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Pereira CER, Resende TP, Daniel AGDS, Vannucci FA, Gebhart C, Guedes RMC. Evaluation of the role of clathrin and bacterial viability in the endocytosis of Lawsonia intracellularis. Front Vet Sci 2023; 10:1005676. [PMID: 36793380 PMCID: PMC9923121 DOI: 10.3389/fvets.2023.1005676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 01/10/2023] [Indexed: 01/31/2023] Open
Abstract
Lawsonia intracellularis is an obligate intracellular bacterium and causative agent of proliferative enteropathy. The pathogenesis of L. intracellularis is not completely understood, including the endocytic mechanisms to access the host cell cytoplasm. In this study, we evaluated the mechanisms involved in endocytosis of L. intracellularis in vitro using intestinal porcine epithelial cells (IPEC-J2). Confocal microscopy was used to co-localize L. intracellularis and clathrin. Clathrin gene knockdown was then applied to verify whether L. intracellularis endocytosis is clathrin-dependent. Finally, internalization of viable and non-viable (bacteria were inactivated by heat) L. intracellularis organisms were assessed to study the role of the host cell during bacterial endocytosis. L. intracellularis organisms were observed co-localized with clathrin by confocal microscopy but the amount of L. intracellularis internalized in cells, with and without clathrin knockdown, did not differ statistically. The internalization of non-viable L. intracellularis showed a decrease in the internalization in cells with less clathrin synthesis (P<0.05). The present study is the first to elucidate the involvement of clathrin in the endocytosis of L. intracellularis. Clathrin-mediated endocytosis was shown to be an important, but not required, process for L. intracellularis internalization in porcine intestinal epithelial cells. Independence of bacterial viability for host cell internalization was also confirmed.
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Affiliation(s)
- Carlos Eduardo Real Pereira
- Department of Clinic and Surgery, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil,Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Amanda Gabrielle de Souza Daniel
- Department of Clinic and Surgery, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil,Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Fabio Augusto Vannucci
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Connie Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Roberto Mauricio Carvalho Guedes
- Department of Clinic and Surgery, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil,*Correspondence: Roberto Mauricio Carvalho Guedes ✉
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2
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Xiao N, Li J, Li M, Zhou H, Lin H, Fan H. Isolation and In Vitro cultivation of Lawsonia intracellularis from China. Vet Microbiol 2022; 270:109457. [PMID: 35609389 DOI: 10.1016/j.vetmic.2022.109457] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 04/02/2022] [Accepted: 05/09/2022] [Indexed: 11/20/2022]
Abstract
Lawsonia intracellularis is an obligate intracellular bacterium that cannot be cultured by conventional bacteriological methods. Pigs infected with L. intracellularis suffer from decreased daily weight gain and poor feed conversion ratio. China is a large producer of pigs, but epidemiological investigation data of L. intracellularis has not been obtained in recent years. Additionally, there is no information about a L. intracellularis strain being successfully isolated and established in cell culture in China, and the above shortcomings limit understanding of the pathogenesis of L. intracellularis and alternative prevention and control methods. The aims of this study were to estimate the seroprevalence of L. intracellularis antibodies in eight major pig-producing provinces in China during 2019-2020, to isolate L. intracellularis from infected intestines and then to establish an infection model of L. intracellularis in mice. Our results showed that of the 3586 serum samples, 2837 (79.1%, 95% CI: 77.7%, 80.4%) were seropositive for the L. intracellularis antibody. Subsequently, the L. intracellularis strain LJS19051 from China was successfully isolated and established in cell culture. Furthermore, L. intracellularis DNA and antibodies could be detected in the feces and serum samples of infected mice, respectively. Moreover, infected crypts showed typical proliferative enteropathies (PE) lesions and L. intracellularis antigen was detected in infected mice by immunofluorescence at 28 days post inoculation. The results indicated that the new L. intracellularis strain LJS19051 was obtained and could successfully proliferate in ICR mice.
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Affiliation(s)
- Ning Xiao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Jiannan Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Minxue Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Hong Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
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3
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Li M, Xiao N, Li J, Lin H, Fan H. Evaluation of immune efficacy of Omp2 protein against Lawsonia intracellularis in mice. Vet Microbiol 2021; 263:109274. [PMID: 34781192 DOI: 10.1016/j.vetmic.2021.109274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 08/31/2021] [Accepted: 10/29/2021] [Indexed: 11/16/2022]
Abstract
Porcine proliferative enteropathy (PPE) is caused by the obligate intracellular bacterium Lawsonia intracellularis. Infection results in an enteric disease characterised by decreased growth performance of pigs, and presents a major economic burden for swine industries worldwide. Since vaccination is an effective technique for controlling PPE, novel effective vaccine platforms are need to be developed. In this study, five proteins of L. intracellularis were screened through animal experiments and the highly immunoprotective Omp2 protein was identified. Then, the immune efficacy of Omp2 was further evaluated based on humoral and cell mediated immune (CMI) responses, faecal bacterial shedding, histopathological lesions, immune barrier function of intestinal mucosa as well as digestive and absorptive capacity following challenge of mice with L. intracellularis. Mice immunised with Omp2 had reduced faecal shedding, fewer histopathological lesions and reduced bacteria colonisation of the ileum. Additionally, Omp2 immunised mice showed stronger serum IgG and IFN-γ levels, up-regulated Occludin and zonula occludens-1 (ZO-1) mRNA levels, as well as increased numbers of intestinal intraepithelial lymphocytes (IELs) and levels of sIgA. On the contrary, the activities of LPS, α-AMS and AKP were significantly increased. Our investigation indicated that immunization with Omp2 reduced the severity of clinical signs and provided efficacious immunoprotection for target animals against L. intracellularis infection in mouse model.
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Affiliation(s)
- Minxue Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ning Xiao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiannan Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
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4
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Campillo M, Smith SH, Gally DL, Opriessnig T. Review of methods for the detection of Lawsonia intracellularis infection in pigs. J Vet Diagn Invest 2021; 33:621-631. [PMID: 33739176 PMCID: PMC8225690 DOI: 10.1177/10406387211003551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Lawsonia intracellularis is an obligate intracellular bacterium
associated with enteric disease in pigs. Clinical signs include weight loss,
diarrhea, and, in some cases, sudden death. The hallmark lesion is the
thickening of the intestinal mucosa caused by increased epithelial cell
replication, known as proliferative enteropathy. The immune response to
L. intracellularis is not well defined, and detection of
the infection, especially in the early stages, is still a significant challenge.
We review here the main approaches used to identify this important but poorly
understood pathogen. Detection of L. intracellularis infection
as the cause of clinical disease is confounded by the high prevalence of the
pathogen in many countries and that several other pathogens can produce similar
clinical signs. A single L. intracellularis–specific ELISA and
several amplification assays are available commercially to aid detection and
surveillance, although histopathology remains the primary way to reach a
conclusive diagnosis. There are major gaps in our understanding of L.
intracellularis pathogenesis, especially how the host responds to
infection and the factors that drive infection toward different clinical
outcomes. Knowledge of pathogenesis will increase the predictive value of
antemortem tests to guide appropriate interventions, including identification
and treatment of subclinically affected pigs in the early stages of disease,
given that this important manifestation reduces pig productivity and contributes
to the economic burden of L. intracellularis worldwide.
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Affiliation(s)
- Marta Campillo
- The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Sionagh H Smith
- The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - David L Gally
- The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Tanja Opriessnig
- The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
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Muwonge A, Karuppannan AK, Opriessnig T. Probiotics mediated gut microbiota diversity shifts are associated with reduction in histopathology and shedding of Lawsonia intracellularis. Anim Microbiome 2021; 3:22. [PMID: 33663618 PMCID: PMC7931366 DOI: 10.1186/s42523-021-00084-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 02/11/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Clinical intervention during bacterial infections in farm animals such as pigs commonly includes the use of antimicrobials. With the rise of antimicrobial resistance and the attempts to reduce the use of antibiotics in food animals, effective alternatives are urgently needed to reduce or even remove pathogens and disease risks. Improving clinical outcomes and overall pig health by using probiotics appears attractive. However, reliable data sets on the efficacy of probiotics are scarce. The obligate intracellular bacterium Lawsonia intracellularis is widespread in pigs and associated with severe enteropathy, mainly in the ileum, commonly resulting in substantial reduction in weight gain. The impact of three in-feed probiotics and a commercial live L. intracellularis vaccine was compared in a pig challenge model. Probiotic treatment was associated with reduced L. intracellularis fecal shedding and reduced gut lesions. Here, the bacterial microbiota of the ileum of these pigs was characterized with 16S rRNA gene sequencing and was subsequently analyzed with bioinformatics tools. RESULTS The greatest microbial richness was observed in the probiotic treated group T03-LAW, which accounted for 87% of richness observed in the study. Treatment had a significant impact on both the microbiota structure and taxonomic profile in the ileum, explaining between 26 and 36% of the structural variation, with the strongest association in the T03-LAW group. Overall, the largest changes were observed for the pigs treated with in-feed Bacillus pumilus; the microbiota of these pigs had the greatest diversity and highest richness. We also observed depleted and enriched core microbiota amongst the groups; however, there was no correlation with clinical characteristics. The results suggest that an increased diversity of the ileal microbiota is associated with a reduction in shedding, i.e. a unit increase in Shannon diversity index resulted in 2.8 log reduction in shedding. CONCLUSIONS Probiotic supplementation of a base feed ration increased ileum microbiota diversity leading to a mitigation of the effects of a pathogenic L. intracellularis challenge. An even and diverse microbiota community benefits pigs infected with L. intracellularis, however, investigations are needed to determine if this is also true for other pathogens. The study unambiguously demonstrates the usefulness of probiotic supplementation in reducing the impact of enteric pathogens and pathogen shedding rates in food animals without the use of antimicrobials.
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Affiliation(s)
- Adrian Muwonge
- The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - Anbu K Karuppannan
- Vaccine Research Centre-Viral Vaccines, Centre for Animal Health Studies, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
| | - Tanja Opriessnig
- The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK.
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
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6
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Salazar S, Gutiérrez N, Sánchez O, Ramos E, González A, Acosta J, Ramos T, Altamirano C, Toledo J, Montesino R. Establishment of a production process for a novel vaccine candidate against Lawsonia intracellularis. ELECTRON J BIOTECHN 2021. [DOI: 10.1016/j.ejbt.2021.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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7
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Pereira CER, Resende TP, Armién AG, Laub RP, Vannucci FA, Santos RL, Gebhart CJ, Guedes RMC. Survival of Lawsonia intracellularis in porcine peripheral blood monocyte-derived macrophages. PLoS One 2020; 15:e0236887. [PMID: 32735621 PMCID: PMC7394435 DOI: 10.1371/journal.pone.0236887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/15/2020] [Indexed: 11/18/2022] Open
Abstract
Lawsonia intracellularis, an obligately intracellular enteric bacterium, infects intestinal epithelial cells, but may also be found within macrophages in the intestinal lamina propria of affected pigs. Macrophages play an important role in host defense against infectious agents, but the role of this cell in L. intracellularis infection is not well understood. The aim of this study was to evaluate the permissibility of macrophages to L. intracellularis infection in vitro. Pure culture of L. intracellularis was added to swine peripheral blood monocyte-derived macrophages. Viability of intracytoplasmic L. intracellularis was evaluated at different time points by transmission electron microscopy (TEM). Potential replication of L. intracellularis in macrophages was also evaluated by qPCR. By TEM, phagocytosis L. intracellularis within of phagolysosomes were observed 1-hour post-infection (hpi) and bacterial structures in binary fission at 48 hpi. The number of intracellular bacteria was determined at 1, 4, 24, 48, and 72 hpi by qPCR in infected macrophages and compared to the number of intracellular bacteria from culture in McCoy cells. In both cell lines, the amount of L. intracellularis was decreased at 4 hpiand increased at 24 hpi. The number of intracellular bacteria continued to increase in McCoy cells over time. This is the first study showing interaction, survival and propagation of L. intracellularis in macrophages. These findings are critical to establish an experimental model for future studies of the pathogenesis of porcine proliferative enteropathy and the potential persistence of L. intracellularis in macrophages during chronic infections.
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Affiliation(s)
- Carlos Eduardo Real Pereira
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Aníbal G. Armién
- Department of Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- Ultrastructural Pathology Unit, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Ricardo Pereira Laub
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Fabio Augusto Vannucci
- Department of Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Renato Lima Santos
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Connie Jane Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- Department of Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Roberto Mauricio Carvalho Guedes
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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8
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Resende TP, Medida RL, Vannucci FA, Saqui-Salces M, Gebhart C. Evaluation of swine enteroids as in vitro models for Lawsonia intracellularis infection1,2. J Anim Sci 2020; 98:5707101. [PMID: 31943029 PMCID: PMC7007770 DOI: 10.1093/jas/skaa011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/13/2020] [Indexed: 12/17/2022] Open
Abstract
The enteric pathogen Lawsonia intracellularis is one of the main causes of diarrhea and compromised weight gain in pigs worldwide. Traditional cell-line cultures have been used to study L. intracellularis pathogenesis. However, these systems fail to reproduce the epithelial changes observed in the intestines of L. intracellularis-infected pigs, specifically, the changes in intestinal cell constitution and gene expression. A more physiologically accurate and state-of-the-art model is provided by swine enteroids derived from stem cell-containing crypts from healthy pigs. The objective of this study was to verify the feasibility of two-dimensional swine enteroids as in vitro models for L. intracellularis infection. We established both three- and two-dimensional swine enteroid cultures derived from intestinal crypts. The two-dimensional swine enteroids were infected by L. intracellularis in four independent experiments. Enteroid-infected samples were collected 3 and 7 d postinfection for analysis using real-time quantitative PCR and L. intracellularis immunohistochemistry. In this study, we show that L. intracellularis is capable of infecting and replicating intracellularly in two-dimensional swine enteroids derived from ileum.
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Affiliation(s)
- Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN
| | - Ramya Lekha Medida
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN
| | - Fabio A Vannucci
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN
| | - Milena Saqui-Salces
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN
| | - Connie Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN.,Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN
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Bengtsson RJ, Wee BA, Yebra G, Bacigalupe R, Watson E, Guedes RMC, Jacobson M, Stadejek T, Archibald AL, Fitzgerald JR, Ait-Ali T. Metagenomic sequencing of clinical samples reveals a single widespread clone of Lawsonia intracellularis responsible for porcine proliferative enteropathy. Microb Genom 2020; 6:e000358. [PMID: 32238228 PMCID: PMC7276710 DOI: 10.1099/mgen.0.000358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 03/09/2020] [Indexed: 11/18/2022] Open
Abstract
Lawsonia intracellularis is a Gram-negative obligate intracellular bacterium that is the aetiological agent of proliferative enteropathy (PE), a common intestinal disease of major economic importance in pigs and other animal species. To date, progress in understanding the biology of L. intracellularis for improved disease control has been hampered by the inability to culture the organism in vitro. In particular, our understanding of the genomic diversity and population structure of clinical L. intercellularis is very limited. Here, we utilized a metagenomic shotgun approach to directly sequence and assemble 21 L. intracellularis genomes from faecal and ileum samples of infected pigs and horses across three continents. Phylogenetic analysis revealed a genetically monomorphic clonal lineage responsible for infections in pigs, with distinct subtypes associated with infections in horses. The genome was highly conserved, with 94 % of genes shared by all isolates and a very small accessory genome made up of only 84 genes across all sequenced strains. In part, the accessory genome was represented by regions with a high density of SNPs, indicative of recombination events importing novel gene alleles. In summary, our analysis provides the first view of the population structure for L. intracellularis, revealing a single major lineage associated with disease of pigs. The limited diversity and broad geographical distribution suggest the recent emergence and clonal expansion of an important livestock pathogen.
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Affiliation(s)
- Rebecca J. Bengtsson
- Department of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh, UK
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Bryan A. Wee
- Department of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh, UK
- Usher Institute, University of Edinburgh, Edinburgh, UK
| | - Gonzalo Yebra
- Department of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Rodrigo Bacigalupe
- Department of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh, UK
- Laboratory of Molecular Biology, Rega Institute for Medical Research, KU Leuven, Belgium
| | | | - Roberto M. C. Guedes
- Veterinary School, Department of Clinic and Surgery, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Magdalena Jacobson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tomasz Stadejek
- Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
- ANSES Fougères Laboratory, 10B rue Claude Bourgelat, Javené CS 40608, BP 90203, 35306 FOUGÈRES, France
| | - Alan L. Archibald
- Department of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - J. Ross Fitzgerald
- Department of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Tahar Ait-Ali
- Department of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh, UK
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10
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Benoit SL, Maier RJ, Sawers RG, Greening C. Molecular Hydrogen Metabolism: a Widespread Trait of Pathogenic Bacteria and Protists. Microbiol Mol Biol Rev 2020; 84:e00092-19. [PMID: 31996394 PMCID: PMC7167206 DOI: 10.1128/mmbr.00092-19] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pathogenic microorganisms use various mechanisms to conserve energy in host tissues and environmental reservoirs. One widespread but often overlooked means of energy conservation is through the consumption or production of molecular hydrogen (H2). Here, we comprehensively review the distribution, biochemistry, and physiology of H2 metabolism in pathogens. Over 200 pathogens and pathobionts carry genes for hydrogenases, the enzymes responsible for H2 oxidation and/or production. Furthermore, at least 46 of these species have been experimentally shown to consume or produce H2 Several major human pathogens use the large amounts of H2 produced by colonic microbiota as an energy source for aerobic or anaerobic respiration. This process has been shown to be critical for growth and virulence of the gastrointestinal bacteria Salmonella enterica serovar Typhimurium, Campylobacter jejuni, Campylobacter concisus, and Helicobacter pylori (including carcinogenic strains). H2 oxidation is generally a facultative trait controlled by central regulators in response to energy and oxidant availability. Other bacterial and protist pathogens produce H2 as a diffusible end product of fermentation processes. These include facultative anaerobes such as Escherichia coli, S Typhimurium, and Giardia intestinalis, which persist by fermentation when limited for respiratory electron acceptors, as well as obligate anaerobes, such as Clostridium perfringens, Clostridioides difficile, and Trichomonas vaginalis, that produce large amounts of H2 during growth. Overall, there is a rich literature on hydrogenases in growth, survival, and virulence in some pathogens. However, we lack a detailed understanding of H2 metabolism in most pathogens, especially obligately anaerobic bacteria, as well as a holistic understanding of gastrointestinal H2 transactions overall. Based on these findings, we also evaluate H2 metabolism as a possible target for drug development or other therapies.
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Affiliation(s)
- Stéphane L Benoit
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Robert J Maier
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - R Gary Sawers
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
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Resende TP, Medida RL, Guo Y, Vannucci FA, Saqui-Salces M, Gebhart C. Evaluation of mouse enteroids as a model for Lawsonia intracellularis infection. Vet Res 2019; 50:57. [PMID: 31324204 PMCID: PMC6642515 DOI: 10.1186/s13567-019-0672-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/05/2019] [Indexed: 12/16/2022] Open
Abstract
Lawsonia intracellularis, an obligate intracellular bacterium, is an important enteric pathogen in pig herds and horse farms worldwide. The hallmark feature of L. intracellularis infection is the proliferation of epithelial cells in intestinal crypts. A major limitation to the study of L. intracellularis infection is the lack of an in vitro model that reproduces the changes observed in proliferative enteropathy. Here we investigated the suitability of mouse enteroids as a model to study L. intracellularis infection. Mouse enteroids were microinjected with L. intracellularis, filter-sterilized L. intracellularis culture supernatant, or sterile cell culture media (DMEM). L. intracellularis antigen was detected in mouse enteroids by immunohistochemistry and was located mostly in the basal region of the epithelium. There was no differential growth of enteroids among treatment groups, and cellular proliferation was not increased in L. intracellularis-infected enteroids in relation to non-infected enteroids based on immunofluorescence staining. L. intracellularis infection did not induce changes in gene expression of Ki-67 (proliferation marker), Sox9 (marker for transit amplifying cells) and Muc2 (marker for goblet cells). These results indicate that although L. intracellularis antigen is detectable in mouse enteroids, indicating susceptibility to infection, mouse enteroids fail to replicate the cellular proliferation and gene expression changes observed in proliferative enteropathy. Nevertheless, we have successfully demonstrated that mouse enteroids can be used to model days-long intracellular pathogen infection, serving as potential models for the study of other pathogens of interest in veterinary medicine.
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Affiliation(s)
- Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.
| | - Ramya Lekha Medida
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, 55108, USA
| | - Yue Guo
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, 55108, USA
| | - Fabio A Vannucci
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Milena Saqui-Salces
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, 55108, USA
| | - Connie Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.,Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
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12
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Obradovic M, Pasternak JA, Hon Ng S, Allan B, Brownlie R, Wilson HL. Immunoproteomic analysis of Lawsonia intracellularis identifies candidate neutralizing antibody targets for use in subunit vaccine development. Vet Microbiol 2019; 235:270-279. [PMID: 31383312 DOI: 10.1016/j.vetmic.2019.07.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/28/2019] [Accepted: 07/18/2019] [Indexed: 12/17/2022]
Abstract
Lawsonia intracellularis is an obligate intracellular microorganism and the causative agent of porcine proliferative enteropathy. Due to its obligate intracellular nature, characterization of antigens and proteins involved in host-pathogen interaction and immune recognition have been difficult to achieve using conventional microbiological techniques. In this work, we used 2-dimensional gel electrophoresis coupled with Western-immunoblotting, mass spectrometry and bioinformatics to identify bacterial proteins that interact in vitro with pig intestinal cells (IPEC-1), have immunogenic properties and the potential to be used as subunit vaccine antigens. We detected eleven immunogenic bacterial proteins from which fliC (LI0710), LI1153 (annotated by NCBI as Putative protein N), and LI0649 (annotated as autotransporter) were predicted to be expressed on the outer membrane while LI0169 (oppA; annotated as ABC dipeptide transport system) was predicted to be periplasmic with a transmembrane domain forming a central pore through the plasma membrane. Genes coding for these four proteins were cloned and expressed in Escherichia coli and the corresponding recombinant proteins were purified using affinity chromatography. Porcine hyperimmune serum against whole Lawsonia lysate established that all four recombinant proteins were immunogenic. Further, rabbit hyperimmune sera generated against the vaccine strain of L. intracellularis and rabbit serum specific for each recombinant protein showed an inhibitory effect on the attachment and penetration of live, avirulent L. intracellularis, thus indicating that each protein is a potential neutralizing antibody target and a candidate for subunit vaccine formulation.
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Affiliation(s)
- Milan Obradovic
- Vaccine and Infectious Disease Organization (VIDO)-International Vaccine Centre (InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E3, Canada; School of Public Health, Vaccinology and Immunotherapeutics, Saskatchewan, Canada
| | - J Alex Pasternak
- Large Animal Clinical Sciences (LACS), Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5B4, Canada
| | - Siew Hon Ng
- Vaccine and Infectious Disease Organization (VIDO)-International Vaccine Centre (InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E3, Canada
| | - Brenda Allan
- Vaccine and Infectious Disease Organization (VIDO)-International Vaccine Centre (InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E3, Canada
| | - Robert Brownlie
- Vaccine and Infectious Disease Organization (VIDO)-International Vaccine Centre (InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E3, Canada
| | - Heather L Wilson
- Vaccine and Infectious Disease Organization (VIDO)-International Vaccine Centre (InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E3, Canada; School of Public Health, Vaccinology and Immunotherapeutics, Saskatchewan, Canada.
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13
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Leite FL, Vasquez E, Gebhart CJ, Isaacson RE. The effects of Lawsonia intracellularis, Salmonella enterica serovar Typhimurium and co-infection on IL-8 and TNFα expression in IPEC-J2 cells. Vet Microbiol 2019; 231:76-79. [PMID: 30955828 DOI: 10.1016/j.vetmic.2019.02.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 02/06/2019] [Accepted: 02/28/2019] [Indexed: 01/03/2023]
Abstract
Lawsonia intracellularis is among the most important enteric pathogens of swine and has been shown to be a risk factor for increased Salmonella enterica shedding. S. enterica serovar Typhimurium, in addition to being a significant pathogen of swine, also remains one of the most common causes of foodborne illness worldwide. Inflammation and the expression of IL8 and TNFα are an important process in the establishment of S. Typhimurium infection. Yet the effect of L. intracellularis on the expression of these cytokines by enterocytes, the niche both pathogens occupy during infection, is poorly understood. In this study we compared cytokine gene expression between singly and dually infected IPEC-J2 cells, a non-transformed porcine enterocyte cell line. Our results show that L. intracellularis leads to increased expression of IL8 and TNFα and has an additive effect on their expression in co-infection. The increase in expression of inflammatory cytokines may be one mechanism by which L. intracellularis favors S. Typhimurium infection.
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Affiliation(s)
- Fernando L Leite
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
| | - Erika Vasquez
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
| | - Connie J Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
| | - Richard E Isaacson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
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14
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Montesino R, Gutiérrez N, Camacho F, Farnós O, Andrades S, González A, Acosta J, Cortez-San Martín M, Sánchez O, Ruiz A, Toledo J. Multi-antigenic recombinant subunit vaccine against Lawsonia intracellularis: The etiological agent of porcine proliferative enteropathy. Vaccine 2019; 37:1340-1349. [DOI: 10.1016/j.vaccine.2019.01.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 11/30/2022]
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15
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Wattanaphansak S, Pereira CER, Kaenson W, Assavacheep P, Tantilertcharoen R, Resende TP, Barrera-Zarate JA, de Oliveira-Lee JSV, Klein U, Gebhart CJ, Guedes RMC. Isolation and in vitro antimicrobial susceptibility of porcine Lawsonia intracellularis from Brazil and Thailand. BMC Microbiol 2019; 19:27. [PMID: 30704407 PMCID: PMC6357443 DOI: 10.1186/s12866-019-1397-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 01/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lawsonia intracellularis is an obligate intracellular bacterium which cannot be cultured by conventional bacteriological methods. Furthermore, L. intracellularis needs enriched medium and a unique atmosphere for isolation, cultivation and propagation. Because of this,there are only a few isolates of L. intracellularis available and few studies in vitro demonstrating the susceptibility of this bacterium to antimicrobial agents. The objectives of this study were to isolate South American and Southeast Asia strains of L.intracellularis and to determine the in vitro antimicrobial activity against these isolates. Tested antimicrobials included: chlortetracycline, lincomycin, tiamulin, tylosin and valnemulin(against both Brazilian and Thailand strains) and additionally, amoxicillin, zinc-bacitracin, carbadox, enrofloxacin, gentamicin, sulfamethazine, trimethoprim, spectinomycin and a combination (1:1) of spectinomycin and lincomycin were also tested against the Thai isolates. The minimum inhibitory concentration (MIC) was determined by the antimicrobial activity that inhibited 99% of L. intracellularis growth in a cell culture as compared to the control (antimicrobial-free). RESULTS Two strains from Brazil and three strains from Thailand were successfully isolated and established in cell culture. Each antimicrobial was evaluated for intracellular and extracellular activity. Pleuromutilin group (valnemulin and tiamulin) and carbadox were the most active against L. intracellularis strains tested. Tylosin showed intermediate activity, chlortetracycline had variable results between low and intermediate activity, as well as spectinomycin, spectinomycin and lincomycin, amoxicillin, sulfamethazine and enrofloxacin. L. intracellularis was resistant to lincomycin, gentamicin, trimethoprim, colistin and bacitracin in in vitro conditions. CONCLUSIONS This is the first report of isolation of L. intracellularis strains from South America and Southeast Asia and characterization of the antimicrobial susceptibility patterns of these new strains.
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Affiliation(s)
- Suphot Wattanaphansak
- Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok, 10330, Thailand
| | - Carlos Eduardo Real Pereira
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Wenika Kaenson
- Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok, 10330, Thailand
| | - Pornchalit Assavacheep
- Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok, 10330, Thailand
| | - Rachod Tantilertcharoen
- Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok, 10330, Thailand
| | - Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Javier Alberto Barrera-Zarate
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Juliana Saes Vilaça de Oliveira-Lee
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Ulrich Klein
- Elanco Animal Health Inc., Mattenstrasse 24A, 4058, Basel, Switzerland
| | - Connie Jane Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Roberto Maurício Carvalho Guedes
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
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16
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Pereira CER, Resende TP, Vasquez E, Marshall‐Lund L, Guedes RMC, Gebhart CJ. In vitro antimicrobial activity against equine
Lawsonia intracellularis
strains. Equine Vet J 2019; 51:665-668. [DOI: 10.1111/evj.13071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 12/31/2018] [Indexed: 11/29/2022]
Affiliation(s)
- C. E. R. Pereira
- Department of Veterinary Clinic and Surgery Veterinary School Universidade Federal de Minas Gerais Belo Horizonte Minas Gerais Brazil
| | - T. P. Resende
- Department of Veterinary and Biomedical Sciences College of Veterinary Medicine University of Minnesota St. Paul Minnesota USA
| | - E. Vasquez
- Department of Veterinary and Biomedical Sciences College of Veterinary Medicine University of Minnesota St. Paul Minnesota USA
| | - L. Marshall‐Lund
- Department of Veterinary and Biomedical Sciences College of Veterinary Medicine University of Minnesota St. Paul Minnesota USA
| | - R. M. C. Guedes
- Department of Veterinary Clinic and Surgery Veterinary School Universidade Federal de Minas Gerais Belo Horizonte Minas Gerais Brazil
| | - C. J. Gebhart
- Department of Veterinary and Biomedical Sciences College of Veterinary Medicine University of Minnesota St. Paul Minnesota USA
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17
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Antimicrobial Resistance in Leptospira, Brucella, and Other Rarely Investigated Veterinary and Zoonotic Pathogens. Microbiol Spectr 2019; 6. [PMID: 30027885 DOI: 10.1128/microbiolspec.arba-0029-2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Leptospira, Brucella, and Borrelia are major agents of zoonotic disease, causing high morbidity and, in some cases, significant mortality in humans. For all three genera, prompt diagnosis and appropriate antimicrobial therapy are required to prevent the development of chronic, debilitating illness. Leptospira spp. are intrinsically resistant to several antimicrobial classes; however, there is little evidence in the literature for development of acquired resistance to antimicrobial agents used for clinical treatment of acute leptospirosis. For Brucella infections, there are numerous reports of relapses following therapy, but it is unclear whether this is due to sequestration within infected sites (e.g., bone) or the development of acquired resistance. Brucella have maintained their susceptibility to doxycycline and rifampicin, which in combination remain the most common treatments of brucellosis in humans. In vitro induced point mutations are described as imparting resistance to rifampicin (rpoB) and fluoroquinolones (gyrA). The clinical significance of these mutations is unclear. For Borrelia burgdorferi, although acquired resistance to some antimicrobial agents has been described, resistance due to bacterial persister cells surviving in the presence of antimicrobial, with no apparent increase in the MIC of the organism, have been recently described. Of the remaining veterinary fastidious pathogens, Lawsonia intracellularis is the most interesting from an antimicrobial resistance perspective because it can only be grown in cell culture, making in vitro susceptibility testing challenging. MIC testing has been undertaken on a small number of isolates, and some differences in susceptibility to macrolides have been demonstrated between isolates obtained from different regions.
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18
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Resende TP, Pereira CER, Daniel AGDS, Vasquez E, Saqui-Salces M, Vannucci FA, Gebhart CJ. Effects of Lawsonia intracellularis infection in the proliferation of different mammalian cell lines. Vet Microbiol 2018; 228:157-164. [PMID: 30593362 DOI: 10.1016/j.vetmic.2018.11.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 10/27/2022]
Abstract
Lawsonia intracellularis is an obligate intracellular bacterium that causes proliferative enteropathy in various animal species. While cellular proliferation of intestinal cells is recognized as the hallmark of L. intracellularis infection in vivo, it has not been demonstrated in in vitro models. In order to assay the effect of L. intracellularis, various cell lines were infected with pathogenic and non-pathogenic passages of the bacterium. Because of the high proliferative rate of these cell lines, serum deprivation, which is known to reduce proliferation, was applied to each of the cell lines to allow the observation of proliferation induced by L. intracellularis. Using antibodies for Ki-67 and L. intracellularis in dual immunofluorescence staining, we observed that L. intracellularis was more frequently observed in proliferating cells. Based on wound closure assays and on the amount of eukaryotic DNA content measured over time, we found no indication that cell lines infected with L. intracellularis increased proliferation and migration when compared to non-infected cells (p > 0.05). Cell arrest due to decreased serum in the culture media was cell-line dependent. Taken together, our findings provide data to support and expand previous subjective observations of the absence of in vitro proliferation caused by L. intracellularis in cell cultures and confirm that cell lines infected by L. intracellularis fail to serve as adequate models for understanding the cellular changes observed in proliferative enteropathy-affected intestines.
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Affiliation(s)
- Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA.
| | - Carlos Eduardo Real Pereira
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Amanda Gabrielle de Souza Daniel
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Erika Vasquez
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Milena Saqui-Salces
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences (CFANS), University of Minnesota, St. Paul, MN 55108, USA
| | - Fabio A Vannucci
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Connie Jane Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
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19
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Use of flow cytometry and PCR analysis to detect 5-carboxyfluoroscein-stained obligate intracellular bacteria Lawsonia intracellularis invasion of McCoy cells. J Microbiol Methods 2016; 126:60-6. [PMID: 27154728 DOI: 10.1016/j.mimet.2016.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 04/29/2016] [Indexed: 11/23/2022]
Abstract
In this study, we describe a method to quantify invasion of obligate intracellular bacteria, Lawsonia intracellularis, inside McCoy cells. In immunological research, the cell-permeable fluorescent dye 5'-carboxyfluoroscein succidyl ester (CFSE) is commonly used to quantify eukaryotic cellular proliferation. Instead of using it in this traditional way, we stained L. intracellularis with CFSE dye prior to infection of McCoy cells. Flow cytometry was performed to quantify the percentage of eukaryotic cells which had taken up or were associated with fluorescent bacteria. As obligate intracellular bacteria, they cannot replicate outside of eukaryotic cells and thus qPCR analysis was used to quantify bacterial growth. Indirectly, PCR analysis confirmed invasion rather than adherence to the McCoy cell surface. Fluorescent activated cell sorting (FACS) was used to sort the CFSE(+) (i.e. infected) McCoy cells from the CFSE(-) (i.e. non-infected) McCoy cells and confocal microscopy was used to confirm bacterial invasion and cytosolic localization of CFSE-L. intracellularis. To show that this approach could be used in conjunction with functional assays, we investigated the effect that serum antibodies had on CFSE-bacterial invasion and growth. Instead of blocking invasion, rabbit hyperimmune serum augmented invasion of the bacteria inside McCoy cells and qPCR analysis confirmed bacterial growth over the course of 5days. We conclude that CFSE-labeling of bacteria and qPCR can be used to track and quantify bacterial invasion and may be a valuable tool for studying the invasive properties of bacteria, especially if commercial antibodies are not available. This approach may be adapted for use in other obligate intracellular bacteria and intracellular pathogens.
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20
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Vannucci FA, Gebhart CJ. Recent Advances in Understanding the Pathogenesis of Lawsonia intracellularis Infections. Vet Pathol 2014; 51:465-77. [DOI: 10.1177/0300985813520249] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Proliferative enteropathy is an infectious disease caused by an obligate intracellular bacterium, Lawsonia intracellularis, and characterized by thickening of the intestinal epithelium due to enterocyte proliferation. The disease is endemic in swine herds and has been occasionally reported in various other species. Furthermore, outbreaks among foals began to be reported on breeding farms worldwide within the past 5 years. Cell proliferation is directly associated with bacterial infection and replication in the intestinal epithelium. As a result, mild to severe diarrhea is the major clinical sign described in infected animals. The dynamics of L. intracellularis infection in vitro and in vivo have been well characterized, but little is known about the genetic basis for the pathogenesis or ecology of this organism. The present review focuses on the recent advances regarding the pathogenesis and host-pathogen interaction of L. intracellularis infections.
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Affiliation(s)
- F. A. Vannucci
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St Paul, MN, USA
| | - C. J. Gebhart
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St Paul, MN, USA
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21
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Vannucci FA, Foster DN, Gebhart CJ. Laser microdissection coupled with RNA-seq analysis of porcine enterocytes infected with an obligate intracellular pathogen (Lawsonia intracellularis). BMC Genomics 2013; 14:421. [PMID: 23800029 PMCID: PMC3718617 DOI: 10.1186/1471-2164-14-421] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 06/18/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Lawsonia intracellularis is an obligate intracellular bacterium and the etiologic agent of proliferative enteropathy. The disease is endemic in pigs, emerging in horses and has been described in various other species including nonhuman primates. Cell proliferation is associated with bacterial replication in enterocyte cytoplasm, but the molecular basis of the host-pathogen interaction is unknown. We used laser capture microdissection coupled with RNA-seq technology to characterize the transcriptional responses of infected enterocytes and the host-pathogen interaction. RESULTS Proliferative enterocytes was associated with activation of transcription, protein biosynthesis and genes acting on the G1 phase of the host cell cycle (Rho family). The lack of differentiation in infected enterocytes was demonstrated by the repression of membrane transporters related to nutrient acquisition. The activation of the copper uptake transporter by infected enterocytes was associated with high expression of the Zn/Cu superoxide dismutase by L. intracellularis. This suggests that the intracellular bacteria incorporate intracytoplasmic copper and express a sophisticated mechanism to cope with oxidative stress. CONCLUSIONS The feasibility of coupling microdissection and RNA-seq was demonstrated by characterizing the host-bacterial interactions from a specific cell type in a heterogeneous tissue. High expression of L. intracellularis genes encoding hypothetical proteins and activation of host Rho genes infers the role of unrecognized bacterial cyclomodulins in the pathogenesis of proliferative enteropathy.
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Affiliation(s)
- Fabio A Vannucci
- Department of Veterinary and Biomedical Science , College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Douglas N Foster
- Department of Animal Science, College of Food, Agricultural and Natural Resource Science, University of Minnesota, St. Paul, MN, USA
| | - Connie J Gebhart
- Department of Veterinary and Biomedical Science , College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
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22
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Vannucci FA, Foster DN, Gebhart CJ. Comparative transcriptional analysis of homologous pathogenic and non-pathogenic Lawsonia intracellularis isolates in infected porcine cells. PLoS One 2012; 7:e46708. [PMID: 23056413 PMCID: PMC3463550 DOI: 10.1371/journal.pone.0046708] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 09/04/2012] [Indexed: 11/19/2022] Open
Abstract
Lawsonia intracellularis is the causative agent of proliferative enteropathy. This disease affects various animal species, including nonhuman primates, has been endemic in pigs, and is an emerging concern in horses. Non-pathogenic variants obtained through multiple passages in vitro do not induce disease, but bacterial isolates at low passage induce clinical and pathological changes. We hypothesize that genes differentially expressed between pathogenic (passage 10) and non-pathogenic (passage 60) L. intracellularis isolates encode potential bacterial virulence factors. The present study used high-throughput sequencing technology to characterize the transcriptional profiling of a pathogenic and a non-pathogenic homologous L. intracellularis variant during in vitro infection. A total of 401 genes were exclusively expressed by the pathogenic variant. Plasmid-encoded genes and those involved in membrane transporter (e.g. ATP-binding cassette), adaptation and stress response (e.g. transcriptional regulators) were the categories mostly responsible for this wider transcriptional landscape. The entire gene repertoire of plasmid A was repressed in the non-pathogenic variant suggesting its relevant role in the virulence phenotype of the pathogenic variant. Of the 319 genes which were commonly expressed in both pathogenic and non-pathogenic variants, no significant difference was observed by comparing their normalized transcription levels (fold change±2; p<0.05). Unexpectedly, these genes demonstrated a positive correlation (r(2) = 0.81; p<0.05), indicating the involvement of gene silencing (switching off) mechanisms to attenuate virulence properties of the pathogenic variant during multiple cell passages. Following the validation of these results by reverse transcriptase-quantitative PCR using ten selected genes, the present study represents the first report characterizing the transcriptional profile of L. intracellularis. The complexity of the virulence phenotype was demonstrated by the diversity of genes exclusively expressed in the pathogenic isolate. The results support our hypothesis and provide the basis for prospective mechanistic studies regarding specific roles of target genes involved in the pathogenesis, diagnosis and control of proliferative enteropathy.
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Affiliation(s)
- Fabio A Vannucci
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America.
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