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Elmi A, Nasher F, Dorrell N, Wren B, Gundogdu O. Revisiting Campylobacter jejuni Virulence and Fitness Factors: Role in Sensing, Adapting, and Competing. Front Cell Infect Microbiol 2021; 10:607704. [PMID: 33614526 PMCID: PMC7887314 DOI: 10.3389/fcimb.2020.607704] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/11/2020] [Indexed: 12/18/2022] Open
Abstract
Campylobacter jejuni is the leading cause of bacterial foodborne gastroenteritis world wide and represents a major public health concern. Over the past two decades, significant progress in functional genomics, proteomics, enzymatic-based virulence profiling (EBVP), and the cellular biology of C. jejuni have improved our basic understanding of this important pathogen. We review key advances in our understanding of the multitude of emerging virulence factors that influence the outcome of C. jejuni–mediated infections. We highlight, the spatial and temporal dynamics of factors that promote C. jejuni to sense, adapt and survive in multiple hosts. Finally, we propose cohesive research directions to obtain a comprehensive understanding of C. jejuni virulence mechanisms.
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Affiliation(s)
- Abdi Elmi
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Fauzy Nasher
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nick Dorrell
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Brendan Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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McKenna A, Ijaz UZ, Kelly C, Linton M, Sloan WT, Green BD, Lavery U, Dorrell N, Wren BW, Richmond A, Corcionivoschi N, Gundogdu O. Impact of industrial production system parameters on chicken microbiomes: mechanisms to improve performance and reduce Campylobacter. Microbiome 2020; 8:128. [PMID: 32907634 PMCID: PMC7488076 DOI: 10.1186/s40168-020-00908-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/17/2020] [Indexed: 05/04/2023]
Abstract
BACKGROUND The factors affecting host-pathogen ecology in terms of the microbiome remain poorly studied. Chickens are a key source of protein with gut health heavily dependent on the complex microbiome which has key roles in nutrient assimilation and vitamin and amino acid biosynthesis. The chicken gut microbiome may be influenced by extrinsic production system parameters such as Placement Birds/m2 (stocking density), feed type and additives. Such parameters, in addition to on-farm biosecurity may influence performance and also pathogenic bacterial numbers such as Campylobacter. In this study, three different production systems 'Normal' (N), 'Higher Welfare' (HW) and 'Omega-3 Higher Welfare' (O) were investigated in an industrial farm environment at day 7 and day 30 with a range of extrinsic parameters correlating performance with microbial dynamics and Campylobacter presence. RESULTS Our data identified production system N as significantly dissimilar from production systems HW and O when comparing the prevalence of genera. An increase in Placement Birds/m2 density led to a decrease in environmental pressure influencing the microbial community structure. Prevalence of genera, such as Eisenbergiella within HW and O, and likewise Alistipes within N were representative. These genera have roles directly relating to energy metabolism, amino acid, nucleotide and short chain fatty acid (SCFA) utilisation. Thus, an association exists between consistent and differentiating parameters of the production systems that affect feed utilisation, leading to competitive exclusion of genera based on competition for nutrients and other factors. Campylobacter was identified within specific production system and presence was linked with the increased diversity and increased environmental pressure on microbial community structure. Addition of Omega-3 though did alter prevalence of specific genera, in our analysis did not differentiate itself from HW production system. However, Omega-3 was linked with a positive impact on weight gain. CONCLUSIONS Overall, our results show that microbial communities in different industrial production systems are deterministic in elucidating the underlying biological confounders, and these recommendations are transferable to farm practices and diet manipulation leading to improved performance and better intervention strategies against Campylobacter within the food chain. Video Abstract.
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Affiliation(s)
- Aaron McKenna
- Moy Park, 39 Seagoe Industrial Estate, Portadown, Craigavon, Co. Armagh, BT63 5QE, UK
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Biological Sciences Building, Belfast, BT9 5DL, Northern Ireland
| | | | - Carmel Kelly
- Food Microbiology Unit, Agri-Food and Biosciences Institute, Newforge Lane, Belfast, BT9 5PX, UK
| | - Mark Linton
- Food Microbiology Unit, Agri-Food and Biosciences Institute, Newforge Lane, Belfast, BT9 5PX, UK
| | - William T Sloan
- School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
| | - Brian D Green
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Biological Sciences Building, Belfast, BT9 5DL, Northern Ireland
| | - Ursula Lavery
- Moy Park, 39 Seagoe Industrial Estate, Portadown, Craigavon, Co. Armagh, BT63 5QE, UK
| | - Nick Dorrell
- Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Brendan W Wren
- Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Anne Richmond
- Moy Park, 39 Seagoe Industrial Estate, Portadown, Craigavon, Co. Armagh, BT63 5QE, UK
| | - Nicolae Corcionivoschi
- Food Microbiology Unit, Agri-Food and Biosciences Institute, Newforge Lane, Belfast, BT9 5PX, UK.
| | - Ozan Gundogdu
- Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
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Stratakos AC, Ijaz UZ, Ward P, Linton M, Kelly C, Pinkerton L, Scates P, McBride J, Pet I, Criste A, Stef D, Couto JM, Sloan WT, Dorrell N, Wren BW, Stef L, Gundogdu O, Corcionivoschi N. In vitro and in vivo characterisation of Listeria monocytogenes outbreak isolates. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106784] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Liaw J, Hong G, Davies C, Elmi A, Sima F, Stratakos A, Stef L, Pet I, Hachani A, Corcionivoschi N, Wren BW, Gundogdu O, Dorrell N. The Campylobacter jejuni Type VI Secretion System Enhances the Oxidative Stress Response and Host Colonization. Front Microbiol 2019; 10:2864. [PMID: 31921044 PMCID: PMC6927950 DOI: 10.3389/fmicb.2019.02864] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 11/26/2019] [Indexed: 12/15/2022] Open
Abstract
The role of the Type VI secretion system (T6SS) in Campylobacter jejuni is poorly understood despite an increasing prevalence of the T6SS in recent C. jejuni isolates in humans and chickens. The T6SS is a contractile secretion machinery capable of delivering effectors that can play a role in host colonization and niche establishment. During host colonization, C. jejuni is exposed to oxidative stress in the host gastrointestinal tract, and in other bacteria the T6SS has been linked with the oxidative stress response. In this study, comparisons of whole genome sequences of a novel human isolate 488 with previously sequenced strains revealed a single highly conserved T6SS cluster shared between strains isolated from humans and chickens. The presence of a functional T6SS in the 488 wild-type strain is indicated by expression of T6SS genes and secretion of the effector TssD. Increased expression of oxidative stress response genes katA, sodB, and ahpC, and increased oxidative stress resistance in 488 wild-type strain suggest T6SS is associated with oxidative stress response. The role of the T6SS in interactions with host cells is explored using in vitro and in vivo models, and the presence of the T6SS is shown to increase C. jejuni cytotoxicity in the Galleria mellonella infection model. In biologically relevant models, the T6SS enhances C. jejuni interactions with and invasion of chicken primary intestinal cells and enhances the ability of C. jejuni to colonize chickens. This study demonstrates that the C. jejuni T6SS provides defense against oxidative stress and enhances host colonization, and highlights the importance of the T6SS during in vivo survival of T6SS-positive C. jejuni strains.
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Affiliation(s)
- Janie Liaw
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Geunhye Hong
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Cadi Davies
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Abdi Elmi
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Filip Sima
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, United Kingdom
| | - Alexandros Stratakos
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, United Kingdom
| | - Lavinia Stef
- Bioengineering of Animal Science Resources, Banat University of Agricultural Sciences and Veterinary Medicine - King Michael the I of Romania, Timisoara, Romania
| | - Ioan Pet
- Bioengineering of Animal Science Resources, Banat University of Agricultural Sciences and Veterinary Medicine - King Michael the I of Romania, Timisoara, Romania
| | - Abderrahman Hachani
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.,The Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Nicolae Corcionivoschi
- Bacteriology Branch, Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, United Kingdom.,Bioengineering of Animal Science Resources, Banat University of Agricultural Sciences and Veterinary Medicine - King Michael the I of Romania, Timisoara, Romania
| | - Brendan W Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Nick Dorrell
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Davies C, Taylor AJ, Elmi A, Winter J, Liaw J, Grabowska AD, Gundogdu O, Wren BW, Kelly DJ, Dorrell N. Sodium Taurocholate Stimulates Campylobacter jejuni Outer Membrane Vesicle Production via Down-Regulation of the Maintenance of Lipid Asymmetry Pathway. Front Cell Infect Microbiol 2019; 9:177. [PMID: 31192166 PMCID: PMC6549495 DOI: 10.3389/fcimb.2019.00177] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 05/09/2019] [Indexed: 12/22/2022] Open
Abstract
Campylobacter jejuni outer membrane vesicles (OMVs) contain numerous virulence-associated proteins including the cytolethal distending toxin and three serine proteases. As C. jejuni lacks the classical virulence-associated secretion systems of other enteric pathogens that deliver effectors directly into target cells, OMVs may have a particularly important role in virulence. C. jejuni OMV production is stimulated by the presence of physiological concentrations of the bile salt sodium taurocholate (ST) through an unknown mechanism. The maintenance of lipid asymmetry (MLA) pathway has been implicated in a novel mechanism for OMV biogenesis, open to regulation by host signals. In this study we investigated the role of the MLA pathway in C. jejuni OMV biogenesis with ST as a potential regulator. OMV production was quantified by analyzing protein and lipid concentrations of OMV preparations and OMV particle counts produced by nanoparticle tracking analysis. Mutation of mlaA which encodes the outer membrane component of the MLA pathway significantly increased OMV production compared to the wild-type strain. Detergent sensitivity and membrane permeability assays confirmed the increased OMV production was not due to changes in membrane stability. The presence of 0.2% (w/v) ST increased wild-type OMV production and reduced OMV size, but did not further stimulate mlaA mutant OMV production or significantly alter mlaA mutant OMV size. qRT-PCR analysis demonstrated that the presence of ST decreased expression of both mlaA and mlaC in C. jejuni wild-type strains 11168 and 488. Collectively the data in this study suggests C. jejuni can regulate OMV production in response to host gut signals through changes in expression of the MLA pathway. As the gut bile composition is dependent on both diet and the microbiota, this study highlights the potential importance of diet and lifestyle factors on the varying disease presentations associated with gut pathogen infection.
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Affiliation(s)
- Cadi Davies
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Aidan J Taylor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Abdi Elmi
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jody Winter
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Janie Liaw
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Anna D Grabowska
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Brendan W Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David J Kelly
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Nick Dorrell
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Ijaz UZ, Sivaloganathan L, McKenna A, Richmond A, Kelly C, Linton M, Stratakos AC, Lavery U, Elmi A, Wren BW, Dorrell N, Corcionivoschi N, Gundogdu O. Comprehensive Longitudinal Microbiome Analysis of the Chicken Cecum Reveals a Shift From Competitive to Environmental Drivers and a Window of Opportunity for Campylobacter. Front Microbiol 2018; 9:2452. [PMID: 30374341 PMCID: PMC6196313 DOI: 10.3389/fmicb.2018.02452] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 09/25/2018] [Indexed: 02/02/2023] Open
Abstract
Chickens are a key food source for humans yet their microbiome contains bacteria that can be pathogenic to humans, and indeed potentially to chickens themselves. Campylobacter is present within the chicken gut and is the leading cause of bacterial foodborne gastroenteritis within humans worldwide. Infection can lead to secondary sequelae such as Guillain-Barré syndrome and stunted growth in children from low-resource areas. Despite the global health impact and economic burden of Campylobacter, how and when Campylobacter appears within chickens remains unclear. The lack of day to day microbiome data with replicates, relevant metadata, and a lack of natural infection studies have delayed our understanding of the chicken gut microbiome and Campylobacter. Here, we performed a comprehensive day to day microbiome analysis of the chicken cecum from day 3 to 35 (12 replicates each day; final n = 379). We combined metadata such as chicken weight and feed conversion rates to investigate what the driving forces are for the microbial changes within the chicken gut over time, and how this relates to Campylobacter appearance within a natural habitat setting. We found a rapidly increasing microbial diversity up to day 12 with variation observed both in terms of genera and abundance, before a stabilization of the microbial diversity after day 20. In particular, we identified a shift from competitive to environmental drivers of microbial community from days 12 to 20 creating a window of opportunity whereby Campylobacter can appear. Campylobacter was identified at day 16 which was 1 day after the most substantial changes in metabolic profiles observed. In addition, microbial variation over time is most likely influenced by the diet of the chickens whereby significant shifts in OTU abundances and beta dispersion of samples often corresponded with changes in feed. This study is unique in comparison to the most recent studies as neither sampling was sporadic nor Campylobacter was artificially introduced, thus the experiments were performed in a natural setting. We believe that our findings can be useful for future intervention strategies and help reduce the burden of Campylobacter within the food chain.
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Affiliation(s)
- Umer Zeeshan Ijaz
- School of Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Lojika Sivaloganathan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Carmel Kelly
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, United Kingdom
| | - Mark Linton
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, United Kingdom
| | | | | | - Abdi Elmi
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Brendan W. Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nick Dorrell
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nicolae Corcionivoschi
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, United Kingdom
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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7
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Ugarte-Ruiz M, Domínguez L, Corcionivoschi N, Wren BW, Dorrell N, Gundogdu O. Exploring the oxidative, antimicrobial and genomic properties of Campylobacter jejuni strains isolated from poultry. Res Vet Sci 2018; 119:170-175. [PMID: 29957495 DOI: 10.1016/j.rvsc.2018.06.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 04/25/2018] [Accepted: 06/13/2018] [Indexed: 11/19/2022]
Abstract
Campylobacter jejuni is the leading cause of food-borne bacterial enteritis in humans, with contaminated poultry products considered the main source of infection. To survive the food chain, C. jejuni utilizes multiple defense mechanisms that counter oxidative and aerobic stresses. In this study, we phenotypically characterised 63 C. jejuni strains with oxidative stress survival and antimicrobial susceptibility testing to investigate correlations between these two phenotypes against the source of the strains and the presence of the MarR regulators RrpA and RrpB which have a role in regulating the response to oxidative and aerobic stress. C. jejuni strains isolated from meat and neck skin displayed the highest resistance to oxidative stress. In addition, C. jejuni strains that have an rrpA+rrpB- profile exhibit increased resistance to oxidative stress and to antimicrobials. Here we establish a preliminary link between the distribution of RrpA and RrpB and the increased resistance to antimicrobials. This study provides insight into how the genotypic make up of C. jejuni can influence the ability of the bacterium to survive within areas of high oxygen stress, such as the food chain, and subsequently can have a potential negative impact on human health.
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Affiliation(s)
- Maria Ugarte-Ruiz
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.
| | - Lucas Domínguez
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain; Facultad de Veterinaria, Universidad Complutense Madrid, Madrid, Spain.
| | | | - Brendan W Wren
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
| | - Nick Dorrell
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
| | - Ozan Gundogdu
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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Elmi A, Dorey A, Watson E, Jagatia H, Inglis NF, Gundogdu O, Bajaj-Elliott M, Wren BW, Smith DGE, Dorrell N. The bile salt sodium taurocholate induces Campylobacter jejuni outer membrane vesicle production and increases OMV-associated proteolytic activity. Cell Microbiol 2017; 20. [PMID: 29205766 DOI: 10.1111/cmi.12814] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 02/06/2023]
Abstract
Campylobacter jejuni, the leading cause of bacterial acute gastroenteritis worldwide, secretes an arsenal of virulence-associated proteins within outer membrane vesicles (OMVs). C. jejuni OMVs contain three serine proteases (HtrA, Cj0511, and Cj1365c) that cleave the intestinal epithelial cell (IEC) tight and adherens junction proteins occludin and E-cadherin, promoting enhanced C. jejuni adhesion to and invasion of IECs. C. jejuni OMVs also induce IECs innate immune responses. The bile salt sodium taurocholate (ST) is sensed as a host signal to coordinate the activation of virulence-associated genes in the enteric pathogen Vibrio cholerae. In this study, the effect of ST on C. jejuni OMVs was investigated. Physiological concentrations of ST do not have an inhibitory effect on C. jejuni growth until the early stationary phase. Coculture of C. jejuni with 0.1% or 0.2% (w/v) ST stimulates OMV production, increasing both lipid and protein concentrations. C. jejuni ST-OMVs possess increased proteolytic activity and exhibit a different protein profile compared to OMVs isolated in the absence of ST. ST-OMVs exhibit enhanced cytotoxicity and immunogenicity to T84 IECs and enhanced killing of Galleria mellonella larvae. ST increases the level of mRNA transcripts of the OMVs-associated serine protease genes and the cdtABC operon that encodes the cytolethal distending toxin. Coculture with ST significantly enhances the OMVs-induced cleavage of E-cadherin and occludin. C. jejuni OMVs also cleave the major endoplasmic reticulum chaperone protein BiP/GRP78 and this activity is associated with the Cj1365c protease. These data suggest that C. jejuni responds to the presence of physiological concentrations of the bile salt ST that increases OMV production and the synthesis of virulence-associated factors that are secreted within the OMVs. We propose that these events contribute to pathogenesis.
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Affiliation(s)
- Abdi Elmi
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Amber Dorey
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Heena Jagatia
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Ozan Gundogdu
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Mona Bajaj-Elliott
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, UK
| | - Brendan W Wren
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - David G E Smith
- School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, UK
| | - Nick Dorrell
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Kazakos EI, Dorrell N, Polyzos SA, Deretzi G, Kountouras J. Comment on "Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics". World J Gastroenterol 2017; 23:6194-6196. [PMID: 28970736 PMCID: PMC5597512 DOI: 10.3748/wjg.v23.i33.6194] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/27/2017] [Accepted: 07/22/2017] [Indexed: 02/06/2023] Open
Abstract
Attaran et al[1] have recently shown that decreased susceptibility of established Helicobacter pylori (H. pylori) biofilms to specific antibiotics, was associated with the overtly enhanced transcription of two efflux pump genes, hp1165 and hefA, involved in specific resistance to tetracycline and multiple antibiotics, respectively. Apart from antibiotic exposure, secretion of multiple antimicrobial peptides, such as human β-defensins (hβDs), by the gastric epithelium upon Hp challenge, may act as early triggering events that positively impact biofilm formation and thus, antibiotic resistance. In this regard, we undertook genomic transcriptional studies using Hp 26695 strain following exposure to sublethal, similar to those present in the gastric niche, concentrations of hβDs in an attempt to provide preliminary data regarding possible mechanisms of immune evasion and selective sensitivity of Hp. Our preliminary results indicate that hβD exposure ignites a rapid response that is largely due to the activation of several, possibly interconnected transcriptional regulatory networks - origons - that ultimately coordinate cellular processes needed to maintain homeostasis and successful adaptation of the bacterium in the gastric environment. In addition, we have shown that both antibiotic and hβD resistance are mediated by dedicated periplasmic transporters, including the aforementioned efflux pump genes hp1165 and hefA, involved in active export of antibiotics from the cell membrane and/or, as recently suggested, substrate sensing and signalling. Furthermore, it appears that sublethal doses of hβDs may enhance biofilm formation by the sustained expression of, mainly, quorum sensing-related genes. In conclusion, we provide additional data regarding the role of specific innate immune molecules in antibiotic cross-resistance mechanisms that may deepen our understanding in the context of the development of novel eradication regimens.
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Affiliation(s)
- Evangelos I Kazakos
- Department of Medicine, the Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, 54642 Thessaloniki, Greece
| | - Nick Dorrell
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Stergios A Polyzos
- Department of Medicine, the Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, 54642 Thessaloniki, Greece
| | - Georgia Deretzi
- Department of Neurology, Multiple Sclerosis Unit, Papageorgiou General Hospital, 54629 Thessaloniki, Greece
| | - Jannis Kountouras
- Department of Medicine, the Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, 54642 Thessaloniki, Greece
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Kelly C, Gundogdu O, Pircalabioru G, Cean A, Scates P, Linton M, Pinkerton L, Magowan E, Stef L, Simiz E, Pet I, Stewart S, Stabler R, Wren B, Dorrell N, Corcionivoschi N. The In Vitro and In Vivo Effect of Carvacrol in Preventing Campylobacter Infection, Colonization and in Improving Productivity of Chicken Broilers. Foodborne Pathog Dis 2017; 14:341-349. [PMID: 28398869 DOI: 10.1089/fpd.2016.2265] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The current trend in reducing the antibiotic usage in animal production imposes urgency in the identification of novel biocides. The essential oil carvacrol, for example, changes the morphology of the cell and acts against a variety of targets within the bacterial membranes and cytoplasm, and our in vitro results show that it reduces adhesion and invasion of chicken intestinal primary cells and also biofilm formation. A trial was conducted to evaluate the effects of dietary supplementation of carvacrol at four concentrations (0, 120, 200, and 300 mg/kg of diet) on the performance of Lactobacillus spp., Escherichia coli, Campylobacter spp., and broilers. Each of the four diets was fed to three replicates/trial of 50 chicks each from day 0 to 35. Our results show that carvacrol linearly decreased feed intake, feed conversion rates and increased body weight at all levels of supplementation. Plate count analysis showed that Campylobacter spp. was only detected at 35 days in the treatment groups compared with the control group where the colonization occurred at 21 days. The absence of Campylobacter spp. at 21 days in the treatment groups was associated with a significant increase in the relative abundance of Lactobacillus spp. Also, carvacrol was demonstrated to have a significant effect on E. coli numbers in the cecum of the treatment groups, at all supplementation levels. In conclusion, this study shows for the first time that at different concentrations, carvacrol can delay Campylobacter spp., colonization of chicken broilers, by inducing changes in gut microflora, and it demonstrates promise as an alternative to the use of antibiotics.
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Affiliation(s)
- Carmel Kelly
- 1 Veterinary Science Division, Bacteriology Branch, Agri-Food and Biosciences Institute , Belfast, United Kingdom
| | - Ozan Gundogdu
- 2 London School of Hygiene and Tropical Medicine , London, United Kingdom
| | | | - Ada Cean
- 4 School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania , Timisoara, Romania
| | - Pam Scates
- 1 Veterinary Science Division, Bacteriology Branch, Agri-Food and Biosciences Institute , Belfast, United Kingdom
| | - Mark Linton
- 1 Veterinary Science Division, Bacteriology Branch, Agri-Food and Biosciences Institute , Belfast, United Kingdom
| | - Laurette Pinkerton
- 1 Veterinary Science Division, Bacteriology Branch, Agri-Food and Biosciences Institute , Belfast, United Kingdom
| | - Elizabeth Magowan
- 5 Sustainable Agri-Food Sciences Division, Agriculture Branch, Agri-Food and Biosciences Institute, Hillsborough, United Kingdom
| | - Lavinia Stef
- 4 School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania , Timisoara, Romania
| | - Eliza Simiz
- 4 School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania , Timisoara, Romania
| | - Ioan Pet
- 4 School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania , Timisoara, Romania
| | - Sharon Stewart
- 1 Veterinary Science Division, Bacteriology Branch, Agri-Food and Biosciences Institute , Belfast, United Kingdom
| | - Richard Stabler
- 2 London School of Hygiene and Tropical Medicine , London, United Kingdom
| | - Brendan Wren
- 2 London School of Hygiene and Tropical Medicine , London, United Kingdom
| | - Nick Dorrell
- 2 London School of Hygiene and Tropical Medicine , London, United Kingdom
| | - Nicolae Corcionivoschi
- 1 Veterinary Science Division, Bacteriology Branch, Agri-Food and Biosciences Institute , Belfast, United Kingdom .,4 School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania , Timisoara, Romania
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11
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Gundogdu O, da Silva DT, Mohammad B, Elmi A, Wren BW, van Vliet AHM, Dorrell N. The Campylobacter jejuni Oxidative Stress Regulator RrpB Is Associated with a Genomic Hypervariable Region and Altered Oxidative Stress Resistance. Front Microbiol 2016; 7:2117. [PMID: 28082970 PMCID: PMC5183652 DOI: 10.3389/fmicb.2016.02117] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/15/2016] [Indexed: 11/25/2022] Open
Abstract
Campylobacter jejuni is the leading cause of bacterial foodborne diarrhoeal disease worldwide. Despite the microaerophilic nature of the bacterium, C. jejuni can survive the atmospheric oxygen conditions in the environment. Bacteria that can survive either within a host or in the environment like C. jejuni require variable responses to survive the stresses associated with exposure to different levels of reactive oxygen species. The MarR-type transcriptional regulators RrpA and RrpB have recently been shown to play a role in controlling both the C. jejuni oxidative and aerobic stress responses. Analysis of 3,746 C. jejuni and 486 C. coli genome sequences showed that whilst rrpA is present in over 99% of C. jejuni strains, the presence of rrpB is restricted and appears to correlate with specific MLST clonal complexes (predominantly ST-21 and ST-61). C. coli strains in contrast lack both rrpA and rrpB. In C. jejuni rrpB+ strains, the rrpB gene is located within a variable genomic region containing the IF subtype of the type I Restriction-Modification (hsd) system, whilst this variable genomic region in C. jejuni rrpB- strains contains the IAB subtype hsd system and not the rrpB gene. C. jejuni rrpB- strains exhibit greater resistance to peroxide and aerobic stress than C. jejuni rrpB+ strains. Inactivation of rrpA resulted in increased sensitivity to peroxide stress in rrpB+ strains, but not in rrpB- strains. Mutation of rrpA resulted in reduced killing of Galleria mellonella larvae and enhanced biofilm formation independent of rrpB status. The oxidative and aerobic stress responses of rrpB- and rrpB+ strains suggest adaptation of C. jejuni within different hosts and niches that can be linked to specific MLST clonal complexes.
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Affiliation(s)
- Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
| | - Daiani T da Silva
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
| | - Banaz Mohammad
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
| | - Abdi Elmi
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
| | - Brendan W Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
| | - Arnoud H M van Vliet
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey Guildford, UK
| | - Nick Dorrell
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
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12
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Elmi A, Nasher F, Jagatia H, Gundogdu O, Bajaj-Elliott M, Wren B, Dorrell N. Campylobacter jejuni outer membrane vesicle-associated proteolytic activity promotes bacterial invasion by mediating cleavage of intestinal epithelial cell E-cadherin and occludin. Cell Microbiol 2015; 18:561-72. [PMID: 26451973 DOI: 10.1111/cmi.12534] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/08/2015] [Accepted: 09/28/2015] [Indexed: 12/15/2022]
Abstract
Outer membrane vesicles (OMVs) play an important role in the pathogenicity of Gram-negative bacteria. Campylobacter jejuni produces OMVs that trigger IL-8, IL-6, hBD-3 and TNF-α responses from T84 intestinal epithelial cells and are cytotoxic to Caco-2 IECs and Galleria mellonella larvae. Proteomic analysis of 11168H OMVs identified the presence of three proteases, HtrA, Cj0511 and Cj1365c. In this study, 11168H OMVs were shown to possess proteolytic activity that was reduced by pretreatment with specific serine protease inhibitors. OMVs isolated from 11168H htrA, Cj0511 or Cj1365c mutants possess significantly reduced proteolytic activity. 11168H OMVs are able to cleave both E-cadherin and occludin, but this cleavage is reduced with OMVs pretreated with serine protease inhibitors and also with OMVs isolated from htrA or Cj1365c mutants. Co-incubation of T84 monolayers with 11168H OMVs results in a visible reduction in both E-cadherin and occludin. The addition of 11168H OMVs to the co-culture of live 11168H bacteria with T84 cells results in enhanced levels of bacterial adhesion and invasion in a time-dependent and dose-dependent manner. Further investigation of the cleavage of host cell structural proteins by C. jejuni OMVs should enhance our understanding of the interactions of this important pathogen with intestinal epithelial cells.
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Affiliation(s)
- Abdi Elmi
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Fauzy Nasher
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Heena Jagatia
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Mona Bajaj-Elliott
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Brendan Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Nick Dorrell
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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13
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Corcionivoschi N, Gundogdu O, Moran L, Kelly C, Scates P, Stef L, Cean A, Wren B, Dorrell N, Madden RH. Virulence characteristics of hcp (+) Campylobacter jejuni and Campylobacter coli isolates from retail chicken. Gut Pathog 2015. [PMID: 26207145 PMCID: PMC4511981 DOI: 10.1186/s13099-015-0067-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Background Recently the Type VI secretion
system (T6SS), which can play a significant role in bacterial survival and pathogenesis, was reported in Campylobacter spp., having the hcp gene as a key component. Methods Campylobacteriosis is associated with the consumption of infected chicken meat. Our study aimed to explore the presence of T6SS in C. jejuni (n = 59) and C. coli (n = 57) isolates, from retail raw chicken and to investigate their pathogenic potential. The hcp gene was used as an indicator for the T6SS presence. Results Using multiplex PCR we have identified a significantly higher prevalence of hcp in C. coli isolates (56.1%) than in C. jejuni (28.8%) and AFLP analysis of the isolates showed a high degree of genetic similarity between the isolates carrying the hcp gene. Genome sequencing data showed that 84.3% of the C. coli and 93.7% of the C. jejuni isolates had all 13 T6SS open reading frames. Moreover, the virulence characteristics of hcp + isolates, including motility and the ability to invade human intestinal epithelial cells in vitro, were significantly greater than in the control strain C. jejuni 12502; a human isolate which is hcp positive. Conclusion Overall, it was discovered that hcp+C. coli and C. jejuni isolated from retail chicken isolates posses genetic and phenotypic properties associated with enhanced virulence. However, since human infections with C. coli are significantly less frequent than those of C. jejuni, the relationship between virulence factors and pathogenesis requires further study.
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Affiliation(s)
- Nicolae Corcionivoschi
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, BT9 5PX UK ; School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania, Calea Aradului nr. 119, Timisoara, Romania
| | - Ozan Gundogdu
- London School of Hygiene and Tropical Medicine, London, UK
| | - Lynn Moran
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, BT9 5PX UK
| | - Carmel Kelly
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, BT9 5PX UK
| | - Pam Scates
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, BT9 5PX UK
| | - Lavinia Stef
- School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania, Calea Aradului nr. 119, Timisoara, Romania
| | - Ada Cean
- School of Animal Science and Biotechnology, Banat University of Animal Sciences and Veterinary Medicine-King Michael I of Romania, Calea Aradului nr. 119, Timisoara, Romania
| | - Brendan Wren
- London School of Hygiene and Tropical Medicine, London, UK
| | - Nick Dorrell
- London School of Hygiene and Tropical Medicine, London, UK
| | - Robert H Madden
- Agri-Food and Biosciences Institute, Food Microbiology, Newforge Lane, Belfast, BT9 5PX UK
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14
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Gundogdu O, da Silva DT, Mohammad B, Elmi A, Mills DC, Wren BW, Dorrell N. The Campylobacter jejuni MarR-like transcriptional regulators RrpA and RrpB both influence bacterial responses to oxidative and aerobic stresses. Front Microbiol 2015; 6:724. [PMID: 26257713 PMCID: PMC4508579 DOI: 10.3389/fmicb.2015.00724] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/02/2015] [Indexed: 11/13/2022] Open
Abstract
The ability of the human intestinal pathogen Campylobacter jejuni to respond to oxidative stress is central to bacterial survival both in vivo during infection and in the environment. Re-annotation of the C. jejuni NCTC11168 genome revealed the presence of two MarR-type transcriptional regulators Cj1546 and Cj1556, originally annotated as hypothetical proteins, which we have designated RrpA and RrpB (regulator of response to peroxide) respectively. Previously we demonstrated a role for RrpB in both oxidative and aerobic (O2) stress and that RrpB was a DNA binding protein with auto-regulatory activity, typical of MarR-type transcriptional regulators. In this study, we show that RrpA is also a DNA binding protein and that a rrpA mutant in strain 11168H exhibits increased sensitivity to hydrogen peroxide oxidative stress. Mutation of either rrpA or rrpB reduces catalase (KatA) expression. However, a rrpAB double mutant exhibits higher levels of resistance to hydrogen peroxide oxidative stress, with levels of KatA expression similar to the wild-type strain. Mutation of either rrpA or rrpB also results in a reduction in the level of katA expression, but this reduction was not observed in the rrpAB double mutant. Neither the rrpA nor rrpB mutant exhibits any significant difference in sensitivity to either cumene hydroperoxide or menadione oxidative stresses, but both mutants exhibit a reduced ability to survive aerobic (O2) stress, enhanced biofilm formation and reduced virulence in the Galleria mellonella infection model. The rrpAB double mutant exhibits wild-type levels of biofilm formation and wild-type levels of virulence in the G mellonella infection model. Together these data indicate a role for both RrpA and RrpB in the C. jejuni peroxide oxidative and aerobic (O2) stress responses, enhancing bacterial survival in vivo and in the environment.
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Affiliation(s)
- Ozan Gundogdu
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
| | - Daiani T da Silva
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
| | - Banaz Mohammad
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
| | - Abdi Elmi
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
| | - Dominic C Mills
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
| | - Brendan W Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
| | - Nick Dorrell
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
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15
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Ugarte-Ruiz M, Stabler RA, Domínguez L, Porrero MC, Wren BW, Dorrell N, Gundogdu O. Prevalence of Type VI Secretion System in Spanish Campylobacter jejuni Isolates. Zoonoses Public Health 2014; 62:497-500. [PMID: 25496466 DOI: 10.1111/zph.12176] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Indexed: 11/27/2022]
Abstract
Infections from Campylobacter jejuni pose a serious public health problem and are now considered the leading cause of foodborne bacterial gastroenteritis throughout the world. Sequencing of C. jejuni genomes has previously allowed a number of loci to be identified, which encode virulence factors that aid survival and pathogenicity. Recently, a Type VI secretion system (T6SS) consisting of 13 conserved genes was described in C. jejuni strains and recognised to promote pathogenicity and adaptation to the environment. In this study, we determined the presence of this T6SS in 63 Spanish C. jejuni isolates from the food chain and urban effluents using whole-genome sequencing. Our findings demonstrated that nine (14%) strains harboured the 13 ORFs found in prototype strain C. jejuni 108. Further studies will be necessary to determine the prevalence and importance of T6SS-positive C. jejuni strains.
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Affiliation(s)
- M Ugarte-Ruiz
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain.,Departamento de Sanidad Animal, Facultad de Veterinaria. Universidad Complutense Madrid, Madrid, Spain
| | - R A Stabler
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - L Domínguez
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain
| | - M C Porrero
- VISAVET Health Surveillance Centre, Universidad Complutense Madrid, Madrid, Spain
| | - B W Wren
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - N Dorrell
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - O Gundogdu
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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16
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Stephenson HN, Mills DC, Jones H, Milioris E, Copland A, Dorrell N, Wren BW, Crocker PR, Escors D, Bajaj-Elliott M. Pseudaminic acid on Campylobacter jejuni flagella modulates dendritic cell IL-10 expression via Siglec-10 receptor: a novel flagellin-host interaction. J Infect Dis 2014; 210:1487-98. [PMID: 24823621 PMCID: PMC4195440 DOI: 10.1093/infdis/jiu287] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Introduction. Campylobacter jejuni is a leading cause of bacterial gastroenteritis worldwide. At present the identity of host-pathogen interactions that promote successful bacterial colonisation remain ill defined. Herein, we aimed to investigate C. jejuni-mediated effects on dendritic cell (DC) immunity. Results. We found C. jejuni to be a potent inducer of human and murine DC interleukin 10 (IL-10) in vitro, a cellular event that was MyD88- and p38 MAPK-signalling dependent. Utilizing a series of C. jejuni isogenic mutants we found the major flagellin protein, FlaA, modulated IL-10 expression, an intriguing observation as C. jejuni FlaA is not a TLR5 agonist. Further analysis revealed pseudaminic acid residues on the flagella contributed to DC IL-10 expression. We identified the ability of both viable C. jejuni and purified flagellum to bind to Siglec-10, an immune-modulatory receptor. In vitro infection of Siglec-10 overexpressing cells resulted in increased IL-10 expression in a p38-dependent manner. Detection of Siglec-10 on intestinal CD11c+ CD103+ DCs added further credence to the notion that this novel interaction may contribute to immune outcome during human infection. Conclusions. We propose that unlike the Salmonella Typhimurium flagella-TLR5 driven pro-inflammatory axis, C. jejuni flagella instead promote an anti-inflammatory axis via glycan-Siglec-10 engagement.
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Affiliation(s)
- Holly N Stephenson
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London
| | - Dominic C Mills
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine
| | - Hannah Jones
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London
| | - Enea Milioris
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London
| | - Alastair Copland
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London
| | - Nick Dorrell
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine
| | - Brendan W Wren
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine
| | | | - David Escors
- Rayne Institute, University College London, United Kingdom Navarrabiomed-Fundacion Miguel Servet, Pamplona, Navarra, Spain
| | - Mona Bajaj-Elliott
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London
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17
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Naz N, Mills DC, Wren BW, Dorrell N. Enteric bacterial invasion of intestinal epithelial cells in vitro is dramatically enhanced using a vertical diffusion chamber model. J Vis Exp 2013:e50741. [PMID: 24192850 DOI: 10.3791/50741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The interactions of bacterial pathogens with host cells have been investigated extensively using in vitro cell culture methods. However as such cell culture assays are performed under aerobic conditions, these in vitro models may not accurately represent the in vivo environment in which the host-pathogen interactions take place. We have developed an in vitro model of infection that permits the coculture of bacteria and host cells under different medium and gas conditions. The Vertical Diffusion Chamber (VDC) model mimics the conditions in the human intestine where bacteria will be under conditions of very low oxygen whilst tissue will be supplied with oxygen from the blood stream. Placing polarized intestinal epithelial cell (IEC) monolayers grown in Snapwell inserts into a VDC creates separate apical and basolateral compartments. The basolateral compartment is filled with cell culture medium, sealed and perfused with oxygen whilst the apical compartment is filled with broth, kept open and incubated under microaerobic conditions. Both Caco-2 and T84 IECs can be maintained in the VDC under these conditions without any apparent detrimental effects on cell survival or monolayer integrity. Coculturing experiments performed with different C. jejuni wild-type strains and different IEC lines in the VDC model with microaerobic conditions in the apical compartment reproducibly result in an increase in the number of interacting (almost 10-fold) and intracellular (almost 100-fold) bacteria compared to aerobic culture conditions. The environment created in the VDC model more closely mimics the environment encountered by C. jejuni in the human intestine and highlights the importance of performing in vitro infection assays under conditions that more closely mimic the in vivo reality. We propose that use of the VDC model will allow new interpretations of the interactions between bacterial pathogens and host cells.
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Affiliation(s)
- Neveda Naz
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine
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18
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Stephenson HN, John CM, Naz N, Gundogdu O, Dorrell N, Wren BW, Jarvis GA, Bajaj-Elliott M. Campylobacter jejuni lipooligosaccharide sialylation, phosphorylation, and amide/ester linkage modifications fine-tune human Toll-like receptor 4 activation. J Biol Chem 2013; 288:19661-72. [PMID: 23629657 DOI: 10.1074/jbc.m113.468298] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Campylobacter jejuni is a leading cause of acute gastroenteritis. C. jejuni lipooligosaccharide (LOS) is a potent activator of Toll-like receptor (TLR) 4-mediated innate immunity. Structural variations of the LOS have been previously reported in the oligosaccharide (OS) moiety, the disaccharide lipid A (LA) backbone, and the phosphorylation of the LA. Here, we studied LOS structural variation between C. jejuni strains associated with different ecological sources and analyzed their ability to activate TLR4 function. MALDI-TOF MS was performed to characterize structural variation in both the OS and LA among 15 different C. jejuni isolates. Cytokine induction in THP-1 cells and primary monocytes was correlated with LOS structural variation in each strain. Additionally, structural variation was correlated with the source of each strain. OS sialylation, increasing abundance of LA d-glucosamine versus 2,3-diamino-2,3-dideoxy-d-glucose, and phosphorylation status all correlated with TLR4 activation as measured in THP-1 cells and monocytes. Importantly, LOS-induced inflammatory responses were similar to those elicited by live bacteria, highlighting the prominent contribution of the LOS component in driving host immunity. OS sialylation status but not LA structure showed significant association with strains clustering with livestock sources. Our study highlights how variations in three structural components of C. jejuni LOS alter TLR4 activation and consequent monocyte activation.
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Affiliation(s)
- Holly N Stephenson
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, United Kingdom
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19
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Hepworth PJ, Ashelford KE, Hinds J, Gould KA, Witney AA, Williams NJ, Leatherbarrow H, French NP, Birtles RJ, Mendonca C, Dorrell N, Wren BW, Wigley P, Hall N, Winstanley C. Genomic variations define divergence of water/wildlife-associated Campylobacter jejuni niche specialists from common clonal complexes. Environ Microbiol 2011; 13:1549-60. [PMID: 21418497 PMCID: PMC3569610 DOI: 10.1111/j.1462-2920.2011.02461.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although the major food-borne pathogen Campylobacter jejuni has been isolated from diverse animal, human and environmental sources, our knowledge of genomic diversity in C. jejuni is based exclusively on human or human food-chain-associated isolates. Studies employing multilocus sequence typing have indicated that some clonal complexes are more commonly associated with particular sources. Using comparative genomic hybridization on a collection of 80 isolates representing diverse sources and clonal complexes, we identified a separate clade comprising a group of water/wildlife isolates of C. jejuni with multilocus sequence types uncharacteristic of human food-chain-associated isolates. By genome sequencing one representative of this diverse group (C. jejuni 1336), and a representative of the bank-vole niche specialist ST-3704 (C. jejuni 414), we identified deletions of genomic regions normally carried by human food-chain-associated C. jejuni. Several of the deleted regions included genes implicated in chicken colonization or in virulence. Novel genomic insertions contributing to the accessory genomes of strains 1336 and 414 were identified. Comparative analysis using PCR assays indicated that novel regions were common but not ubiquitous among the water/wildlife group of isolates, indicating further genomic diversity among this group, whereas all ST-3704 isolates carried the same novel accessory regions. While strain 1336 was able to colonize chicks, strain 414 was not, suggesting that regions specifically absent from the genome of strain 414 may play an important role in this common route of Campylobacter infection of humans. We suggest that the genomic divergence observed constitutes evidence of adaptation leading to niche specialization.
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Affiliation(s)
- Philip J Hepworth
- Institute of Infection and Global Health Institute of Integrative Biology National Centre for Zoonosis Research, University of Liverpool, Liverpool L69 3GA, UK
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20
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Edwards LA, Nistala K, Mills DC, Stephenson HN, Zilbauer M, Wren BW, Dorrell N, Lindley KJ, Wedderburn LR, Bajaj-Elliott M. Delineation of the innate and adaptive T-cell immune outcome in the human host in response to Campylobacter jejuni infection. PLoS One 2010; 5:e15398. [PMID: 21085698 PMCID: PMC2976761 DOI: 10.1371/journal.pone.0015398] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 09/04/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Campylobacter jejuni is the most prevalent cause of bacterial gastroenteritis worldwide. Despite the significant health burden this infection presents, molecular understanding of C. jejuni-mediated disease pathogenesis remains poorly defined. Here, we report the characterisation of the early, innate immune response to C. jejuni using an ex-vivo human gut model of infection. Secondly, impact of bacterial-driven dendritic cell activation on T-cell mediated immunity was also sought. METHODOLOGY Healthy, control paediatric terminal ileum or colonic biopsy tissue was infected with C. jejuni for 8-12 hours. Bacterial colonisation was followed by confocal microscopy and mucosal innate immune responses measured by ELISA. Marked induction of IFNγ with modest increase in IL-22 and IL-17A was noted. Increased mucosal IL-12, IL-23, IL-1β and IL-6 were indicative of a cytokine milieu that may modulate subsequent T-cell mediated immunity. C. jejuni-driven human monocyte-derived dendritic cell activation was followed by analyses of T cell immune responses utilising flow cytometry and ELISA. Significant increase in Th-17, Th-1 and Th-17/Th-1 double-positive cells and corresponding cytokines was observed. The ability of IFNγ, IL-22 and IL-17 cytokines to exert host defence via modulation of C. jejuni adhesion and invasion to intestinal epithelia was measured by standard gentamicin protection assay. CONCLUSIONS Both innate and adaptive T cell-immunity to C. jejuni infection led to the release of IFNγ, IL-22 and IL-17A; suggesting a critical role for this cytokine triad in establishing host anti-microbial immunity during the acute and effectors phase of infection. In addition, to their known anti-microbial functions; IL-17A and IL-17F reduced the number of intracellular C. jejuni in intestinal epithelia, highlighting a novel aspect of how IL-17 family members may contribute to protective immunity against C. jejuni.
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Affiliation(s)
- Lindsey A. Edwards
- Infectious Diseases and Microbiology, Institute of Child Health, London, United Kingdom
| | - Kiran Nistala
- Rheumatology, Institute of Child Health, London, United Kingdom
| | - Dominic C. Mills
- Pathogen Molecular Biology Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Holly N. Stephenson
- Infectious Diseases and Microbiology, Institute of Child Health, London, United Kingdom
| | - Matthias Zilbauer
- Infectious Diseases and Microbiology, Institute of Child Health, London, United Kingdom
- Paediatric Gastroenterology, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Brendan W. Wren
- Pathogen Molecular Biology Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Nick Dorrell
- Pathogen Molecular Biology Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Keith J. Lindley
- Autoimmunity and Surgery Units, Institute of Child Health, London, United Kingdom
| | | | - Mona Bajaj-Elliott
- Infectious Diseases and Microbiology, Institute of Child Health, London, United Kingdom
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Dorrell N, Champion OL, Wren BW. Microarray analysis of campylobacter jejuni: to the guts of the problem! Comp Funct Genomics 2008; 3:338-41. [PMID: 18629262 PMCID: PMC2448425 DOI: 10.1002/cfg.185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2002] [Accepted: 06/07/2002] [Indexed: 11/15/2022] Open
Affiliation(s)
- Nick Dorrell
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
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Kamal N, Dorrell N, Jagannathan A, Turner SM, Constantinidou C, Studholme DJ, Marsden G, Hinds J, Laing KG, Wren BW, Penn CW. Deletion of a previously uncharacterized flagellar-hook-length control gene fliK modulates the sigma54-dependent regulon in Campylobacter jejuni. Microbiology (Reading) 2007; 153:3099-3111. [PMID: 17768253 DOI: 10.1099/mic.0.2007/007401-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A previously unannotated, putative fliK gene was identified in the Campylobacter jejuni genome based on sequence analysis; deletion mutants in this gene had a 'polyhook' phenotype characteristic of fliK mutants in other genera. The mutants greatly overexpressed the sigma(54)-dependent flagellar hook protein FlgE, to form unusual filamentous structures resembling straight flagella in addition to polyhooks. The genome sequence reveals only one gene predicted to encode an orthologue of the NtrC-family activator required for sigma(54)-dependent transcription. Hence, all sigma(54)-dependent genes in the genome would be overexpressed in the fliK mutant together with flgE. Microarray analysis of genome-wide transcription in the mutant showed increased transcription of a subset of genes, often downstream of sigma(54)-dependent promoters identified by a quality-predictive algorithm applied to the whole genome. Assessment of genome-wide transcription in deletion mutants in rpoN, encoding sigma(54), and in the sigma(54)-activator gene flgR, showed reciprocally reduced transcription of genes that were overexpressed in the fliK mutant. The fliA (sigma(28))-dependent regulon was also analysed. Together the data clearly define the roles of the alternative sigma factors RpoN and FliA in flagellar biogenesis in C. jejuni, and identify additional putative members of their respective regulons.
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Affiliation(s)
- Nahid Kamal
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Nick Dorrell
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Aparna Jagannathan
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Susan M Turner
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | | | - Gemma Marsden
- Department of Medical Microbiology, St George's Hospital Medical School, Cranmer Terrace, Tooting, London SW17 0RE, UK
| | - Jason Hinds
- Department of Medical Microbiology, St George's Hospital Medical School, Cranmer Terrace, Tooting, London SW17 0RE, UK
| | - Ken G Laing
- Department of Medical Microbiology, St George's Hospital Medical School, Cranmer Terrace, Tooting, London SW17 0RE, UK
| | - Brendan W Wren
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Charles W Penn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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23
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Zilbauer M, Dorrell N, Elmi A, Lindley KJ, Schüller S, Jones HE, Klein NJ, Núňez G, Wren BW, Bajaj-Elliott M. A major role for intestinal epithelial nucleotide oligomerization domain 1 (NOD1) in eliciting host bactericidal immune responses to Campylobacter jejuni. Cell Microbiol 2007. [DOI: 10.1111/j.1462-5822.2007.01008.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
PURPOSE OF REVIEW Despite the prevalence of Campylobacter jejuni and the importance of the disease, investigations into pathogenesis have been restricted because of the absence of a convenient animal model of disease. In particular it is still unclear how C. jejuni infection causes diarrhoea. RECENT FINDINGS Recent developments in improved models of infection and studies on the innate immune responses have provided a deeper understanding of host-pathogen interactions. From the organism's perspective, further genomics-based information including two new genome sequences has provided much basic information, particularly relating to cell surface glycostructures. SUMMARY Research over the last few years is starting to address the gaps in our knowledge of how this important human pathogen interacts with host cells and causes diarrhoeal disease. Further research is required for a detailed understanding of these interactions and also to develop intervention strategies to reduce the burden of C. jejuni-associated disease.
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Affiliation(s)
- Nick Dorrell
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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25
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Zilbauer M, Dorrell N, Elmi A, Lindley KJ, Schüller S, Jones HE, Klein NJ, Núnez G, Wren BW, Bajaj-Elliott M. A major role for intestinal epithelial nucleotide oligomerization domain 1 (NOD1) in eliciting host bactericidal immune responses to Campylobacter jejuni. Cell Microbiol 2007; 9:2404-16. [PMID: 17521327 DOI: 10.1111/j.1462-5822.2007.00969.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Campylobacter jejuni is the foremost cause of bacterial-induced diarrhoeal disease worldwide. Although it is well established that C. jejuni infection of intestinal epithelia triggers host innate immune responses, the mechanism(s) involved remain poorly defined. Innate immunity can be initiated by families of structurally related pattern-recognition receptors (PRRs) that recognize specific microbial signature motifs. Here, we demonstrated maximal induction of epithelial innate responses during infection with live C. jejuni cells. In contrast when intestinal epithelial cells (IECs) were exposed to paraformaldehyde-fixed bacteria, host responses were minimal and a marked reduction in the number of intracellular bacteria was noted in parallel. These findings suggested a role for intracellular host-C. jejuni interactions in eliciting early innate immunity. We therefore investigated the potential involvement of a family of intracellular, cytoplasmic PRRs, the nucleotide-binding oligomerization domain (NOD) proteins in C. jejuni recognition. We identified NOD1, but not NOD2, as a major PRR for C. jejuni in IEC. We also found that targeting intestinal epithelial NOD1 with small interfering RNA resulted in an increase in number of intracellular C. jejuni, thus highlighting a critical role for NOD1-mediated antimicrobial defence mechanism(s) in combating this infection at the gastrointestinal mucosal surface.
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Affiliation(s)
- Matthias Zilbauer
- Infectious Diseases and Microbiology Unit, Institute of Child Health, 30 Guilford St, London WC1N 1EH, UK
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W. On SL, Dorrell N, Petersen L, Bang DD, Morris S, Forsythe SJ, Wren BW. Numerical analysis of DNA microarray data of Campylobacter jejuni strains correlated with survival, cytolethal distending toxin and haemolysin analyses. Int J Med Microbiol 2006; 296:353-63. [DOI: 10.1016/j.ijmm.2006.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 03/13/2006] [Accepted: 03/13/2006] [Indexed: 10/24/2022] Open
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Dorrell N, Hinchliffe SJ, Wren BW. Comparative phylogenomics of pathogenic bacteria by microarray analysis. Curr Opin Microbiol 2006; 8:620-6. [PMID: 16125441 PMCID: PMC7108221 DOI: 10.1016/j.mib.2005.08.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 08/15/2005] [Indexed: 10/31/2022]
Abstract
DNA microarrays represent a powerful technology that enables whole-scale comparison of bacterial genomes. This, coupled with new methods to model DNA microarray data, is facilitating the development of robust comparative phylogenomics analyses. Such studies have dramatically increased our ability to differentiate between bacteria, highlighting previously undetected genetic differences and population structures and providing new insight into virulence and evolution of bacterial pathogens. Recent results from such studies have generated insights into the evolution of bacterial pathogens, the levels of diversity and plasticity in the genome of a species, as well as the differences in virulence amongst pathogenic bacteria.
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Zilbauer M, Dorrell N, Boughan PK, Harris A, Wren BW, Klein NJ, Bajaj-Elliott M. Intestinal innate immunity to Campylobacter jejuni results in induction of bactericidal human beta-defensins 2 and 3. Infect Immun 2005; 73:7281-9. [PMID: 16239524 PMCID: PMC1273837 DOI: 10.1128/iai.73.11.7281-7289.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Campylobacter jejuni is the most prevalent cause of bacterial diarrhea worldwide. Despite the serious health problems caused by this bacterium, human innate immune responses to C. jejuni infection remain poorly defined. Human beta-defensins, a family of epithelial antimicrobial peptides, are a major component of host innate defense at the gastrointestinal mucosal surface. In this study, the effect of two different C. jejuni wild-type strains on human intestinal epithelial innate responses was investigated. Up-regulation of beta-defensin gene and peptide expression during infection was observed and recombinant beta-defensins were shown to have a direct bactericidal effect against C. jejuni through disruption of cell wall integrity. Further studies using an isogenic capsule-deficient mutant showed that, surprisingly, the absence of the bacterial polysaccharide capsule did not change the innate immune responses induced by C. jejuni or the ability of C. jejuni to survive exposure to recombinant beta-defensins. This study suggests a major role for this family of antimicrobial peptides in the innate immune defense against this human pathogen.
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Affiliation(s)
- Matthias Zilbauer
- Department of Infectious Diseases and Microbiology, Institute of Child Health, London WC1N 1EH, United Kingdom
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29
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Champion OL, Gaunt MW, Gundogdu O, Elmi A, Witney AA, Hinds J, Dorrell N, Wren BW. Comparative phylogenomics of the food-borne pathogen Campylobacter jejuni reveals genetic markers predictive of infection source. Proc Natl Acad Sci U S A 2005; 102:16043-8. [PMID: 16230626 PMCID: PMC1276044 DOI: 10.1073/pnas.0503252102] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Accepted: 09/12/2005] [Indexed: 12/19/2022] Open
Abstract
Campylobacter jejuni is the predominant cause of bacterial gastroenteritis worldwide, but traditional typing methods are unable to discriminate strains from different sources that cause disease in humans. We report the use of genomotyping (whole-genome comparisons of microbes using DNA microarrays) combined with Bayesian-based algorithms to model the phylogeny of this major food-borne pathogen. In this study 111 C. jejuni strains were examined by genomotyping isolates from humans with a spectrum of C. jejuni-associated disease (70 strains), chickens (17 strains), bovines (13 strains), ovines (5 strains), and the environment (6 strains). From these data, the Bayesian phylogeny of the isolates revealed two distinct clades unequivocally supported by Bayesian probabilities (P = 1); a livestock clade comprising 31/35 (88.6%) of the livestock isolates and a "nonlivestock" clade comprising further clades of environmental isolates. Several genes were identified as characteristic of strains in the livestock clade. The most prominent was a cluster of six genes (cj1321 to cj1326) within the flagellin glycosylation locus, which were confirmed by PCR analysis as genetic markers in six additional chicken-associated strains. Surprisingly these studies show that the majority (39/70, 55.7%) of C. jejuni human isolates were found in the nonlivestock clade, suggesting that most C. jejuni infections may be from nonlivestock (and possibly nonagricultural) sources. This study has provided insight into a previously unidentified reservoir of C. jejuni infection that may have implications in disease-control strategies. The comparative phylogenomics approach described provides a robust methodological prototype that should be applicable to other microbes.
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Affiliation(s)
- Olivia L Champion
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
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Woodall CA, Jones MA, Barrow PA, Hinds J, Marsden GL, Kelly DJ, Dorrell N, Wren BW, Maskell DJ. Campylobacter jejuni gene expression in the chick cecum: evidence for adaptation to a low-oxygen environment. Infect Immun 2005; 73:5278-85. [PMID: 16041056 PMCID: PMC1201244 DOI: 10.1128/iai.73.8.5278-5285.2005] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Transcriptional profiling of Campylobacter jejuni during colonization of the chick cecum identified 59 genes that were differentially expressed in vivo compared with the genes in vitro. The data suggest that C. jejuni regulates electron transport and central metabolic pathways to alter its physiological state during establishment in the chick cecum.
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Affiliation(s)
- C A Woodall
- Institute for Animal Health, Compton, Newbury, Berkshire RG20 7NN, United Kingdom
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31
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Linton D, Dorrell N, Hitchen PG, Amber S, Karlyshev AV, Morris HR, Dell A, Valvano MA, Aebi M, Wren BW. Functional analysis of the Campylobacter jejuni N-linked protein glycosylation pathway. Mol Microbiol 2005; 55:1695-703. [PMID: 15752194 DOI: 10.1111/j.1365-2958.2005.04519.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We describe in this report the characterization of the recently discovered N-linked glycosylation locus of the human bacterial pathogen Campylobacter jejuni, the first such system found in a species from the domain Bacteria. We exploited the ability of this locus to function in Escherichia coli to demonstrate through mutational and structural analyses that variant glycan structures can be transferred onto protein indicating the relaxed specificity of the putative oligosaccharyltransferase PglB. Structural data derived from these variant glycans allowed us to infer the role of five individual glycosyltransferases in the biosynthesis of the N-linked heptasaccharide. Furthermore, we show that C. jejuni- and E. coli-derived pathways can interact in the biosynthesis of N-linked glycoproteins. In particular, the E. coli encoded WecA protein, a UDP-GlcNAc: undecaprenylphosphate GlcNAc-1-phosphate transferase involved in glycolipid biosynthesis, provides for an alternative N-linked heptasaccharide biosynthetic pathway bypassing the requirement for the C. jejuni-derived glycosyltransferase PglC. This is the first experimental evidence that biosynthesis of the N-linked glycan occurs on a lipid-linked precursor prior to transfer onto protein. These findings provide a framework for understanding the process of N-linked protein glycosylation in Bacteria and for devising strategies to exploit this system for glycoengineering.
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Affiliation(s)
- Dennis Linton
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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32
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Moen B, Oust A, Langsrud Ø, Dorrell N, Marsden GL, Hinds J, Kohler A, Wren BW, Rudi K. Explorative multifactor approach for investigating global survival mechanisms of Campylobacter jejuni under environmental conditions. Appl Environ Microbiol 2005; 71:2086-94. [PMID: 15812042 PMCID: PMC1082531 DOI: 10.1128/aem.71.4.2086-2094.2005] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Explorative approaches such as DNA microarray experiments are becoming increasingly important in microbial research. Despite these major technical advancements, approaches to study multifactor experiments are still lacking. We have addressed this problem by using rotation testing and a novel multivariate analysis of variance (MANOVA) approach (50-50 MANOVA) to investigate interacting experimental factors in a complex experimental design. Furthermore, a new rotation testing based method was introduced to calculate false-discovery rates for each response. This novel analytical concept was used to investigate global survival mechanisms in the environment of the major food-borne pathogen C. jejuni. We simulated nongrowth environmental conditions by investigating combinations of the factors temperature (5 and 25 degrees C) and oxygen tension (anaerobic, microaerobic, and aerobic). Data were generated with DNA microarrays for information about gene expression patterns and Fourier transform infrared (FT-IR) spectroscopy to study global macromolecular changes in the cell. Microarray analyses showed that most genes were either unchanged or down regulated compared to the reference (day 0) for the conditions tested and that the 25 degrees C anaerobic condition gave the most distinct expression pattern with the fewest genes expressed. The few up-regulated genes were generally stress related and/or related to the cell envelope. We found, using FT-IR spectroscopy, that the amount of polysaccharides and oligosaccharides increased under the nongrowth survival conditions. Potential mechanisms for survival could be to down regulate most functions to save energy and to produce polysaccharides and oligosaccharides for protection against harsh environments. Basic knowledge about the survival mechanisms is of fundamental importance in preventing transmission of this bacterium through the food chain.
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Affiliation(s)
- Birgitte Moen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway.
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33
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Hatzifoti C, Bajaj-Elliott M, Dorrell N, Anyim M, Prentice MB, Nye KE, Wren B, Morrow WJW. A plasmid immunization construct encoding urease B of Helicobacter pylori induces an antigen-specific antibody response and upregulates the expression of beta-defensins and IL-10 in the stomachs of immunized mice. Vaccine 2004; 22:2651-9. [PMID: 15193391 DOI: 10.1016/j.vaccine.2003.11.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Accepted: 11/15/2003] [Indexed: 12/19/2022]
Abstract
The objectives of this study were to investigate the efficacy of a prototype DNA immunization construct encoding the urease B subunit enzyme of Helicobacter pylori (H. pylori) for inducing adaptive and innate immune responses in mice immunized via intramuscular or subcutaneous routes and to further explore the adjuvant effects of the CpG motifs in the vector. Antibody, cytokine, and beta-defensin profiles were assessed in the stomachs of immunized animals: experiments were terminated 3 months after immunization because there was a significant increase in the anti-H. pylori urease B antibody response at Week 6 in mice immunized with the urease B construct. A long lasting expression of IL-10 mRNA was noted. Furthermore, a marked and sustained increase in the mRNA expression of beta-defensins was also observed, particularly beta1. This study demonstrates that an H. pylori urease B DNA construct can induce innate as well as adaptive immune responses in the stomachs of immunized mice. Upregulation of beta-defensin gene expression followed immunization and we believe that this is the first report of a DNA vaccine inducing innate anti-microbial responses. Such complex molecular interactions that modulate both innate and adaptive immune responses may be of critical importance in the control of mucosal pathogens, such as H. pylori.
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Affiliation(s)
- Caterina Hatzifoti
- Departments of Immunology and Medical Microbiology, St Bartholomew's and the Royal London School of Medicine and Dentistry, London, UK
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Jones MA, Marston KL, Woodall CA, Maskell DJ, Linton D, Karlyshev AV, Dorrell N, Wren BW, Barrow PA. Adaptation of Campylobacter jejuni NCTC11168 to high-level colonization of the avian gastrointestinal tract. Infect Immun 2004; 72:3769-76. [PMID: 15213117 PMCID: PMC427441 DOI: 10.1128/iai.72.7.3769-3776.2004] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The genome sequence of the human pathogen Campylobacter jejuni NCTC11168 has been determined recently, but studies on colonization and persistence in chickens have been limited due to reports that this strain is a poor colonizer. Experimental colonization and persistence studies were carried out with C. jejuni NCTC11168 by using 2-week-old Light Sussex chickens possessing an acquired natural gut flora. After inoculation, NCTC11168 initially colonized the intestine poorly. However, after 5 weeks we observed adaptation to high-level colonization, which was maintained after in vitro passage. The adapted strain exhibited greatly increased motility. A second strain, C. jejuni 11168H, which had been selected under in vitro conditions for increased motility (A. V. Karlyshev, D. Linton, N. A. Gregson, and B. W. Wren, Microbiology 148:473-480, 2002), also showed high-level intestinal colonization. The levels of colonization were equivalent to those of six other strains, assessed under the same conditions. There were four mutations in C. jejuni 11168H that reduced colonization; maf5, flaA (motility and flagellation), and kpsM (capsule deficiency) eliminated colonization, whereas pglH (general glycosylation system deficient) reduced but did not eliminate colonization. This study showed that there was colonization of the avian intestinal tract by a Campylobacter strain having a known genome sequence, and it provides a model for colonization and persistence studies with specific mutations.
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Affiliation(s)
- Michael A Jones
- Institute for Animal Health, Compton, Newbury, Berkshire RG20 7NN, United Kingdom.
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35
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Zhang ZW, Dorrell N, Wren BW, Farthing MJG. Helicobacter pylori adherence to gastric epithelial cells: a role for non-adhesin virulence genes. J Med Microbiol 2002; 51:495-502. [PMID: 12018657 DOI: 10.1099/0022-1317-51-6-495] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Helicobacter pylori is a major aetiological agent in gastroduodenal disorders and adherence of the bacteria to the gastric mucosa is one of the initial stages of infection. Although a number of specific adhesins has been identified, other H. pylori virulence factors may play a role in adherence to gastric epithelial cells directly or through interaction with other adhesins. This study assessed the effect of 16 H. pylori virulence factors on the adherence of the bacteria to gastric AGS cells and on gastric epithelial cell cycle distribution. Defined isogenic H. pylori SS1 mutants were used. After co-incubation of gastric AGS cells and bacteria, adherence of H. pylori to AGS cells was visualised by immunofluorescence microscopy and quantified by flow cytometry. Cell cycle phase distribution was analysed by flow cytometry with propidium iodide staining. Mutants were tested for their ability to adhere to AGS cells and compared with the wild-type SS1 strain. Mutations in genes in the cag pathogenicity island showed that cagP and cagE mutants adhered less than the wild-type strain to AGS cells, whereas a cagF mutant showed no reduction in adherence. Mutations in genes involved in flagellar biosynthesis showed that the adherence ability of fliQ, fliM and fliS mutants was reduced, but a flhB mutant possessed wild-type levels of adherence. Mutations in genes coding for the urease (ureB) and phospholipase (pldA) enzymes did not affect adherence, but mutation of the tlyA gene encoding an H. pylori haemolysin resulted in a reduced adherence. A fliQ mutant, with reduced adherence to AGS cells, was less able to induce AGS cell apoptosis than SS1. The ability to induce G0G1 cell cycle arrest was also abolished in the fliQ mutant. However, an increased cell number in S phase was observed when AGS cells were exposed to the fliQ mutant compared with SS1, suggesting that unattached bacteria may still be able to stimulate cell proliferation. In addition to known adhesins, other bacterial virulence factors such as CagE, CagP, FliQ, FliM, FliS and TlyA appear to play a role in H. pylori adherence to gastric epithelial cells. Mutations in these genes may affect H. pylori pathogenicity by reducing either the ability of the bacteria to attach to gastric epithelial cells or the intensity of bacteria-host cell interactions.
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Affiliation(s)
| | - Nick Dorrell
- Division of Surgery, Bristol Royal Infirmary, University of Bristol, Bristol, *Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London and †Faculty of Medicine, University of Glasgow, Glasgow, UK
| | - Brendan W Wren
- Division of Surgery, Bristol Royal Infirmary, University of Bristol, Bristol, *Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London and †Faculty of Medicine, University of Glasgow, Glasgow, UK
| | - Michael J G Farthing
- Division of Surgery, Bristol Royal Infirmary, University of Bristol, Bristol, *Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London and †Faculty of Medicine, University of Glasgow, Glasgow, UK
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Dorrell N, Mangan JA, Laing KG, Hinds J, Linton D, Al-Ghusein H, Barrell BG, Parkhill J, Stoker NG, Karlyshev AV, Butcher PD, Wren BW. Whole genome comparison of Campylobacter jejuni human isolates using a low-cost microarray reveals extensive genetic diversity. Genome Res 2001; 11:1706-15. [PMID: 11591647 PMCID: PMC311159 DOI: 10.1101/gr.185801] [Citation(s) in RCA: 253] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Campylobacter jejuni is the leading cause of bacterial food-borne diarrhoeal disease throughout the world, and yet is still a poorly understood pathogen. Whole genome microarray comparisons of 11 C. jejuni strains of diverse origin identified genes in up to 30 NCTC 11168 loci ranging from 0.7 to 18.7 kb that are either absent or highly divergent in these isolates. Many of these regions are associated with the biosynthesis of surface structures including flagella, lipo-oligosaccharide, and the newly identified capsule. Other strain-variable genes of known function include those responsible for iron acquisition, DNA restriction/modification, and sialylation. In fact, at least 21% of genes in the sequenced strain appear dispensable as they are absent or highly divergent in one or more of the isolates tested, thus defining 1300 C. jejuni core genes. Such core genes contribute mainly to metabolic, biosynthetic, cellular, and regulatory processes, but many virulence determinants are also conserved. Comparison of the capsule biosynthesis locus revealed conservation of all the genes in this region in strains with the same Penner serotype as strain NCTC 11168. By contrast, between 5 and 17 NCTC 11168 genes in this region are either absent or highly divergent in strains of a different serotype from the sequenced strain, providing further evidence that the capsule accounts for Penner serotype specificity. These studies reveal extensive genetic diversity among C. jejuni strains and pave the way toward identifying correlates of pathogenicity and developing improved epidemiological tools for this problematic pathogen.
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Affiliation(s)
- N Dorrell
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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Affiliation(s)
- B W Wren
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
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Martino MC, Stabler RA, Zhang ZW, Farthing MJ, Wren BW, Dorrell N. Helicobacter pylori pore-forming cytolysin orthologue TlyA possesses in vitro hemolytic activity and has a role in colonization of the gastric mucosa. Infect Immun 2001; 69:1697-703. [PMID: 11179345 PMCID: PMC98074 DOI: 10.1128/iai.69.3.1697-1703.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Hemolysins have been found to possess a variety of functions in bacteria, including a role in virulence. Helicobacter pylori demonstrates hemolytic activity when cultured on unlysed blood agar plates which is increased under iron-limiting conditions. However, the role of an H. pylori hemolysin in virulence is unclear. Scrutiny of the H. pylori 26695 genome sequence suggests the presence of at least two distinct hemolysins, HP1086 and HP1490, in this strain. Previous studies have shown that the in vitro hemolytic activity of H. pylori is reduced when it is coincubated with dextran 5000, suggesting the presence of a pore-forming cytolysin. HP1086 has homology to pore-forming cytolysins (TlyA) from other bacterial species, and the introduction of the cloned H. pylori tlyA gene into a nonhemolytic Escherichia coli strain conferred hemolytic activity. An H. pylori tlyA defined mutant showed reduced in vitro hemolytic activity, which appears to be due to pore formation, as the hemolytic activity of the wild-type strain is reduced to the same level as the tlyA mutant by the addition of dextran 5000. The mutant also showed reduced adhesion to human gastric adenocarcinoma cells and failed to colonize the gastric mucosa of mice. These data clearly suggest a role in virulence for H. pylori TlyA, contrary to the suggestion that hemolytic activity is an in vitro phenomenon for this pathogen.
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Affiliation(s)
- M C Martino
- Pathogen Molecular Biology and Biochemistry Unit, Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Allan E, Dorrell N, Foynes S, Anyim M, Wren BW. Mutational analysis of genes encoding the early flagellar components of Helicobacter pylori: evidence for transcriptional regulation of flagellin A biosynthesis. J Bacteriol 2000; 182:5274-7. [PMID: 10960117 PMCID: PMC94681 DOI: 10.1128/jb.182.18.5274-5277.2000] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We investigated the roles of fliF, fliS, flhB, fliQ, fliG, and fliI of Helicobacter pylori, predicted by homology to encode structural components of the flagellar basal body and export apparatus. Mutation of these genes resulted in nonmotile, nonflagellate strains. Western blot analysis showed that all the mutants had considerably reduced levels of both flagellin subunits and of FlgE, the flagellar hook protein. RNA slot blot hybridization showed reduced levels of flaA mRNA, indicating that transcription of the major flagellin gene is inhibited in the absence of the early components of the flagellar-assembly pathway. This is the first demonstration of a checkpoint in H. pylori flagellar assembly.
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Affiliation(s)
- E Allan
- Pathogen Molecular Biology and Biochemistry Unit, Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, United Kingdom
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Oyston PC, Dorrell N, Williams K, Li SR, Green M, Titball RW, Wren BW. The response regulator PhoP is important for survival under conditions of macrophage-induced stress and virulence in Yersinia pestis. Infect Immun 2000; 68:3419-25. [PMID: 10816493 PMCID: PMC97616 DOI: 10.1128/iai.68.6.3419-3425.2000] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The two-component regulatory system PhoPQ has been identified in many bacterial species. However, the role of PhoPQ in regulating virulence gene expression in pathogenic bacteria has been characterized only in Salmonella species. We have identified, cloned, and sequenced PhoP orthologues from Yersinia pestis, Yersinia pseudotuberculosis, and Yersinia enterocolitica. To investigate the role of PhoP in the pathogenicity of Y. pestis, an isogenic phoP mutant was constructed by using a reverse-genetics PCR-based strategy. The protein profiles of the wild-type and phoP mutant strains, grown at either 28 or 37 degrees C, revealed more than 20 differences, indicating that PhoP has pleiotrophic effects on gene expression in Y. pestis. The mutant showed a reduced ability to survive in J774 macrophage cell cultures and under conditions of low pH and oxidative stress in vitro. The mean lethal dose of the phoP mutant in mice was increased 75-fold in comparison with that of the wild-type strain, indicating that the PhoPQ system plays a key role in regulating the virulence of Y. pestis.
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Affiliation(s)
- P C Oyston
- Defence Evaluation and Research Agency, Salisbury, Wiltshire, SP4 0JQ, United Kingdom
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Williams K, Oyston PC, Dorrell N, Li S, Titball RW, Wren BW. Investigation into the role of the serine protease HtrA in Yersinia pestis pathogenesis. FEMS Microbiol Lett 2000; 186:281-6. [PMID: 10802185 DOI: 10.1111/j.1574-6968.2000.tb09118.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The HtrA stress response protein has been shown to play a role in the virulence of a number of pathogens. For some organisms, htrA mutants are attenuated in the animal model and can be used as live vaccines. A Yersinia pestis htrA orthologue was identified, cloned and sequenced, showing 86% and 87% similarity to Escherichia coli and Salmonella typhimurium HtrAs. An isogenic Y. pestis htrA mutant was constructed using a reverse genetics approach. In contrast to the wild-type strain, the mutant failed to grow at an elevated temperature of 39 degrees C, but showed only a small increase in sensitivity to oxidative stress and was only partially attenuated in the animal model. However, the mutant exhibited a different protein expression profile to that of the wild-type strain when grown at 28 degrees C to simulate growth in the flea.
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Affiliation(s)
- K Williams
- Pathogen Molecular Biology and Biochemistry Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
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Foynes S, Dorrell N, Ward SJ, Stabler RA, McColm AA, Rycroft AN, Wren BW. Helicobacter pylori possesses two CheY response regulators and a histidine kinase sensor, CheA, which are essential for chemotaxis and colonization of the gastric mucosa. Infect Immun 2000; 68:2016-23. [PMID: 10722597 PMCID: PMC97381 DOI: 10.1128/iai.68.4.2016-2023.2000] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection of the mucous layer of the human stomach by Helicobacter pylori requires the bacterium to be motile and presumably chemotactic. Previous studies have shown that fully functional flagella are essential for motility and colonization, but the role of chemotaxis remains unclear. The two-component regulatory system CheA/CheY has been shown to play a major role in chemotaxis in other enteric bacteria. Scrutiny of the 26695 genome sequence suggests that H. pylori has two CheY response regulators: one a separate protein (CheY1) and the other (CheY2) fused to the histidine kinase sensor CheA. Defined deletion mutations were introduced into cheY1, cheY2, and cheA in H. pylori strains N6 and SS1. Video tracking revealed that the wild-type H. pylori strain moves in short runs with frequent direction changes, in contrast to movement of cheY2, cheAY2, and cheAY2 cheY1 mutants, whose motion was more linear. The cheY1 mutant demonstrated a different motility phenotype of rapid tumbling. All mutants had impaired swarming and greatly reduced chemotactic responses to hog gastric mucin. Neither cheY1 nor cheAY2 mutants were able to colonize mice, but they generated a significant antibody response, suggesting that despite impaired chemotaxis, these mutants were able to survive in the stomach long enough to induce an immune response before being removed by gastric flow. Additionally, we demonstrated that cheY1 failed to colonize gnotobiotic piglets. This study demonstrates the importance of the roles of cheY1, cheY2, and cheA in motility and virulence of H. pylori.
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Affiliation(s)
- S Foynes
- Pathogen Molecular Biology and Biochemistry Unit, Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Dorrell N, Martino MC, Stabler RA, Ward SJ, Zhang ZW, McColm AA, Farthing MJ, Wren BW. Characterization of Helicobacter pylori PldA, a phospholipase with a role in colonization of the gastric mucosa. Gastroenterology 1999; 117:1098-104. [PMID: 10535872 DOI: 10.1016/s0016-5085(99)70394-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND & AIMS Phospholipase activity may play a role in the pathogenicity of Helicobacter pylori. Furthermore, some drugs that are effective against H. pylori infection are phospholipase inhibitors. Scrutiny of the H. pylori 26695 genome sequence revealed the presence of a putative protein with homology to Esherichia coli outer membrane phospholipase A (PldA). The aim of this study was to investigate the role of this putative PldA in the pathogenicity of H. pylori. METHODS An isogenic pldA mutant was constructed and analyzed for in vitro phospholipase A(2) and hemolytic activity. Adherence of the mutant to human gastric adenocarcinoma cells and the ability to colonize mice were also investigated. RESULTS The pldA mutant showed a marked reduction in phospholipase A(2) and hemolytic activity compared with the wild-type strain. The mutant was unable to colonize mice at 2 and 8 weeks, but it did induce a significant immune response. In contrast, the ability of the mutant to adhere to human gastric adenocarcinoma cells was unaffected. CONCLUSIONS The results suggest a role for PldA in colonization of the gastric mucosa and possibly tissue damage after colonization.
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Affiliation(s)
- N Dorrell
- Pathogen Molecular Biology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, England
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Dorrell N, Guigue-Talet P, Spencer S, Foulonge V, O'Callaghan D, Wren BW. Investigation into the role of the response regulator NtrC in the metabolism and virulence of Brucella suis. Microb Pathog 1999; 27:1-11. [PMID: 10373105 DOI: 10.1006/mpat.1999.0278] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During infection, Brucella species have to adapt to a range of different environments. Environmental sensing in bacteria often involves the concerted action of two-component regulatory systems consisting of sensor and response regulator components. In this study, we identified, cloned and sequenced four independent response regulator gene fragments from Brucella melitensis. One amplified gene fragment showed nearly 90% identity to the response regulator subfamily of NtrC transcriptional activators, and further analysis revealed the presence of an adjacent gene encoding the sensor protein NtrB. The NtrBC two-component regulatory system has been shown to play varying roles in nitrogen metabolism and potentially in virulence in other bacterial species. A B. suis ntrC isogenic mutant was constructed which showed no significant differences in growth rates compared to the wild-type strain when grown at different temperatures in vitro. However, the mutant exhibited a reduction in metabolic activity in the presence of many amino acids. The mutation did not affect survival or multiplication of B. suis in macrophages, but during the initial stages of infection in the murine brucellosis model, the ntrC mutant showed a reduced ability to multiply rapidly in splenic tissue.
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Affiliation(s)
- N Dorrell
- Department of Medical Microbiology, St. Bartholomew's and the Royal London School of Medicine and Dentistry, West Smithfield, London, UK
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Foynes S, Dorrell N, Ward SJ, Zhang ZW, McColm AA, Farthing MJ, Wren BW. Functional analysis of the roles of FliQ and FlhB in flagellar expression in Helicobacter pylori. FEMS Microbiol Lett 1999; 174:33-9. [PMID: 10234819 DOI: 10.1111/j.1574-6968.1999.tb13546.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Expression of the two Helicobacter pylori flagellin proteins FlaA and FlaB is required for full motility and persistent infection of the gastric mucosa. The mechanisms and regulation of the biosynthesis and export of flagella in H. pylori are still poorly understood. Scrutiny of the H. pylori 26695 genome sequence revealed homologues of FliQ and FlhB. The roles of the fliQ and flhB genes in H. pylori were investigated by the construction and characterisation of defined isogenic mutants. The results indicate that these genes are involved in the flagellar expression, adhesion to and colonisation of the gastric mucosa.
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Affiliation(s)
- S Foynes
- Department of Medical Microbiology, St. Bartholomew's, West Smithfield, London, UK
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Allan E, Foynes S, Dorrell N, Wren B. 11 Genetic Characterization of the Gastric Pathogen Helicobacter pylori. J Microbiol Methods 1999. [DOI: 10.1016/s0580-9517(08)70122-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Affiliation(s)
- N Dorrell
- Dept of Medical Microbiology, St Bartholomew's, West Smithfield, London, UK.
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Abstract
The ompR-envZ two-component regulatory system has been shown to contribute to virulence in a number of enteric bacterial pathogens. A Yersinia enterocolitica O:8 ompR homologue was amplified, cloned and sequenced, showing 99.2% homology to the Escherichia coli OmpR. An isogenic ompR mutant was constructed by reverse genetics-based methodology. The mutant was shown to have increased sensitivity to high osmolarity, high temperature and low pH stresses in vitro. In the murine yersiniosis model, the mutant was attenuated and offered partial protection against wild-type challenge.
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Affiliation(s)
- N Dorrell
- Department of Medical Microbiology, St. Bartholomew's and the Royal London School of Medicine and Dentistry, London, UK
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Dorrell N, Spencer S, Foulonge V, Guigue-Talet P, O'Callaghan D, Wren BW. Identification, cloning and initial characterisation of FeuPQ in Brucella suis: a new sub-family of two-component regulatory systems. FEMS Microbiol Lett 1998; 162:143-50. [PMID: 9595675 DOI: 10.1111/j.1574-6968.1998.tb12991.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
To cause disease, Brucella species have to adapt to a range of different environments. Environmental sensing and adaptive responses in bacteria often involve the concerted action of a two-component regulatory system, consisting of sensor and response regulator components. Amplification and sequence analysis of response regulators from Brucella species identified a response regulator sequence with 96% similarity to Rhizobium leguminosarum FeuP. In R. leguminosarum, the FeuPQ two-component system is involved in the regulation of iron uptake. A Brucella suis feuP isogenic mutant was constructed but was not attenuated in the murine brucellosis model. The survival and multiplication of the mutant in macrophages was also unaffected. The FeuPQ regulon represents a newly characterised sub-family of response regulators.
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Affiliation(s)
- N Dorrell
- Department of Medical Microbiology, St. Bartholomew's, London, UK.
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Affiliation(s)
- N Dorrell
- Department of Medical Microbiology, St Bartholomew's, West Smithfield, London, UK
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