6SS effector proteins in comparison to type strains 81-176, F38011, and NCTC 11168 and 488. Our study provides important insights into the molecular epidemiology of this emerging foodborne pathogen. In addition, the differences observed regarding the repertoire of fT3SS and T6SS effector proteins could have an impact on the pathogenic potential and transmissibility of these Latin American isolates, posing another challenge in characterizing the infection dynamics of this emergent and neglected bacterial pathogen.

Campylobacter spp., primarily C. jejuni and C. coli , are leading causes of bacterial gastroenteritis worldwide. This review provides an overview of literature on the prevalence and distribution of virulence genes in C. jejuni and C. coli isolated from both food samples and humans across GCC countries. The reviewed evidence highlights a gap in our understanding of how differences in the virulence profile affect the pathogenicity of Campylobacter . Research has shown that C. coli is the predominant species found in retail chicken carcasses in the UAE, while C. jejuni is more common in chicken carcasses across other GCC countries. Studies also reveal distinct genotypes of C. jejuni and C. coli , each with varying pathogenicity. These findings underscore the need for further research on the role of virulence genes in shaping the pathogenicity of Campylobacter, which is essential for developing effective intervention and control strategies in the GCC region.

Gastrointestinal disease is one of the most common reasons for hospitalization in non-human primate colonies and accounts for over one-third of non-research related euthanasia. In rhesus macaques, this manifests as both acute diarrhea and chronic enterocolitis (CE), a syndrome of chronic diarrhea resulting in poor weight gain or weight loss which is minimally responsive to treatment. Campylobacter spp. are major causes of acute enterocolitis in rhesus macaques and may predispose individuals to the development of CE, similar to post-infectious irritable bowel syndrome in humans. Despite these concerns, there are few studies characterizing Campylobacter in rhesus macaque colonies, in particular utilizing whole genome sequencing and assessing findings with respect to the health status of the host. Our findings provide insight into Campylobacter strains circulating in rhesus macaque colonies, which can improve clinical monitoring, assist in treatment decisions, and provide new avenues of investigation into campylobacteriosis as a catalyst for CE.

Background Thermophilic Campylobacter species cause significant economic losses in cases of enteritis in poultry. Objective The aim of this study was to isolate and identify Campylobacter jejuni, Campylobacter coli and Campylobacter lari from chicken and turkey faeces samples using bacteriological and molecular methods. Also, to determine the antibiotic susceptibilities and antibiotic resistance genes of the isolates. Materials and Methods Within the scope of the study, 201 cloacal swab samples were collected from 132 chickens and 69 turkeys. Phenotypic and genotypic examinations were performed on the isolates obtained for resistance to various antimicrobial agents. Results Campylobacter spp. was isolated from 38.30% of the samples. PCR (polymerase chain reaction) analysis identified 63.63% of the isolates as C. jejuni and 23.37% as C. coli. The highest resistance rates of the isolates were determined against cephalothin (81.81%), nalidixic acid (72.72%) and aztreonam (61.03%). Multidrug resistance was found in 50% of Campylobacter spp. strains. The highest susceptibility in C. jejuni and C. coli strains was observed against gentamicin (95.91% and 100%). Statistical analyses demonstrated no significant differences between C. jejuni and C. coli with respect to most of the antibiotics tested (p > 0.05). However, a statistically significant difference was observed for nalidixic acid (p = 0.009). The blaOXA‐61 gene tested positive in 79.71% of the phenotypically ampicillin‐resistant isolates. The tet(O) gene was identified in 72.2% of tetracycline‐resistant isolates and the aphA‐3‐1 gene in 5.8% of aminoglycoside‐resistant isolates. The ERY2074 and ERY2075 genes were identified in 50% and 78.57% of the 28 isolates with erythromycin resistance genes, respectively. The cmeA, cmeB and cmeC genes were identified in 51.28%, 79.48% and 25.6% of the strains that developed multidrug resistance, respectively. The Thr‐86‐Ile point mutation was found in 92% of the isolates that carried the gyrA gene responsible for quinolone resistance. Conclusion The high susceptibility of the isolates to gentamicin in vitro suggests that gentamicin could be a potential agent for limiting Campylobacter colonization in poultry. High rates of multidrug resistance (MDR) and resistance genes against critical antibiotics, particularly quinolones and macrolides, were detected in poultry isolates. This finding poses a significant human health risk via the food chain and underscores the urgency of enhanced biosecurity measures.