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Wu R, Payne M, Zhang L, Lan R. Uncovering the boundaries of Campylobacter species through large-scale phylogenetic and nucleotide identity analyses. mSystems 2024; 9:e0121823. [PMID: 38530055 PMCID: PMC11019964 DOI: 10.1128/msystems.01218-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 02/21/2024] [Indexed: 03/27/2024] Open
Abstract
Campylobacter species are typically helical shaped, Gram-negative, and non-spore-forming bacteria. Species in this genus include established foodborne and animal pathogens as well as emerging pathogens. The accumulation of genomic data from the Campylobacter genus has increased exponentially in recent years, accompanied by the discovery of putative new species. At present, the lack of a standardized species boundary complicates distinguishing established and novel species. We defined the Campylobacter genus core genome (500 loci) using publicly available Campylobacter complete genomes (n = 498) and constructed a core genome phylogeny using 2,193 publicly available Campylobacter genomes to examine inter-species diversity and species boundaries. Utilizing 8,440 Campylobacter genomes representing 33 species and 8 subspecies, we found species delineation based on an average nucleotide identity (ANI) cutoff of 94.2% is consistent with the core genome phylogeny. We identified 60 ANI genomic species that delineated Campylobacter species in concordance with previous comparative genetic studies. All pairwise ANI genomic species pairs had in silico DNA-DNA hybridization scores of less than 70%, supporting their delineation as separate species. We provide the tool Campylobacter Genomic Species typer (CampyGStyper) that assigns ANI genomic species to query genomes based on ANI similarities to medoid genomes from each ANI genomic species with an accuracy of 99.96%. The ANI genomic species definitions proposed here allow consistent species definition in the Campylobacter genus and will facilitate the detection of novel species in the future.IMPORTANCEIn recent years, Campylobacter has gained recognition as the leading cause of bacterial gastroenteritis worldwide, leading to a substantial rise in the collection of genomic data of the Campylobacter genus in public databases. Currently, a standardized Campylobacter species boundary at the genomic level is absent, leading to challenges in detecting emerging pathogens and defining putative novel species within this genus. We used a comprehensive representation of genomes of the Campylobacter genus to construct a core genome phylogenetic tree. Furthermore, we found an average nucleotide identity (ANI) of 94.2% as the optimal cutoff to define the Campylobacter species. Using this cutoff, we identified 60 ANI genomic species which provided a standardized species definition and nomenclature. Importantly, we have developed Campylobacter Genomic Species typer (CampyGStyper), which can robustly and accurately assign these ANI genomic species to Campylobacter genomes, thereby aiding pathogen surveillance and facilitating evolutionary and epidemiological studies of existing and emerging pathogens in the genus Campylobacter.
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Affiliation(s)
- Ruochen Wu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Michael Payne
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Li Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
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2
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Ienes-Lima J, Becerra R, Logue CM. Comparative genomic analysis of Campylobacter hepaticus genomes associated with spotty liver disease, Georgia, United States. Front Microbiol 2023; 14:1215769. [PMID: 37455739 PMCID: PMC10343453 DOI: 10.3389/fmicb.2023.1215769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 06/08/2023] [Indexed: 07/18/2023] Open
Abstract
Campylobacter hepaticus has re-emerged as an important cause of disease in egg laying birds worldwide, resulting in morbidity, mortality, and significant losses in eggs for the breeding and table egg laying industries. Although birds may appear asymptomatic, the disease is characterized by spots on the liver of birds and histopathological analysis reveals multifocal fibrogranulocytic necrotizing hepatitis microscopically. The re-emergence of C. hepaticus may be linked with housing practices as the disease appears more prevalent in pasture raised birds with outside exposure. Here we describe, the whole genome sequences and comparative analysis of four C. hepaticus genomes associated with an outbreak on pasture raised breeders from a farm in Georgia, United States. All four genomes were relatively similar in size and virulence genes harbored. Using these genomes, comparison with current C. hepaticus genomes available in NCBI and other databases and other members of the Campylobacter species was carried out. Using current tools available, virulence gene factor content was compared, and it was found that different tools lead to different numbers of factors identified. The four genomes from this study were relatively similar to C. hepaticus HV10 the type strain from Australia but differed from the other sequenced US strains from Iowa and Florida. C. hepaticus was found to have an overall lower gene content for genes associated with virulence and iron acquisition compared to other Campylobacter genomes and appears to cluster differently than UK genomes on phylogenetic analysis, suggesting the emergence of two lineages of C. hepaticus. This analysis provides valuable insight into the emerging pathogen C. hepaticus, its virulence factors and traits associated with disease in poultry production in the US, potentially providing insight into targets for its control and treatment for laying birds. Our analysis also confirms genes associated with iron acquisition are limited and the presence of the multidrug efflux pump CmeABC in C. hepaticus which may promote survival and persistence in the host niche - the chicken liver/bile. One unique aspect of this study was the finding of a close genetic relationship between C. hepaticus and Campylobacter fetus species and evidence of genome reduction in relation to host niche specificity.
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3
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Günther E, Moore R, Rautenschlein S. Investigation of Spotty Liver Disease and Campylobacter hepaticus in Layer Flocks-A Field Study. Avian Dis 2023; 67:202-208. [PMID: 37556300 DOI: 10.1637/aviandiseases-d-22-00091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/24/2023] [Indexed: 08/11/2023]
Abstract
Campylobacter hepaticus (C. hepaticus) was recently discovered as the causative agent of Spotty Liver Disease (SLD). SLD affects laying hens and causes significant economic losses in egg production in several countries throughout the world. Field observations reveal that cases of SLD appear with a high risk of reoccurrence, specifically in free-range and organic brown-feathered layer lines. Possible factors contributing to the development of SLD still have to be elucidated. In this field study, one free range (Flock 1) and one organic flock (Flock 2) of brown laying hens kept on farms with a history of clinical SLD were monitored for C. hepaticus colonization, clinical signs, and egg production from 16 to 79 wk of age on the first farm and from 17 to 83 wk of age on the other. The flocks showed a significant drop in egg production at 32 to 39 or 56 wk of age, respectively, which was associated with macroscopically visible liver lesions typical for SLD. Interestingly, in both cases observed clinical disease was linked to a stressful event: heat stress for Flock 1 and respiratory symptoms for Flock 2. C. hepaticus was detected by PCR during the acute phase of the disease in Flock 1. At 50 wk after the initial clinical outbreak had waned, C. hepaticus was still able to be isolated by culture in this flock. This clearly demonstrates that C. hepaticus persists either in the birds or their environment. We speculate that this long persistence may favor chronic SLD in affected flocks and the reoccurrence of SLD in subsequent flocks. Clinically less severe SLD outbreaks may be observed after re-exposure of clinically recovered flocks.
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Affiliation(s)
- Ella Günther
- Clinic for Poultry, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Rob Moore
- School of Science, RM1T University, Bundoora West Campus, Bundoora, VIC, Australia
| | - Silke Rautenschlein
- Clinic for Poultry, University of Veterinary Medicine Hannover, 30559 Hannover, Germany,
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4
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Bonnefous C, Collin A, Guilloteau LA, Guesdon V, Filliat C, Réhault-Godbert S, Rodenburg TB, Tuyttens FAM, Warin L, Steenfeldt S, Baldinger L, Re M, Ponzio R, Zuliani A, Venezia P, Väre M, Parrott P, Walley K, Niemi JK, Leterrier C. Welfare issues and potential solutions for laying hens in free range and organic production systems: A review based on literature and interviews. Front Vet Sci 2022; 9:952922. [PMID: 35990274 PMCID: PMC9390482 DOI: 10.3389/fvets.2022.952922] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
In free-range and organic production systems, hens can make choices according to their needs and desires, which is in accordance with welfare definitions. Nonetheless, health and behavioral problems are also encountered in these systems. The aim of this article was to identify welfare challenges observed in these production systems in the EU and the most promising solutions to overcome these challenges. It is based on a review of published literature and research projects complemented by interviews with experts. We selected EU specific information for welfare problems, however, the selected literature regarding solutions is global. Free range use may increase the risk of infection by some bacteria, viruses and parasites. Preventive methods include avoiding contamination thanks to biosecurity measures and strengthening animals' natural defenses against these diseases which can be based on nutritional means with new diet components such as insect-derived products, probiotics and prebiotics. Phytotherapy and aromatherapy can be used as preventive and curative medicine and vaccines as alternatives to antibiotics and pesticides. Bone quality in pullets and hens prevents keel deviations and is favored by exercise in the outdoor range. Free range use also lead to higher exposure to variable weather conditions and predators, therefore shadow, fences and guard animals can be used to prevent heat stress and predation respectively. Granting a free range provides opportunities for the expression of many behaviors and yet many hens usually stay close to the house. Providing the birds with trees, shelters or attractive plants can increase range use. Small flock sizes, early experiences of enrichment and personality traits have also been found to enhance range use. Severe feather pecking can occur in free range production systems, although flocks using the outdoor area have better plumage than indoors. While many prevention strategies are facilitated in free range systems, the influence of genetics, prenatal and nutritional factors in free range hens still need to be investigated. This review provides information about practices that have been tested or still need to be explored and this information can be used by stakeholders and researchers to help them evaluate the applicability of these solutions for welfare improvement.
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Affiliation(s)
| | - Anne Collin
- INRAE, Université de Tours, BOA, Nouzilly, France
| | | | - Vanessa Guesdon
- JUNIA, Comportement Animal et Systèmes d'Elevage, Lille, France
| | | | | | - T. Bas Rodenburg
- Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Frank A. M. Tuyttens
- ILVO, Instituut voor Landbouw-, Visserij- en Voedingsonderzoek, Melle, Belgium
- Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | | | - Sanna Steenfeldt
- Department of Animal Science, Aarhus University, Aarhus, Denmark
| | | | - Martina Re
- AIAB, Associazone Italiana per l'Agricultura Biologica, Rome, Italy
| | | | - Anna Zuliani
- Veterinari Senza Frontiere Italia, Sede c/o Istituto Zooprofilattico Sperimentale delle Venezie viale dell'Università, Padova, Italy
| | - Pietro Venezia
- Veterinari Senza Frontiere Italia, Sede c/o Istituto Zooprofilattico Sperimentale delle Venezie viale dell'Università, Padova, Italy
| | - Minna Väre
- Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Helsinki, Finland
| | | | - Keith Walley
- Harper Adams University, Newport, United Kingdom
| | - Jarkko K. Niemi
- Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Seinäjoki, Finland
| | - Christine Leterrier
- CNRS, IFCE, INRAE, Université de Tours, PRC, Nouzilly, France
- *Correspondence: Christine Leterrier
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van Vliet AHM, Charity OJ, Reuter M. A Campylobacter integrative and conjugative element with a CRISPR-Cas9 system targeting competing plasmids: a history of plasmid warfare? Microb Genom 2021; 7. [PMID: 34766904 PMCID: PMC8743540 DOI: 10.1099/mgen.0.000729] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Microbial genomes are highly adaptable, with mobile genetic elements (MGEs) such as integrative conjugative elements (ICEs) mediating the dissemination of new genetic information throughout bacterial populations. This is countered by defence mechanisms such as CRISPR-Cas systems, which limit invading MGEs by sequence-specific targeting. Here we report the distribution of the pVir, pTet and PCC42 plasmids and a new 70–129 kb ICE (CampyICE1) in the foodborne bacterial pathogens Campylobacter jejuni and Campylobacter coli. CampyICE1 contains a degenerated Type II-C CRISPR system consisting of a sole Cas9 protein, which is distinct from the previously described Cas9 proteins from C. jejuni and C. coli. CampyICE1 is conserved in structure and gene order, containing blocks of genes predicted to be involved in recombination, regulation and conjugation. CampyICE1 was detected in 134/5829 (2.3 %) C. jejuni genomes and 92/1347 (6.8 %) C. coli genomes. Similar ICEs were detected in a number of non-jejuni/coli Campylobacter species, although these lacked a CRISPR-Cas system. CampyICE1 carries three separate short CRISPR spacer arrays containing a combination of 108 unique spacers and 16 spacer-variant families. A total of 69 spacers and 10 spacer-variant families (63.7 %) were predicted to target Campylobacter plasmids. The presence of a functional CampyICE1 Cas9 protein and matching anti-plasmid spacers was associated with the absence of the pVir, pTet and pCC42 plasmids (188/214 genomes, 87.9 %), suggesting that the CampyICE1-encoded CRISPR-Cas has contributed to the exclusion of competing plasmids. In conclusion, the characteristics of the CRISPR-Cas9 system on CampyICE1 suggests a history of plasmid warfare in Campylobacter.
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Affiliation(s)
- Arnoud H M van Vliet
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - Oliver J Charity
- Quadram Institute Bioscience, Microbes in the Food Chain programme, Norwich, UK
| | - Mark Reuter
- Quadram Institute Bioscience, Microbes in the Food Chain programme, Norwich, UK
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6
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Young P, Tarce P, Adhikary S, Connolly J, Crawshaw T, Ghorashi SA. Evaluation of high-resolution melt curve analysis for rapid differentiation of Campylobacter hepaticus from other species in birds. PLoS One 2021; 16:e0251328. [PMID: 33984000 PMCID: PMC8118346 DOI: 10.1371/journal.pone.0251328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/24/2021] [Indexed: 11/18/2022] Open
Abstract
Spotty liver disease (SLD) is a bacterial disease of chicken, causing mortalities and reduction in egg production, hence, contributing to economic loss in the poultry industry. The causative agent of SLD has only recently been identified as a novel Campylobacter species, Campylobacter hepaticus. Specific primers were designed from the hsp60 gene of Campylobacter hepaticus and PCR followed by high-resolution melt curve analysis was optimised to detect and differentiate three species of Campylobacter (Campylobacter coli, Campylobacter jejuni and Campylobacter hepaticus). The three Campylobacter species produced a distinct curve profile and was differentiated using HRM curve analysis. The potential of the PCR-HRM curve analysis was shown in the genotyping of 37 Campylobacter isolates from clinical specimens from poultry farms. PCR-HRM curve analysis of DNA extracts from bile samples or cultures from bile samples, were identified as Campylobacter hepaticus and confirmed by DNA sequencing. The DNA sequence analysis of selected samples from each of the three HRM distinctive curves patterns showed that each DNA sequence was associated with a unique melt profile. The potential of the PCR-HRM curve analysis in genotyping of Campylobacter species was also evaluated using faecal specimens from 100 wild birds. The results presented in this study indicate that PCR followed by HRM curve analysis provides a rapid and robust technique for genotyping of Campylobacter species using either bacterial cultures or clinical specimens.
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Affiliation(s)
- Petrina Young
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Pol Tarce
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Sadhana Adhikary
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Joanne Connolly
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Tim Crawshaw
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- School of Veterinary Sciences, Massey University, Tennent Drive, Palmerston North, New Zealand
| | - Seyed A. Ghorashi
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- * E-mail:
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7
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Complete Genome Sequence of Campylobacter hepaticus Strain UF2019SK1, Isolated from a Commercial Layer Flock in the United States. Microbiol Resour Announc 2021; 10:10/12/e01446-20. [PMID: 33766908 PMCID: PMC7996467 DOI: 10.1128/mra.01446-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The thermophilic Campylobacter species Campylobacter hepaticus is the causative agent of spotty liver disease (SLD) in chickens. This announcement describes the complete genome sequence of C. hepaticus strain UF2019SK1, isolated from the liver of a commercial layer chicken with SLD in the United States. The thermophilic Campylobacter species Campylobacter hepaticus is the causative agent of spotty liver disease (SLD) in chickens. This announcement describes the complete genome sequence of C. hepaticus strain UF2019SK1, isolated from the liver of a commercial layer chicken with SLD in the United States.
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8
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Dai L, Sahin O, Grover M, Zhang Q. New and alternative strategies for the prevention, control, and treatment of antibiotic-resistant Campylobacter. Transl Res 2020; 223:76-88. [PMID: 32438073 PMCID: PMC7423705 DOI: 10.1016/j.trsl.2020.04.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/10/2020] [Accepted: 04/11/2020] [Indexed: 12/24/2022]
Abstract
Campylobacter is an enteric pathogen and a leading bacterial cause of diarrhea worldwide. It is widely distributed in food animal species and is transmitted to humans primarily through the foodborne route. While generally causing self-limited diarrhea in humans, Campylobacter may induce severe or systemic infections in immunocompromised or young/elderly patients, which often requires antibiotic therapy with the first-line antibiotics including fluoroquinolones and macrolides. Over the past decades, Campylobacter has acquired resistance to these clinically significant antibiotics, compromising the effectiveness of antibiotic treatments. To address this concern, many studies have been conducted to advance novel and alternative measures to control antibiotic-resistant Campylobacter in animal reservoirs and in the human host. Although some of these undertakings have yielded promising results, efficacious and reliable alternative approaches are yet to be developed. In this review article, we will describe Campylobacter-associated disease spectrums and current treatment options, discuss the state of antibiotic resistance and alternative therapies, and provide an evaluation of various approaches that are being developed to control Campylobacter infections in animal reservoirs and the human host.
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Affiliation(s)
- Lei Dai
- Departments of Veterinary Microbiology and Preventive Medicine
| | - Orhan Sahin
- Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, United States 50011
| | - Madhusudan Grover
- Division of Gastroenterology and Hepatology, Enteric NeuroScience Program, Mayo Clinic, Rochester, Minnesota, United States 55902
| | - Qijing Zhang
- Departments of Veterinary Microbiology and Preventive Medicine.
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9
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Cheng Y, Zhang W, Lu Q, Wen G, Zhao Z, Luo Q, Shao H, Zhang T. Point Deletion or Insertion in CmeR-Box, A2075G Substitution in 23S rRNA, and Presence of erm(B) Are Key Factors of Erythromycin Resistance in Campylobacter jejuni and Campylobacter coli Isolated From Central China. Front Microbiol 2020; 11:203. [PMID: 32194516 PMCID: PMC7062675 DOI: 10.3389/fmicb.2020.00203] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 01/29/2020] [Indexed: 12/11/2022] Open
Abstract
Campylobacter jejuni and Campylobacter coli are major food-borne pathogens that cause bacterial gastroenteritis in humans, and poultry is considered as their most important reservoir. Macrolides, such as erythromycin, are the first-line choice for treatment of campylobacteriosis. In this study, of the 143 Campylobacter isolates recovered from poultry in central China during 2015–2017, 25.2% were erythromycin resistant. A2075G substitution in 23S ribosomal RNA (rRNA) and ribosomal methylase encoded by erm(B) were found in 4.2 and 4.9% isolates, respectively, and correlated with erythromycin resistance. The polymorphisms of CmeR-Box were also analyzed in our isolates. Among them, 9.1% isolates harbored a point deletion or insertion within the CmeR-Box, and we first showed that point deletion or insertion, but not substitution, in CmeR-Box led to high expression of cmeABC, which was significantly associated with erythromycin resistance (p < 0.05). These results suggest that point deletion or insertion in CmeR-Box, A2075G substitution in 23S rRNA, and presence of erm(B) are three main factors to erythromycin resistance in C. jejuni and C. coli.
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Affiliation(s)
- Yiluo Cheng
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Wenting Zhang
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Qin Lu
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Guoyuan Wen
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Zhongzheng Zhao
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Qingping Luo
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Huabin Shao
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Tengfei Zhang
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan, China
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Phung C, Vezina B, Anwar A, Wilson T, Scott PC, Moore RJ, Van TTH. Campylobacter hepaticus, the Cause of Spotty Liver Disease in Chickens: Transmission and Routes of Infection. Front Vet Sci 2020; 6:505. [PMID: 32010715 PMCID: PMC6974796 DOI: 10.3389/fvets.2019.00505] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 12/20/2019] [Indexed: 01/26/2023] Open
Abstract
The epidemiology of Spotty Liver Disease (SLD) was investigated by assaying 1,840 samples collected from layer chickens and the environment in poultry farms across Australia for the presence of Campylobacter hepaticus, the agent responsible SLD in chickens. A C. hepaticus specific PCR and bacterial culture were used. Results showed that birds could be infected with C. hepaticus up to 8 weeks before clinical SLD was manifested. In addition, birds could be infected long before laying starts, as young as 12 weeks old, but the peak period for SLD outbreaks was when the birds were 26-27 weeks old. Campylobacter hepaticus DNA was detected in motile organisms such as wild birds and rats and so these organisms may be vectors for C. hepaticus dissemination. Moreover, water, soil, mites, flies, and dust samples from SLD infected farms were also found to be PCR-positive for C. hepaticus DNA. However, it still remains to be determined whether these environmental sources carry any viable C. hepaticus. The indications from this study are that environmental sources are a likely transmission source of C. hepaticus. Therefore, biosecurity practices need to be strictly followed to prevent the spread of SLD amongst and between flocks. Also, a rapid, molecular detection method such as PCR should be used as to monitor for C. hepaticus presence in flocks before clinical disease is apparent, and therefore inform the use of biosecurity and therapeutic measures to help prevent SLD outbreaks.
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Affiliation(s)
- Canh Phung
- School of Science, RMIT University, Bundoora West Campus, Bundoora, VIC, Australia
| | - Ben Vezina
- School of Science, RMIT University, Bundoora West Campus, Bundoora, VIC, Australia
| | - Arif Anwar
- Scolexia Pty Ltd., Moonee Ponds, VIC, Australia
| | | | | | - Robert J Moore
- School of Science, RMIT University, Bundoora West Campus, Bundoora, VIC, Australia
| | - Thi Thu Hao Van
- School of Science, RMIT University, Bundoora West Campus, Bundoora, VIC, Australia
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