1
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Bowser S, Melton-Celsa A, Chapartegui-González I, Torres AG. Efficacy of EHEC gold nanoparticle vaccines evaluated with the Shiga toxin-producing Citrobacter rodentium mouse model. Microbiol Spectr 2024; 12:e0226123. [PMID: 38047703 PMCID: PMC10783022 DOI: 10.1128/spectrum.02261-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/16/2023] [Indexed: 12/05/2023] Open
Abstract
IMPORTANCE Enterohemorrhagic Escherichia coli (EHEC) remains an important cause of diarrheal disease and complications worldwide, especially in children, yet there are no available vaccines for human use. Inadequate pre-clinical evaluation due to inconsistent animal models remains a major barrier to novel vaccine development. We demonstrate the usefulness of Stx2d-producing Citrobacter rodentium in assessing vaccine effectiveness because it more closely recapitulates human disease caused by EHEC.
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Affiliation(s)
- Sarah Bowser
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Angela Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Itziar Chapartegui-González
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Alfredo G. Torres
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas, USA
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, USA
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2
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Fang F, Xue Y, Xu X, Fang D, Liu W, Zhong Y, Han J, Li Y, Tao Q, Lu R, Ma C, Kumar A, Wang D. L-glutamine protects against enterohemorrhagic Escherichia coli infection by inhibiting bacterial virulence and enhancing host defense concurrently. Microbiol Spectr 2023; 11:e0097523. [PMID: 37815335 PMCID: PMC10714755 DOI: 10.1128/spectrum.00975-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 08/24/2023] [Indexed: 10/11/2023] Open
Abstract
IMPORTANCE The type 3 secretion system (T3SS) was obtained in many Gram-negative bacterial pathogens, and it is crucial for their pathogenesis. Environmental signals were found to be involved in the expression regulation of T3SS, which was vital for successful bacterial infection in the host. Here, we discovered that L-glutamine (Gln), the most abundant amino acid in the human body, could repress enterohemorrhagic Escherichia coli (EHEC) T3SS expression via nitrogen metabolism and therefore had potential as an antivirulence agent. Our in vitro and in vivo evidence demonstrated that Gln could decline EHEC infection by attenuating bacterial virulence and enhancing host defense simultaneously. We repurpose Gln as a potential treatment for EHEC infection accordingly.
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Affiliation(s)
- Fang Fang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yunxin Xue
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Xuefang Xu
- State Key Laboratory of Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Dingli Fang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Weijia Liu
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Ying Zhong
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Jinping Han
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yunhe Li
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Qian Tao
- Department of Pathology, Women and Children's Hospital, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian Province, China
| | - Rong Lu
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Cong Ma
- Department of Nephrology, Lishan Hospital, Anshan Central Hospital, Anshan, Liaoning Province, China
| | | | - Dai Wang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
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3
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Wang J, Huang Y, Guan C, Li J, Yang H, Zhao G, Liu C, Ma J, Tang B. Characterization of an Escherichia coli Isolate Coharboring the Virulence Gene astA and Tigecycline Resistance Gene tet(X4) from a Dead Piglet. Pathogens 2023; 12:903. [PMID: 37513750 PMCID: PMC10385434 DOI: 10.3390/pathogens12070903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
tet(X4) is the critical resistance gene for tigecycline degradation that has been continually reported in recent years. In particular, pathogenic bacteria carrying tet(X4) are a severe threat to human health. However, information describing Escherichia coli coharboring tet(X4) with virulence genes is limited. Here, we isolated an E. coli strain coharboring tet(X4) and the heat-stable toxin gene astA from a dead piglet. The strain named 812A1-131 belongs to ST10. The genome was sequenced using the Nanopore and Illumina platforms. The virulence genes astA and tet(X4) are located on the chromosome and in the IncHI1-type plasmid p812A1-tetX4-193K, respectively. The plasmid could be conjugatively transferred to recipient E. coli J53 with high frequency. In vivo experiments showed that strain 812A1-131 is pathogenic to Galleria mellonella and could colonize the intestines of mice. In summary, pathogenic E. coli could receive a plasmid harboring the tet(X4) gene, which can increase the difficulty of treatment. The prevalence and transmission mechanisms of pathogenic bacteria coharboring the tet(X4) gene need more attention.
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Affiliation(s)
- Jianmei Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products & Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yuting Huang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products & Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
- School of Life Science and Engineering, Foshan University, Foshan 528225, China
| | - Chunjiu Guan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products & Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
- School of Life Science and Engineering, Foshan University, Foshan 528225, China
| | - Jie Li
- College of Life Science, Liaocheng University, Liaocheng 252000, China
| | - Hua Yang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products & Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Guoping Zhao
- School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Canying Liu
- School of Life Science and Engineering, Foshan University, Foshan 528225, China
| | - Jiangang Ma
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products & Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Biao Tang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products & Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
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4
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Herzog MKM, Cazzaniga M, Peters A, Shayya N, Beldi L, Hapfelmeier S, Heimesaat MM, Bereswill S, Frankel G, Gahan CG, Hardt WD. Mouse models for bacterial enteropathogen infections: insights into the role of colonization resistance. Gut Microbes 2023; 15:2172667. [PMID: 36794831 PMCID: PMC9980611 DOI: 10.1080/19490976.2023.2172667] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/18/2023] [Indexed: 02/17/2023] Open
Abstract
Globally, enteropathogenic bacteria are a major cause of morbidity and mortality.1-3 Campylobacter, Salmonella, Shiga-toxin-producing Escherichia coli, and Listeria are among the top five most commonly reported zoonotic pathogens in the European Union.4 However, not all individuals naturally exposed to enteropathogens go on to develop disease. This protection is attributable to colonization resistance (CR) conferred by the gut microbiota, as well as an array of physical, chemical, and immunological barriers that limit infection. Despite their importance for human health, a detailed understanding of gastrointestinal barriers to infection is lacking, and further research is required to investigate the mechanisms that underpin inter-individual differences in resistance to gastrointestinal infection. Here, we discuss the current mouse models available to study infections by non-typhoidal Salmonella strains, Citrobacter rodentium (as a model for enteropathogenic and enterohemorrhagic E. coli), Listeria monocytogenes, and Campylobacter jejuni. Clostridioides difficile is included as another important cause of enteric disease in which resistance is dependent upon CR. We outline which parameters of human infection are recapitulated in these mouse models, including the impact of CR, disease pathology, disease progression, and mucosal immune response. This will showcase common virulence strategies, highlight mechanistic differences, and help researchers from microbiology, infectiology, microbiome research, and mucosal immunology to select the optimal mouse model.
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Affiliation(s)
- Mathias K.-M. Herzog
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich, Switzerland
| | - Monica Cazzaniga
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
| | - Audrey Peters
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Nizar Shayya
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Luca Beldi
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | | | - Markus M. Heimesaat
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Stefan Bereswill
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Gad Frankel
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Cormac G.M. Gahan
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
- School of Pharmacy, University College Cork, Cork, Ireland
| | - Wolf-Dietrich Hardt
- Department of Biology, Institute of Microbiology, ETH Zurich, Zurich, Switzerland
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5
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Ismail HTH. The ameliorative efficacy of Thymus vulgaris essential oil against Escherichia coli O157:H7-induced hematological alterations, hepatorenal dysfunction and immune-inflammatory disturbances in experimentally infected rats. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:41476-41491. [PMID: 35088282 DOI: 10.1007/s11356-022-18896-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
The purpose of the present study was to evaluate the possible ameliorative role of Thymus vulgaris (T. vulgaris) essential oil against Escherichia coli O157:H7 (E. coli O157:H7) deleterious effects in both blood and different tissues of rats by assessing the hematological, biochemical and immune-inflammatory parameters besides the histopathological alterations in the different organs. Forty male rats were randomly divided into four equal groups as follows: group I served as control, group II orally inoculated with E. coli O157:H7 at a dose of 1.0 × 109 cfu/ml, group III orally received 250 mg/kg BW T. vulgaris oil daily for 7 days and group IV orally inoculated with E. coli O157:H7 as the same dose of group II and orally received T. vulgaris oil as the same dose and duration of group III. Bacterial challenge in groups II and IV was once at the beginning of experiment and administration of oil began after 72 h from bacterial inoculation. At the end of the study, blood was sampled and complete blood picture, liver and kidney function alongside immunoglobulins and cytokines concentrations were estimated and tissues of large intestine (colon), liver and kidneys were collected for histopathological examinations. The results revealed that there was an increase of red blood cells count, hematocrit value and hemoglobin concentration besides white blood cells and thrombocytes counts and substantial increment of serum markers of hepatorenal damage such as the activities of transaminases and concentrations of bilirubin (total, direct and indirect), total proteins, albumin, creatinine and urea in E. coli O157:H7-challenged group. Also, there was a considerable increase in serum immunoglobulins M and G, interleukin 6 and 8 and tumor necrosis factor alpha as well as decreased serum alkaline phosphatase activity. Moreover, T. vulgaris oil could partially improve the hematological, biochemical and histopathological alterations induced by E. coli O157:H7 without any significant alterations in all measured parameters when used alone. The study concluded that the T. vulgaris oil relatively diminished the alterations in hematological parameters, hepatic and renal function markers and immune-inflammatory variables alongside the histopathological changes in different organs induced by E. coli O157:H7. The ameliorative effects of T. vulgaris oil are mediated through its anti-inflammatory, antioxidant and immunomodulatory activities.
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Affiliation(s)
- Hager Tarek H Ismail
- Department of Clinical Pathology, Faculty of Veterinary Medicine, Zagazig University, 1 Alzeraa Street, Zagazig City, Postal Code 44511, Sharkia Province, Egypt.
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6
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Sensitive recognition of Shiga toxin using biosensor technology: An efficient platform towards bioanalysis of pathogenic bacterial. Microchem J 2022. [DOI: 10.1016/j.microc.2021.106900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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Kan A, Gelfat I, Emani S, Praveschotinunt P, Joshi NS. Plasmid Vectors for in Vivo Selection-Free Use with the Probiotic E. coli Nissle 1917. ACS Synth Biol 2021; 10:94-106. [PMID: 33301298 PMCID: PMC7813132 DOI: 10.1021/acssynbio.0c00466] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
Escherichia
coli Nissle 1917 (EcN) is a probiotic
bacterium, commonly employed to treat certain gastrointestinal disorders.
It is fast emerging as an important target for the development of
therapeutic engineered bacteria, benefiting from the wealth of knowledge
of E. coli biology and ease of manipulation.
Bacterial synthetic biology projects commonly utilize engineered plasmid
vectors, which are simple to engineer and can reliably achieve high
levels of protein expression. However, plasmids typically require
antibiotics for maintenance, and the administration of an antibiotic
is often incompatible with in vivo experimentation
or treatment. EcN natively contains plasmids pMUT1 and pMUT2, which
have no known function but are stable within the bacteria. Here, we
describe the development of the pMUT plasmids into a robust platform
for engineering EcN for in vivo experimentation,
alongside a CRISPR-Cas9 system to remove the native plasmids. We systematically
engineered both pMUT plasmids to contain selection markers, fluorescent
markers, temperature sensitive expression, and curli secretion systems
to export a customizable functional material into the extracellular
space. We then demonstrate that the engineered plasmids were maintained
in bacteria as the engineered bacteria pass through the mouse GI tract
without selection, and that the secretion system remains functional,
exporting functionalized curli proteins into the gut. Our plasmid
system presents a platform for the rapid development of therapeutic
EcN bacteria.
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Affiliation(s)
- Anton Kan
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - Ilia Gelfat
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sivaram Emani
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
- Harvard College, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Pichet Praveschotinunt
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Neel S. Joshi
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
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8
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Easwaran M, De Zoysa M, Shin HJ. Application of phage therapy: Synergistic effect of phage EcSw (ΦEcSw) and antibiotic combination towards antibiotic-resistant Escherichia coli. Transbound Emerg Dis 2020; 67:2809-2817. [PMID: 32453904 DOI: 10.1111/tbed.13646] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 04/20/2020] [Accepted: 05/15/2020] [Indexed: 11/30/2022]
Abstract
Bacteriophage therapy is acknowledged as a potential tool to prevent or treat multidrug-resistant bacterial infections. In this study, our major focus was on the bacteriolytic activity of phage EcSw (ΦEcSw) against the emergence of the clinically important Escherichia coli Sw1 and E. coli O157:H7. The amount of the antibiotics was changed in a concentration-dependent manner, and the ΦEcSw susceptibility to antibiotics was determined. The kanamycin and chloramphenicol inhibited the titre of phage, but ampicillin did not show phage inhibition. Though the kanamycin and chloramphenicol controlled the growth of Sw1 in a concentration-dependent manner, the ampicillin did not due to the resistance. The combined activity of the ΦEcSw with antibiotics (kanamycin and chloramphenicol) compared with the antibiotics alone showed significant lytic activity p < .001). In addition, phage-based therapy was evaluated for controlling the multidrug-resistant E. coli Sw1 and E. coli O157:H7 in zebrafish and BALB/c mice, respectively. Our results provide novel advantages of phage therapy and phage-antibiotic therapy to control antibiotic-resistant bacteria.
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Affiliation(s)
- Maheswaran Easwaran
- College of Veterinary Medicine, Chungnam National University, Daejeon, Korea
| | - Mahanama De Zoysa
- College of Veterinary Medicine, Chungnam National University, Daejeon, Korea
- Research Institute of Veterinary Medicine, Chungnam National University, Daejeon, Korea
| | - Hyun-Jin Shin
- College of Veterinary Medicine, Chungnam National University, Daejeon, Korea
- Research Institute of Veterinary Medicine, Chungnam National University, Daejeon, Korea
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9
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Kim SY, Kang SS. Anti-Biofilm Activities of Manuka Honey against Escherichia coli O157:H7. Food Sci Anim Resour 2020; 40:668-674. [PMID: 32734273 PMCID: PMC7372985 DOI: 10.5851/kosfa.2020.e42] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/18/2020] [Accepted: 05/31/2020] [Indexed: 11/29/2022] Open
Abstract
Manuka honey (MH) has been shown anti-bacterial activity against several
pathogenic bacteria. However, the inhibitory effect of MH on biofilm formation
by Escherichia coli O157:H7 has not yet been examined. In this
study, MH significantly reduced E. coli O157:H7 biofilm.
Moreover, pre- and post-treatment with MH also significantly reduced E.
coli O157:H7 biofilm. Cellular metabolic activities exhibited that
the viability of E. coli O157:H7 biofilm cells was reduced in
the presence of MH. Further, colony forming unit of MH-treated E.
coli O157:H7 biofilm was significantly reduced by over 70%.
Collectively, this study suggests the potential of anti-biofilm properties of MH
which could be applied to control E. coli O157:H7.
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Affiliation(s)
- Su-Yeon Kim
- Department of Food Science and Biotechnology, College of Life Science and Biotechnology, Dongguk University-Seoul, Goyang 10326, Korea
| | - Seok-Seong Kang
- Department of Food Science and Biotechnology, College of Life Science and Biotechnology, Dongguk University-Seoul, Goyang 10326, Korea
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10
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Kumar A, Russell RM, Pifer R, Menezes-Garcia Z, Cuesta S, Narayanan S, MacMillan JB, Sperandio V. The Serotonin Neurotransmitter Modulates Virulence of Enteric Pathogens. Cell Host Microbe 2020; 28:41-53.e8. [PMID: 32521224 DOI: 10.1016/j.chom.2020.05.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/30/2020] [Accepted: 05/05/2020] [Indexed: 02/06/2023]
Abstract
The gut-brain axis is crucial to microbial-host interactions. The neurotransmitter serotonin is primarily synthesized in the gastrointestinal (GI) tract, where it is secreted into the lumen and subsequently removed by the serotonin transporter, SERT. Here, we show that serotonin decreases virulence gene expression by enterohemorrhagic E. coli (EHEC) and Citrobacter rodentium, a murine model for EHEC. The membrane-bound histidine sensor kinase, CpxA, is a bacterial serotonin receptor. Serotonin induces dephosphorylation of CpxA, which inactivates the transcriptional factor CpxR controlling expression of virulence genes, notably those within the locus of enterocyte effacement (LEE). Increasing intestinal serotonin by genetically or pharmacologically inhibiting SERT decreases LEE expression and reduces C. rodentium loads. Conversely, inhibiting serotonin synthesis increases pathogenesis and decreases host survival. As other enteric bacteria contain CpxA, this signal exploitation may be engaged by other pathogens. Additionally, repurposing serotonin agonists to inhibit CpxA may represent a potential therapeutic intervention for enteric bacteria.
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Affiliation(s)
- Aman Kumar
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Regan M Russell
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Reed Pifer
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zelia Menezes-Garcia
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Santiago Cuesta
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sanjeev Narayanan
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - John B MacMillan
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Vanessa Sperandio
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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11
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Petro CD, Duncan JK, Seldina YI, Allué-Guardia A, Eppinger M, Riddle MS, Tribble DR, Johnson RC, Dalgard CL, Sukumar G, Connor P, Boisen N, Melton-Celsa AR. Genetic and Virulence Profiles of Enteroaggregative Escherichia coli (EAEC) Isolated From Deployed Military Personnel (DMP) With Travelers' Diarrhea. Front Cell Infect Microbiol 2020; 10:200. [PMID: 32509590 PMCID: PMC7251025 DOI: 10.3389/fcimb.2020.00200] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/16/2020] [Indexed: 02/01/2023] Open
Abstract
To discern if there was a particular genotype associated with clinical enteroaggregative Escherichia coli (EAEC) strains isolated from deployed military personnel (DMP) with travelers' diarrhea (TD), we characterized a collection of EAEC from DMP deployed to Afghanistan, Djibouti, Kenya, or Honduras. Although we did not identify a specific EAEC genotype associated with TD in DMP, we found that EAEC isolated at the first clinic visit were more likely to encode the dispersin gene aap than EAEC collected at follow-up visits. A majority of the EAEC isolates were typical EAEC that adhered to HEp-2 cells, formed biofilms, and harbored genes for aggregative adherence fimbriae (AAF), AggR, and serine protease autotransporters of Enterobacteriaceae (SPATEs). A separate subset of the EAEC had aggR and genes for SPATEs but encoded a gene highly homologous to that for CS22, a fimbriae more commonly found in enterotoxigenic E. coli. None of these CS22-encoding EAEC formed biofilms in vitro or adhered to HEp-2 cells. Whole genome sequence and single nucleotide polymorphism analyses demonstrated that most of the strains were genetically diverse, but that a few were closely related. Isolation of these related strains occurred within days to more than a year apart, a finding that suggests a persistent source and genomic stability. In an ampicillin-treated mouse model we found that an agg4A+ aar- isolate formed a biofilm in the intestine and caused reduced weight gain in mice, whereas a strain that did not form an in vivo biofilm caused no morbidity. Our diverse strain collection from DMP displays the heterogeneity of EAEC strains isolated from human patients, and our mouse model of infection indicated the genotype agg4A+ aar– and/or capacity to form biofilm in vivo may correlate to disease severity.
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Affiliation(s)
- Courtney D Petro
- Department of Microbiology and Immunolgy, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Jeffrey K Duncan
- Department of Microbiology and Immunolgy, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Yuliya I Seldina
- Walter Reed National Military Medical Center, Bethesda, MD, United States
| | - Anna Allué-Guardia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Mark Eppinger
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Mark S Riddle
- Department of Preventative Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - David R Tribble
- Department of Preventative Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Ryan C Johnson
- Department of Preventative Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Clifton L Dalgard
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.,The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Gauthaman Sukumar
- The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.,Collaborative Health Initiative Research Program, Henry Jackson Foundation, Bethesda, MD, United States
| | - Patrick Connor
- Military Enteric Disease Group, Academic Department of Military Medicine, Birmingham, United Kingdom
| | - Nadia Boisen
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Angela R Melton-Celsa
- Department of Microbiology and Immunolgy, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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12
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Arshadi N, Mousavi SL, Amani J, Nazarian S. Immunogenic Potency of Formalin and Heat Inactivated E. coli O157:H7 in Mouse Model Administered by Different Routes. Avicenna J Med Biotechnol 2020; 12:194-200. [PMID: 32695283 PMCID: PMC7368119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Enterohemorrhagic Escherichia coli (E. coli) (EHEC) O157:H7 is a major foodborne pathogen causing severe disease in humans worldwide. Cattle are important reservoirs of E. coli O157:H7 and developing a specific immunity in animals would be invaluable. The administration of Whole Cell Vaccines (WCV) is a well-established method of vaccination against bacterial infections. Route of administration, inactivation and using suitable adjuvant have significant effects on the characteristics and efficacy of WCV. METHODS In the present study, an attempt was made to evaluate the immunogenic potency of heat and formalin inactivated cells administered orally and subcutaneously in mouse model by ELISA. Mice pretreated with streptomycin were used as a model to evaluate the efficacy of subcutaneous versus oral administration of the vaccine. Following immunization, mice were infected with E. coli O157:H7 and feces were monitored for shedding. RESULTS Both forms of inactivated cells induced immune response and hence protection against infectious diseases caused by E. coli O157:H7. However, formalin inactivated cells of E. coli O157:H7 showed superior antigenicity compared to heat inactivated cells. Subcutaneous immunization of mice with both heat and formalin inactivated E. coli O157:H7 induced significant specific levels of IgG antibodies but did not lead to significant antigen-specific IgA rise in feces, whereas oral immunization elicited significant levels of IgG antibodies with some animals developing antigen-specific IgA in feces. CONCLUSION Inactivated E. coli O157:H7 is highly immunogenic and can induce protective immune responses via oral immunization.
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Affiliation(s)
- Nasim Arshadi
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
| | - Seyed Latif Mousavi
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran,Corresponding author: Seyed Latif Mousavi, Ph.D., Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran, Tel: +98 21 51212232, E-mail:
| | - Jafar Amani
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
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13
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Xu X, Zhang H, Huang Y, Zhang Y, Wu C, Gao P, Teng Z, Luo X, Peng X, Wang X, Wang D, Pu J, Zhao H, Lu X, Lu S, Ye C, Dong Y, Lan R, Xu J. Beyond a Ribosomal RNA Methyltransferase, the Wider Role of MraW in DNA Methylation, Motility and Colonization in Escherichia coli O157:H7. Front Microbiol 2019; 10:2520. [PMID: 31798540 PMCID: PMC6863780 DOI: 10.3389/fmicb.2019.02520] [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: 05/09/2019] [Accepted: 10/18/2019] [Indexed: 12/31/2022] Open
Abstract
MraW is a 16S rRNA methyltransferase and plays a role in the fine-tuning of the ribosomal decoding center. It was recently found to contribute to the virulence of Staphylococcus aureus. In this study, we examined the function of MraW in Escherichia coli O157:H7 and found that the deletion of mraW led to decreased motility, flagellar production and DNA methylation. Whole-genome bisulfite sequencing showed a genome wide decrease of methylation of 336 genes and 219 promoters in the mraW mutant including flagellar genes. The methylation level of flagellar genes was confirmed by bisulfite PCR sequencing. Quantitative reverse transcription PCR results indicated that the transcription of these genes was also affected. MraW was furtherly observed to directly bind to the four flagellar gene sequences by electrophoretic mobility shift assay (EMSA). A common flexible motif in differentially methylated regions (DMRs) of promoters and coding regions of the four flagellar genes was identified. Reduced methylation was correlated with altered expression of 21 of the 24 genes tested. DNA methylation activity of MraW was confirmed by DNA methyltransferase activity assay in vitro and repressed by DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-aza). In addition, the mraW mutant colonized poorer than wild type in mice. We also found that the expression of mraZ in the mraW mutant was increased confirming the antagonistic effect of mraW on mraZ. In conclusion, mraW was found to be a DNA methylase and have a wide-ranging effect on E. coli O157:H7 including motility and virulence in vivo via genome wide methylation and mraZ antagonism.
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Affiliation(s)
- Xuefang Xu
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Heng Zhang
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Ying Huang
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Yuan Zhang
- China Institute of Veterinary Drug Control, Haidian, China
| | - Changde Wu
- College of Animal Sciences and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Pengya Gao
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,College of Animal Sciences and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Zhongqiu Teng
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xuelian Luo
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xiaojing Peng
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xiaoyuan Wang
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Dai Wang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Ji Pu
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Hongqing Zhao
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xuancheng Lu
- Laboratory Animal Center, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Shuangshuang Lu
- Laboratory Animal Center, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Changyun Ye
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Yuhui Dong
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jianguo Xu
- State Key Laboratory for Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
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14
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Balasubramanian S, Osburne MS, BrinJones H, Tai AK, Leong JM. Prophage induction, but not production of phage particles, is required for lethal disease in a microbiome-replete murine model of enterohemorrhagic E. coli infection. PLoS Pathog 2019; 15:e1007494. [PMID: 30629725 PMCID: PMC6328086 DOI: 10.1371/journal.ppat.1007494] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/01/2018] [Indexed: 12/12/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) colonize intestinal epithelium by generating characteristic attaching and effacing (AE) lesions. They are lysogenized by prophage that encode Shiga toxin 2 (Stx2), which is responsible for severe clinical manifestations. As a lysogen, prophage genes leading to lytic growth and stx2 expression are repressed, whereas induction of the bacterial SOS response in response to DNA damage leads to lytic phage growth and Stx2 production both in vitro and in germ-free or streptomycin-treated mice. Some commensal bacteria diminish prophage induction and concomitant Stx2 production in vitro, whereas it has been proposed that phage-susceptible commensals may amplify Stx2 production by facilitating successive cycles of infection in vivo. We tested the role of phage induction in both Stx production and lethal disease in microbiome-replete mice, using our mouse model encompassing the murine pathogen Citrobacter rodentium lysogenized with the Stx2-encoding phage Φstx2dact. This strain generates EHEC-like AE lesions on the murine intestine and causes lethal Stx-mediated disease. We found that lethal mouse infection did not require that Φstx2dact infect or lysogenize commensal bacteria. In addition, we detected circularized phage genomes, potentially in the early stage of replication, in feces of infected mice, confirming that prophage induction occurs during infection of microbiota-replete mice. Further, C. rodentium (Φstx2dact) mutants that do not respond to DNA damage or express stx produced neither high levels of Stx2 in vitro or lethal infection in vivo, confirming that SOS induction and concomitant expression of phage-encoded stx genes are required for disease. In contrast, C. rodentium (Φstx2dact) mutants incapable of prophage genome excision or of packaging phage genomes retained the ability to produce Stx in vitro, as well as to cause lethal disease in mice. Thus, in a microbiome-replete EHEC infection model, lytic induction of Stx-encoding prophage is essential for lethal disease, but actual phage production is not.
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Affiliation(s)
- Sowmya Balasubramanian
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Marcia S. Osburne
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Haley BrinJones
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
| | - Albert K. Tai
- Department of Immunology at Tufts University School of Medicine, Boston, MA, United States of America
| | - John M. Leong
- Department of Molecular Biology and Microbiology at Tufts University School of Medicine, Boston, MA, United States of America
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15
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Stromberg ZR, Van Goor A, Redweik GAJ, Wymore Brand MJ, Wannemuehler MJ, Mellata M. Pathogenic and non-pathogenic Escherichia coli colonization and host inflammatory response in a defined microbiota mouse model. Dis Model Mech 2018; 11:dmm035063. [PMID: 30275104 PMCID: PMC6262807 DOI: 10.1242/dmm.035063] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/24/2018] [Indexed: 12/17/2022] Open
Abstract
Most Escherichia coli strains in the human intestine are harmless. However, enterohemorrhagic Ecoli (EHEC) is a foodborne pathogen that causes intestinal disease in humans. Conventionally reared (CONV) mice are inconsistent models for human infections with EHEC because they are often resistant to Ecoli colonization, in part due to their gastrointestinal (GI) microbiota. Although antibiotic manipulation of the mouse microbiota has been a common means to overcome colonization resistance, these models have limitations. Currently, there are no licensed treatments for clinical EHEC infections and, thus, new tools to study EHEC colonization need to be developed. Here, we used a defined microbiota mouse model, consisting of the altered Schaedler flora (ASF), to characterize intestinal colonization and compare host responses following colonization with EHEC strain 278F2 or non-pathogenic Ecoli strain MG1655. Significantly higher (P<0.05) levels of both strains were found in feces and cecal and colonic contents of C3H/HeN ASF compared to C3H/HeN CONV mice. GI inflammation was significantly elevated (P<0.05) in the cecum of EHEC 278F2-colonized compared to E. coli MG1655-colonized C3H/HeN ASF mice. In addition, EHEC 278F2 differentially modulated inflammatory-associated genes in colonic tissue of C3H/HeN ASF mice compared to E. coli MG1655-colonized mice. This approach allowed for prolonged colonization of the murine GI tract by pathogenic and non-pathogenic Ecoli strains, and for evaluation of host inflammatory processes. Overall, this system can be used as a powerful tool for future studies to assess therapeutics, microbe-microbe interactions, and strategies for preventing EHEC infections.
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Affiliation(s)
- Zachary R Stromberg
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Angelica Van Goor
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Graham A J Redweik
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Meghan J Wymore Brand
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA 50011, USA
| | - Michael J Wannemuehler
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA 50011, USA
| | - Melha Mellata
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
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16
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Dextran Sulfate Sodium Colitis Facilitates Colonization with Shiga Toxin-Producing Escherichia coli: a Novel Murine Model for the Study of Shiga Toxicosis. Infect Immun 2018; 86:IAI.00530-18. [PMID: 30150257 DOI: 10.1128/iai.00530-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/23/2018] [Indexed: 12/23/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) bacteria are globally important gastrointestinal pathogens causing hemorrhagic gastroenteritis with variable progression to potentially fatal Shiga toxicosis. Little is known about the potential effects of E. coli-derived Shiga-like toxins (STXs) on host gastrointestinal immune responses during infection, in part due to the lack of a reproducible immunocompetent-animal model of STEC infection without depleting the commensal microbiota. Here, we describe a novel and reproducible murine model utilizing dextran sulfate sodium (DSS) colitis to induce susceptibility to colonization with clinical-isolate STEC strains. After exposure to DSS and subsequent oral STEC challenge, all the mice were colonized, and 66% of STEC-infected mice required early euthanasia. Morbidity during STEC infection, but not infection with an isogenic STEC mutant with toxin deleted, was associated with increased renal transcripts of the injury markers KIM1 and NGAL, histological evidence of renal tubular injury, and increased renal interleukin 6 gene (IL-6) and CXCL1 inflammatory transcripts. Interestingly, the intestinal burden of STEC during infection was increased compared to its isogenic Shiga toxin deletion strain. Increased bacterial burdens during Shiga toxin production coincided with decreased induction of colonic IL-23 axis transcripts known to be critical for clearance of similar gastrointestinal pathogens in mice, suggesting a previously undescribed role for STEC Shiga toxins in suppressing host immune responses during STEC infection and survival. The DSS+STEC model establishes infection with clinical-isolate strains of STEC in immunocompetent mice without depleting the gastrointestinal microbiota, enabling characterization of the effects of STXs on the IL-23 axis and other gastrointestinal pathogen-host interactions.
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17
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Khan SB, Zou G, Xiao R, Cheng Y, Rehman ZU, Ali S, Memon AM, Fahad S, Ahmad I, Zhou R. Prevalence, quantification and isolation of pathogenic shiga toxin Escherichia coli O157:H7 along the production and supply chain of pork around Hubei Province of China. Microb Pathog 2018; 115:93-99. [DOI: 10.1016/j.micpath.2017.12.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/01/2017] [Accepted: 12/08/2017] [Indexed: 11/29/2022]
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18
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Lactobacillus rhamnosus L34 Attenuates Gut Translocation-Induced Bacterial Sepsis in Murine Models of Leaky Gut. Infect Immun 2017; 86:IAI.00700-17. [PMID: 29038123 DOI: 10.1128/iai.00700-17] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 10/04/2017] [Indexed: 01/17/2023] Open
Abstract
Gastrointestinal (GI) bacterial translocation in sepsis is well known, but the role of Lactobacillus species probiotics is still controversial. We evaluated the therapeutic effects of Lactobacillus rhamnosus L34 in a new sepsis model of oral administration of pathogenic bacteria with GI leakage induced by either an antibiotic cocktail (ATB) and/or dextran sulfate sodium (DSS). GI leakage with ATB, DSS, and DSS plus ATB (DSS+ATB) was demonstrated by fluorescein isothiocyanate (FITC)-dextran translocation to the circulation. The administration of pathogenic bacteria, either Klebsiella pneumoniae or Salmonella enterica serovar Typhimurium, enhanced translocation. Bacteremia was demonstrated within 24 h in 50 to 88% of mice with GI leakage plus the administration of pathogenic bacteria but not with GI leakage induction alone or bacterial gavage alone. Salmonella bacteremia was found in only 16 to 29% and 0% of mice with Salmonella and Klebsiella administrations, respectively. Klebsiella bacteremia was demonstrated in 25 to 33% and 10 to 16% of mice with Klebsiella and Salmonella administrations, respectively. Lactobacillus rhamnosus L34 attenuated GI leakage in these models, as shown by the reductions of FITC-dextran gut translocation, serum interleukin-6 (IL-6) levels, bacteremia, and sepsis mortality. The reduction in the amount of fecal Salmonella bacteria with Lactobacillus treatment was demonstrated. In addition, an anti-inflammatory effect of the conditioned medium from Lactobacillus rhamnosus L34 was also demonstrated by the attenuation of cytokine production in colonic epithelial cells in vitro In conclusion, Lactobacillus rhamnosus L34 attenuated the severity of symptoms in a murine sepsis model induced by GI leakage and the administration of pathogenic bacteria.
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19
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Han R, Xu L, Wang T, Liu B, Wang L. A Small Regulatory RNA Contributes to the Preferential Colonization of Escherichia coli O157:H7 in the Large Intestine in Response to a Low DNA Concentration. Front Microbiol 2017; 8:274. [PMID: 28289405 PMCID: PMC5326754 DOI: 10.3389/fmicb.2017.00274] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/09/2017] [Indexed: 11/13/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 (O157) is one of the most notorious human pathogens, causing severe disease in humans worldwide. O157 specifically colonizes the large intestine of mammals after passing through the small intestine, and this process is influenced by differential signals between the two regions. Small regulatory RNAs (sRNAs) are able to sense and respond to environmental changes and regulate diverse physiological processes in pathogenic bacteria. Although some sRNAs of O157 have been extensively investigated, whether these molecules can sense differences between the small and large intestine and influence the preferential colonization in the large intestine by O157 remains unknown. In this study, we identified a new sRNA, Esr055, in O157 which senses the low DNA concentration in the large intestine and contributes to the preferential colonization of the bacteria in this region. The number of O157 wild-type that adhered to the colon is 30.18 times higher than the number that adhered to the ileum of mice, while the number of the ΔEsr055 mutant that adhered to the colon decreased to 13.27 times higher than the number adhered to the ileum. Furthermore, we found that the expression of Esr055 is directly activated by the regulator, DeoR, and its expression is positively affected by DNA, which is significantly more abundant in the ileum than in the colon of mice. Additionally, combining the results of informatics predictions and transcriptomic analysis, we found that several virulence genes are up-regulated in the ΔEsr055 mutant and five candidate genes (z0568, z0974, z1356, z1926, and z5187) may be its direct targets.
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Affiliation(s)
- Runhua Han
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China
| | - Letian Xu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China
| | - Ting Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China
| | - Bin Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China
| | - Lei Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China; State Key Laboratory of Medicinal Chemical Biology, Nankai UniversityTianjin, China
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20
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Deng H, Li Z, Tan Y, Guo Z, Liu Y, Wang Y, Yuan Y, Yang R, Bi Y, Bai Y, Zhi F. A novel strain of Bacteroides fragilis enhances phagocytosis and polarises M1 macrophages. Sci Rep 2016; 6:29401. [PMID: 27381366 PMCID: PMC4933912 DOI: 10.1038/srep29401] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/20/2016] [Indexed: 02/07/2023] Open
Abstract
Commensal Bacteroides fragilis possesses immune-regulatory characteristics. Consequently, it has been proposed as a potential novel probiotic because of its therapeutic effects on immune imbalance, mental disorders and inflammatory diseases. Macrophages play a central role in the immune response, developing either a classical-M1 or an alternative-M2 phenotype after stimulation with various signals. The interactions between macrophages and B. fragilis, however, remain to be defined. Here, a new isolate of B. fragilis, ZY-312, was shown to possess admirable properties, including tolerance to simulated gastric fluid, intestinal fluid and ox bile, and good safety (MOI = 100, 200) and adherent ability (MOI = 100) to LoVo cells. Isolate ZY-312 cell lysate promoted phagocytosis of fluorescent microspheres and pathogenic bacteria in bone marrow-derived macrophage (BMDM) cells. Gene expression of IL-12, iNOS and IL-1β in BMDM cells was increased after treatment with ZY-312, indicating the induction of M1 macrophages, consistent with enhanced secretion of NO. Cell surface expression of CD80 and CD86 was also increased. This study is the first to demonstrate that B. fragilis enhances the phagocytic functions of macrophages, polarising them to an M1 phenotype. Our findings provide insight into the close relationship between B. fragilis and the innate immune system.
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Affiliation(s)
- Huimin Deng
- Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China
| | - Zhengchao Li
- Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China
| | - Yafang Tan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China
| | - Zhaobiao Guo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China
| | - Yangyang Liu
- Guangzhou ZhiYi biotechnology Co. Ltd. No. 3, Lanyue Road, International Business Incubator Building F, Guangzhou 510515, China
| | - Ye Wang
- Guangzhou ZhiYi biotechnology Co. Ltd. No. 3, Lanyue Road, International Business Incubator Building F, Guangzhou 510515, China
| | - Yuan Yuan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China
| | - Yujing Bi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, China
| | - Yang Bai
- Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Fachao Zhi
- Guangdong Provincial Key Laboratory of Gastroenterology, Inst. of Gastroenterology of Guangdong Province, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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21
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The Type Three Secretion System 2-Encoded Regulator EtrB Modulates Enterohemorrhagic Escherichia coli Virulence Gene Expression. Infect Immun 2016; 84:2555-65. [PMID: 27324484 DOI: 10.1128/iai.00407-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/15/2016] [Indexed: 11/20/2022] Open
Abstract
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a foodborne pathogen that causes bloody diarrhea and hemolytic uremic syndrome throughout the world. A defining feature of EHEC pathogenesis is the formation of attaching and effacing (AE) lesions on colonic epithelial cells. Most of the genes that code for AE lesion formation, including a type three secretion system (T3SS) and effectors, are carried within a chromosomal pathogenicity island called the locus of enterocyte effacement (LEE). In this study, we report that a putative regulator, which is encoded in the cryptic E. coli type three secretion system 2 (ETT2) locus and herein renamed EtrB, plays an important role in EHEC pathogenesis. The etrB gene is expressed as a monocistronic transcript, and EtrB autoregulates expression. We provide evidence that EtrB directly interacts with the ler regulatory region to activate LEE expression and promote AE lesion formation. Additionally, we mapped the EtrB regulatory circuit in EHEC to determine a global role for EtrB. EtrB is regulated by the transcription factor QseA, suggesting that these proteins comprise a regulatory circuit important for EHEC colonization of the gastrointestinal tract.
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22
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Wan B, Zhang Q, Tao J, Zhou A, Yao YF, Ni J. Global transcriptional regulation by H-NS and its biological influence on the virulence of Enterohemorrhagic Escherichia coli. Gene 2016; 588:115-23. [PMID: 27173635 DOI: 10.1016/j.gene.2016.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 04/30/2016] [Accepted: 05/04/2016] [Indexed: 10/21/2022]
Abstract
As a global transcriptional regulator, H-NS, the histone-like nucleoid-associated DNA-binding and bridging protein, plays a wide range of biological roles in bacteria. In order to determine the role of H-NS in regulating gene transcription and further find out the biological significance of this protein in Enterohemorrhagic Escherichia coli (EHEC), we conducted transcriptome analysis of hns mutant by RNA sequencing. A total of 983 genes were identified to be regulated by H-NS in EHEC. 213 and 770 genes were down-regulated and up-regulated in the deletion mutant of hns, respectively. Interestingly, 34 of 97 genes on virulence plasmid pO157 were down-regulated by H-NS. Although the deletion mutant of hns showed a decreased survival rate in macrophage compared with the wild type strain, it exhibited the higher ability to colonize mice gut and became more virulent to BALB/c mice. The BALB/c mice infected with the deletion mutant of hns showed a lower survival rate, and a higher bacterial burden in the gut, compared with those infected with wild type strain, especially when the gut microbiota was not disturbed by antibiotic administration. These findings suggest that H-NS plays an important role in virulence of EHEC by interacting with host gut microbiota.
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Affiliation(s)
- Baoshan Wan
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qiufen Zhang
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Tao
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | | | - Yu-Feng Yao
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jinjing Ni
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Abstract
The first major outbreaks caused by enterohemorrhagic Escherichia coli (EHEC) raised public and medical awareness of the risks associated with acquiring this potentially deadly infection. The widespread presence of these organisms in the environment, the severity of the clinical sequelae, and the lack of treatment options and effective preventive measures demand that we obtain a better understanding of how this group of organisms cause disease. Animal models allow study of the processes and factors that contribute to disease and, as such, form a valuable tool in the repertoire of infectious disease researchers. Yet despite more than 30 years of research, it seems that no single model host reproduces the full spectrum of clinical disease induced by EHEC in humans. In the first part of this review, a synopsis of what is known about EHEC infections is garnered from human outbreaks and biopsy specimens. The main features and limitations of EHEC infection models that are based on the three most commonly used species (pigs, rabbits, and mice) are described within a historical context. Recent advances are highlighted, and a brief overview of models based on other species is given. Finally, the impact of the host on moderating EHEC infection is considered in light of growing evidence for the need to consider the biology and virulence strategies of EHEC in the context of its niche within the intestine.
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Russo LM, Abdeltawab NF, O’Brien AD, Kotb M, Melton-Celsa AR. Mapping of genetic loci that modulate differential colonization by Escherichia coli O157:H7 TUV86-2 in advanced recombinant inbred BXD mice. BMC Genomics 2015; 16:947. [PMID: 26573818 PMCID: PMC4647490 DOI: 10.1186/s12864-015-2127-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/22/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Shiga toxin (Stx)-producing E. coli (STEC) are responsible for foodborne outbreaks that can result in severe human disease. During an outbreak, differential disease outcomes are observed after infection with the same STEC strain. One question of particular interest is why some infected people resolve infection after hemorrhagic colitis whereas others progress to the hemolytic uremic syndrome (HUS). Host age and infection dose have been implicated; however, these parameters do not appear to fully account for all of the observed variation in disease severity. Therefore, we hypothesized that additional host genetic factors may play a role in progression to HUS. METHODS AND RESULTS To mimic the genetic diversity in the human response to infection by STEC, we measured the capacity of an O157:H7 outbreak isolate to colonize mouse strains from the advanced recombinant inbred (ARI) BXD panel. We first infected the BXD parental strains C57BL/6 J (B6) and DBA/2 J (D2) with either 86-24 (Stx2a+) or TUV86-2, an Stx2a-negative isogenic mutant. Colonization levels were determined in an intact commensal flora (ICF) infection model. We found a significant difference in colonization levels between the parental B6 and D2 strains after infection with TUV86-2 but not with 86-24. This observation suggested that a host factor that may be masked by Stx2a affects O157:H7 colonization in some genetic backgrounds. We then determined the TUV86-2 colonization levels of 24 BXD strains in the ICF model. We identified several quantitative trait loci (QTL) associated with variation in colonization by correlation analyses. We found a highly significant QTL on proximal chromosome 9 (12.5-26.7 Mb) that strongly predicts variation in colonization levels and accounts for 15-20 % of variance. Linkage, polymorphism and co-citation analyses of the mapped region revealed 36 candidate genes within the QTL, and we identified five genes that are most likely responsible for the differential colonization. CONCLUSIONS The identification of the QTL on chromosome 9 supports our hypothesis that individual genetic makeup affects the level of colonization after infection with STEC O157:H7.
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Affiliation(s)
- Lisa M. Russo
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD USA
| | - Nourtan F. Abdeltawab
- University of Cincinnati College of Medicine & Cincinnati VA Medical Center, Cincinnati, OH USA ,Department Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Alison D. O’Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD USA
| | - Malak Kotb
- University of Cincinnati College of Medicine & Cincinnati VA Medical Center, Cincinnati, OH USA ,Department of Basic Biomedical Sciences, University of North Dakota, Grand Forks, ND USA
| | - Angela R. Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD USA
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DuVall JA, Borba JC, Shafagati N, Luzader D, Shukla N, Li J, Kehn-Hall K, Kendall MM, Feldman SH, Landers JP. Optical Imaging of Paramagnetic Bead-DNA Aggregation Inhibition Allows for Low Copy Number Detection of Infectious Pathogens. PLoS One 2015; 10:e0129830. [PMID: 26068926 PMCID: PMC4466016 DOI: 10.1371/journal.pone.0129830] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/13/2015] [Indexed: 11/18/2022] Open
Abstract
DNA-paramagnetic silica bead aggregation in a rotating magnetic field facilitates the quantification of DNA with femtogram sensitivity, but yields no sequence-specific information. Here we provide an original description of aggregation inhibition for the detection of DNA and RNA in a sequence-specific manner following loop-mediated isothermal amplification (LAMP). The fragments generated via LAMP fail to induce chaotrope-mediated bead aggregation; however, due to their ability to passivate the bead surface, they effectively inhibit bead aggregation by longer 'trigger' DNA. We demonstrate the utility of aggregation inhibition as a method for the detection of bacterial and viral pathogens with sensitivity that approaches single copies of the target. We successfully use this methodology for the detection of notable food-borne pathogens Escherichia coli O157:H7 and Salmonella enterica, as well as Rift Valley fever virus, a weaponizable virus of national security concern. We also show the concentration dependence of aggregation inhibition, suggesting the potential for quantification of target nucleic acid in clinical and environmental samples. Lastly, we demonstrate the ability to rapidly detect infectious pathogens by utilizing a cell phone and custom-written application (App), making this novel detection modality fully portable for point-of-care use.
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Affiliation(s)
- Jacquelyn A. DuVall
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States of America
| | - Juliane C. Borba
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States of America
| | - Nazly Shafagati
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, United States of America
| | - Deborah Luzader
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Nishant Shukla
- Department of Computer Science, University of Virginia, Charlottesville, VA, United States of America
| | - Jingyi Li
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States of America
| | - Kylene Kehn-Hall
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, United States of America
| | - Melissa M. Kendall
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Sanford H. Feldman
- Center for Comparative Medicine, University of Virginia, Charlottesville, VA, United States of America
| | - James P. Landers
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States of America
- Department of Mechanical Engineering, University of Virginia, Charlottesville, VA, United States of America
- Department of Pathology, University of Virginia, Charlottesville, VA, United States of America
- * E-mail:
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Iannino F, Herrmann CK, Roset MS, Briones G. Development of a dual vaccine for prevention of Brucella abortus infection and Escherichia coli O157:H7 intestinal colonization. Vaccine 2015; 33:2248-2253. [DOI: 10.1016/j.vaccine.2015.03.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 02/23/2015] [Accepted: 03/12/2015] [Indexed: 02/04/2023]
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Strain-dependent cellular immune responses in cattle following Escherichia coli O157:H7 colonization. Infect Immun 2014; 82:5117-31. [PMID: 25267838 DOI: 10.1128/iai.02462-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes hemorrhagic diarrhea and potentially fatal renal failure in humans. Ruminants are considered to be the primary reservoir for human infection. Vaccines that reduce shedding in cattle are only partially protective, and their underlying protective mechanisms are unknown. Studies investigating the response of cattle to colonization generally focus on humoral immunity, leaving the role of cellular immunity unclear. To inform future vaccine development, we studied the cellular immune responses of cattle during EHEC O157:H7 colonization. Calves were challenged either with a phage type 21/28 (PT21/28) strain possessing the Shiga toxin 2a (Stx2a) and Stx2c genes or with a PT32 strain possessing the Stx2c gene only. T-helper cell-associated transcripts at the terminal rectum were analyzed by reverse transcription-quantitative PCR (RT-qPCR). Induction of gamma interferon (IFN-γ) and T-bet was observed with peak expression of both genes at 7 days in PT32-challenged calves, while upregulation was delayed, peaking at 21 days, in PT21/28-challenged calves. Cells isolated from gastrointestinal lymph nodes demonstrated antigen-specific proliferation and IFN-γ release in response to type III secreted proteins (T3SPs); however, responsiveness was suppressed in cells isolated from PT32-challenged calves. Lymph node cells showed increased expression of the proliferation marker Ki67 in CD4(+) T cells from PT21/28-challenged calves, NK cells from PT32-challenged calves, and CD8(+) and γδ T cells from both PT21/28- and PT32-challenged calves following ex vivo restimulation with T3SPs. This study demonstrates that cattle mount cellular immune responses during colonization with EHEC O157:H7, the temporality of which is strain dependent, with further evidence of strain-specific immunomodulation.
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Enhanced virulence of the Escherichia coli O157:H7 spinach-associated outbreak strain in two animal models is associated with higher levels of Stx2 production after induction with ciprofloxacin. Infect Immun 2014; 82:4968-77. [PMID: 25225244 DOI: 10.1128/iai.02361-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) causes hemorrhagic colitis and the hemolytic-uremic syndrome (HUS). STEC strains may produce Stx1a and/or Stx2a or variants of either toxin. A 2006 spinach-associated outbreak of STEC O157:H7 resulted in higher hospitalization and HUS rates than previous STEC outbreaks. The spinach isolate, strain K3995, contains both stx2a and stx2c. We hypothesized that the enhanced virulence of K3995 reflects the combination of stx2 alleles (carried on lysogenic phages) and/or the amount of Stx2 made by that strain. We compared the virulence of K3995 to those of other O157:H7 isolates and an isogenic Stx2 mutant in rabbits and mice. We also measured the relative levels of Stx2 produced from those strains with or without induction of the stx-carrying phage. Some rabbits infected with K3995 exhibited intestinal pathology and succumbed to infection, while none of those infected with O157:H7 strain 2812 (Stx1a(+) Stx2a(+)) died or showed pathological signs. Rabbits infected with the isogenic Stx2a mutant K3995 stx2a::cat were not colonized as well as those infected with K3995 and exhibited no signs of disease. In the streptomycin-treated mouse model, more animals infected with K3995 died than did those infected with O157:H7 strain 86-24 (Stx2a(+)). Additionally, K3995 produced higher levels of total Stx2 and toxin phage DNA in cultures after phage induction than did 86-24. Our results demonstrate the greater virulence of K3995 compared to other O157:H7 strains in rabbits and mice. We conclude that this enhanced virulence is linked to higher levels of Stx2 expression as a consequence of increased phage induction.
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Eppinger M, Cebula TA. Future perspectives, applications and challenges of genomic epidemiology studies for food-borne pathogens: A case study of Enterohemorrhagic Escherichia coli (EHEC) of the O157:H7 serotype. Gut Microbes 2014; 6:194-201. [PMID: 25483335 PMCID: PMC4615391 DOI: 10.4161/19490976.2014.969979] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The shiga-toxin (Stx)-producing human pathogen Escherichia coli serotype O157:H7 is a highly pathogenic subgroup of Stx-producing E. coli (STEC) with food-borne etiology and bovine reservoir. Each year in the U. S., approximately 100,000 patients are infected with enterohemorrhagic E. coli (EHEC) of the O157:H7 serotype. This food-borne pathogen is a global public health threat responsible for widespread outbreaks of human disease. Since its initial discovery in 1982, O157:H7 has rapidly become the dominant EHEC serotype in North America. Hospitalization rates among patients as high as 50% have been reported for severe outbreaks of human disease. Symptoms of disease can rapidly deteriorate and progress to life-threatening complications such as Hemolytic Uremic Syndrome (HUS), the leading cause of kidney failure in children, or Hemorrhagic Colitis. In depth understanding of the genomic diversity that exists among currently circulating EHEC populations has broad applications for improved molecular-guided biosurveillance, outbreak preparedness, diagnostic risk assessment, and development of alternative toxin-suppressing therapeutics.
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Affiliation(s)
- Mark Eppinger
- Department of Biology; The University of Texas at San Antonio; San Antonio, TX, USA,South Texas Center For Emerging Infectious Diseases; The University of Texas at San Antonio; San Antonio, TX, USA,Correspondence to: Mark Eppinger;
| | - Thomas A Cebula
- Department of Biology; Johns Hopkins University; Baltimore, MD, USA,CosmosID; Fairfax, VA, USA
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Abstract
ABSTRACT
Shiga toxin-producing
Escherichia coli
(STEC) strains have been detected in a wide diversity of mammals, birds, fish, and several insects. Carriage by most animals is asymptomatic, thus allowing for dissemination of the bacterium in the environment without detection. Replication of the organism may occur in the gastrointestinal tract of some animals, notably ruminants. Carriage may also be passive or transient, without significant amplification of bacterial numbers while in the animal host. Animals may be classified as reservoir species, spillover hosts, or dead-end hosts. This classification is based on the animal's ability to (i) transmit STEC to other animal species and (ii) maintain STEC infection in the absence of continuous exposure. Animal reservoirs are able to maintain STEC infections in the absence of continuous STEC exposure and transmit infection to other species. Spillover hosts, although capable of transmitting STEC to other animals, are unable to maintain infection in the absence of repeated exposure. The large diversity of reservoir and spillover host species and the survival of the organism in environmental niches result in complex pathways of transmission that are difficult to interrupt.
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Comparative genomics and immunoinformatics approach for the identification of vaccine candidates for enterohemorrhagic Escherichia coli O157:H7. Infect Immun 2014; 82:2016-26. [PMID: 24595137 DOI: 10.1128/iai.01437-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains are major human food-borne pathogens, responsible for bloody diarrhea and hemolytic-uremic syndrome worldwide. Thus far, there is no vaccine for humans against EHEC infections. In this study, a comparative genomics analysis was performed to identify EHEC-specific antigens useful as potential vaccines. The genes present in both EHEC EDL933 and Sakai strains but absent in nonpathogenic E. coli K-12 and HS strains were subjected to an in silico analysis to identify secreted or surface-expressed proteins. We obtained a total of 65 gene-encoding protein candidates, which were subjected to immunoinformatics analysis. Our criteria of selection aided in categorizing the candidates as high, medium, and low priority. Three members of each group were randomly selected and cloned into pVAX-1. Candidates were pooled accordingly to their priority group and tested for immunogenicity against EHEC O157:H7 using a murine model of gastrointestinal infection. The high-priority (HP) pool, containing genes encoding a Lom-like protein (pVAX-31), a putative pilin subunit (pVAX-12), and a fragment of the type III secretion structural protein EscC (pVAX-56.2), was able to induce the production of EHEC IgG and sIgA in sera and feces. HP candidate-immunized mice displayed elevated levels of Th2 cytokines and diminished cecum colonization after wild-type challenge. Individually tested HP vaccine candidates showed that pVAX-12 and pVAX-56.2 significantly induced Th2 cytokines and production of fecal EHEC sIgA, with pVAX-56.2 reducing EHEC cecum colonization. We describe here a bioinformatics approach able to identify novel vaccine candidates potentially useful for preventing EHEC O157:H7 infections.
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Endersen L, O'Mahony J, Hill C, Ross RP, McAuliffe O, Coffey A. Phage Therapy in the Food Industry. Annu Rev Food Sci Technol 2014; 5:327-49. [DOI: 10.1146/annurev-food-030713-092415] [Citation(s) in RCA: 201] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Lorraine Endersen
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland; , ,
| | - Jim O'Mahony
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland; , ,
| | - Colin Hill
- Alimentary Pharmabiotic Centre and Department of Microbiology, University College Cork, Cork, Ireland;
| | - R. Paul Ross
- Alimentary Pharmabiotic Centre and Department of Microbiology, University College Cork, Cork, Ireland;
- Biotechnology Department, Moorepark Food Research Centre, Teagasc, Fermoy, Cork, Ireland; ,
| | - Olivia McAuliffe
- Biotechnology Department, Moorepark Food Research Centre, Teagasc, Fermoy, Cork, Ireland; ,
| | - Aidan Coffey
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland; , ,
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Oral intoxication of mice with Shiga toxin type 2a (Stx2a) and protection by anti-Stx2a monoclonal antibody 11E10. Infect Immun 2013; 82:1213-21. [PMID: 24379294 DOI: 10.1128/iai.01264-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) strains cause food-borne outbreaks of hemorrhagic colitis and, less commonly, a serious kidney-damaging sequela called the hemolytic uremic syndrome (HUS). Stx, the primary virulence factor expressed by STEC, is an AB5 toxin with two antigenically distinct forms, Stx1a and Stx2a. Although both toxins have similar biological activities, Stx2a is more frequently produced by STEC strains that cause HUS than is Stx1a. Here we asked whether Stx1a and Stx2a act differently when delivered orally by gavage. We found that Stx2a had a 50% lethal dose (LD50) of 2.9 μg, but no morbidity occurred after oral intoxication with up to 157 μg of Stx1a. We also compared several biochemical and histological parameters in mice intoxicated orally versus intraperitoneally with Stx2a. We discovered that both intoxication routes caused similar increases in serum creatinine and blood urea nitrogen, indicative of kidney damage, as well as electrolyte imbalances and weight loss in the animals. Furthermore, kidney sections from Stx2a-intoxicated mice revealed multifocal, acute tubular necrosis (ATN). Of particular note, we detected Stx2a in kidney sections from orally intoxicated mice in the same region as the epithelial cell type in which ATN was detected. Lastly, we showed reduced renal damage, as determined by renal biomarkers and histopathology, and full protection of orally intoxicated mice with monoclonal antibody (MAb) 11E10 directed against the toxin A subunit; conversely, an irrelevant MAb had no therapeutic effect. Orally intoxicated mice could be rescued by MAb 11E10 6 h but not 24 h after Stx2a delivery.
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Chen Y, Lee T, Hong W, Hsieh H, Chen M. Effects of Lactobacillus kefiranofaciens M1 isolated from kefir grains on enterohemorrhagic Escherichia coli infection using mouse and intestinal cell models. J Dairy Sci 2013; 96:7467-77. [DOI: 10.3168/jds.2013-7015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/31/2013] [Indexed: 12/12/2022]
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Nobles CL, Green SI, Maresso AW. A product of heme catabolism modulates bacterial function and survival. PLoS Pathog 2013; 9:e1003507. [PMID: 23935485 PMCID: PMC3723568 DOI: 10.1371/journal.ppat.1003507] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 06/04/2013] [Indexed: 11/25/2022] Open
Abstract
Bilirubin is the terminal metabolite in heme catabolism in mammals. After deposition into bile, bilirubin is released in large quantities into the mammalian gastrointestinal (GI) tract. We hypothesized that intestinal bilirubin may modulate the function of enteric bacteria. To test this hypothesis, we investigated the effect of bilirubin on two enteric pathogens; enterohemorrhagic E. coli (EHEC), a Gram-negative that causes life-threatening intestinal infections, and E. faecalis, a Gram-positive human commensal bacterium known to be an opportunistic pathogen with broad-spectrum antibiotic resistance. We demonstrate that bilirubin can protect EHEC from exogenous and host-generated reactive oxygen species (ROS) through the absorption of free radicals. In contrast, E. faecalis was highly susceptible to bilirubin, which causes significant membrane disruption and uncoupling of respiratory metabolism in this bacterium. Interestingly, similar results were observed for other Gram-positive bacteria, including B. cereus and S. aureus. A model is proposed whereby bilirubin places distinct selective pressure on enteric bacteria, with Gram-negative bacteria being protected from ROS (positive outcome) and Gram-positive bacteria being susceptible to membrane disruption (negative outcome). This work suggests bilirubin has differential but biologically relevant effects on bacteria and justifies additional efforts to determine the role of this neglected waste catabolite in disease processes, including animal models. Bilirubin is the terminal breakdown product of heme, which is deposited at high concentrations in the human intestine, where it can come into contact with host cells, the gastrointestinal (GI) microflora, and invading pathogens. Here, we report that bilirubin can act as a protectant for the Gram-negative bacterial pathogen E. coli O157:H7, which causes severe hemorrhagic diarrhea and life-threatening kidney damage. Paradoxically, bilirubin is highly toxic towards another enteric opportunistic pathogen, the Gram-positive bacterium E. faecalis. Whereas the protection of E. coli stems from the neutralization of host reactive oxygen species, bilirubin's toxicity toward E. faecalis is rooted in its lipophilic properties, which drives the rapid association of bilirubin with bacteria, leading to disrupted cell membranes and concomitant death. These results suggest small molecule metabolites can modulate bacterial communities in the intestine, a finding that may have important implications for diseases caused by enteric bacteria and disrupted flora.
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Affiliation(s)
- Christopher L. Nobles
- Baylor College of Medicine, Department of Molecular Virology and Microbiology, Houston, Texas, United States of America
| | - Sabrina I. Green
- Baylor College of Medicine, Department of Molecular Virology and Microbiology, Houston, Texas, United States of America
| | - Anthony W. Maresso
- Baylor College of Medicine, Department of Molecular Virology and Microbiology, Houston, Texas, United States of America
- * E-mail:
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Zumbrun SD, Melton-Celsa AR, Smith MA, Gilbreath JJ, Merrell DS, O’Brien AD. Dietary choice affects Shiga toxin-producing Escherichia coli (STEC) O157:H7 colonization and disease. Proc Natl Acad Sci U S A 2013; 110:E2126-33. [PMID: 23690602 PMCID: PMC3677460 DOI: 10.1073/pnas.1222014110] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The likelihood that a single individual infected with the Shiga toxin (Stx)-producing, food-borne pathogen Escherichia coli O157:H7 will develop a life-threatening sequela called the hemolytic uremic syndrome is unpredictable. We reasoned that conditions that enhance Stx binding and uptake within the gut after E. coli O157:H7 infection should result in greater disease severity. Because the receptor for Stx, globotriaosylceramide, is up-regulated in the presence of butyrate in vitro, we asked whether a high fiber diet (HFD) that reportedly enhances butyrate production by normal gut flora can influence the outcome of an E. coli O157 infection in mice. To address that question, groups of BALB/c mice were fed high (10%) or low (2%) fiber diets and infected with E. coli O157:H7 strain 86-24 (Stx2+). Mice fed an HFD exhibited a 10- to 100-fold increase in colonization, lost 15% more body weight, exhibited signs of morbidity, and had 25% greater mortality relative to the low fiber diet (LFD)-fed group. Additionally, sections of intestinal tissue from HFD-fed mice bound more Stx1 and expressed more globotriaosylceramide than did such sections from LFD-fed mice. Furthermore, the gut microbiota of HFD-fed mice compared with LFD-fed mice contained reduced levels of native Escherichia species, organisms that might protect the gut from colonization by incoming E. coli O157:H7. Taken together, these results suggest that susceptibility to infection and subsequent disease after ingestion of E. coli O157:H7 may depend, at least in part, on individual diet and/or the capacity of the commensal flora to produce butyrate.
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Affiliation(s)
- Steven D. Zumbrun
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | - Angela R. Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | - Mark A. Smith
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | - Jeremy J. Gilbreath
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | - D. Scott Merrell
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | - Alison D. O’Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
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Advances in the development of enterohemorrhagic Escherichia coli vaccines using murine models of infection. Vaccine 2013; 31:3229-35. [PMID: 23707170 DOI: 10.1016/j.vaccine.2013.05.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 01/22/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) strains are food borne pathogens with importance in public health. EHEC colonizes the large intestine and causes diarrhea, hemorrhagic colitis and in some cases, life-threatening hemolytic-uremic syndrome (HUS) due to the production of Shiga toxins (Stx). The lack of effective clinical treatment, sequelae after infection and mortality rate in humans supports the urgent need of prophylactic approaches, such as development of vaccines. Shedding from cattle, the main EHEC reservoir and considered the principal food contamination source, has prompted the development of licensed vaccines that reduce EHEC colonization in ruminants. Although murine models do not fully recapitulate human infection, they are commonly used to evaluate EHEC vaccines and the immune/protective responses elicited in the host. Mice susceptibility differs depending of the EHEC inoculums; displaying different mortality rates and Stx-mediated renal damage. Therefore, several experimental protocols have being pursued in this model to develop EHEC-specific vaccines. Recent candidate vaccines evaluated include those composed of virulence factors alone or as fused-subunits, DNA-based, attenuated bacteria and bacterial ghosts. In this review, we summarize progress in the design and testing of EHEC vaccines and the use of different strategies for the evaluation of novel EHEC vaccines in the murine model.
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Genomic analysis of bacteriophage PBECO4 infecting Escherichia coli O157:H7. Arch Virol 2013; 158:2399-403. [PMID: 23680925 DOI: 10.1007/s00705-013-1718-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 04/04/2013] [Indexed: 10/26/2022]
Abstract
Escherichia coli O157:H7 is a human pathogen. We isolated a novel bacteriophage infecting this bacterium from a sewage water treatment facility. Phage PBECO4 belongs to the family Myoviridae, having an isometric head and a contractile tail. It has a linear double-stranded DNA genome of 348,113 base pairs in length with a GC content of 34.09 %. Whole-genome sequencing revealed that PBECO4 is distantly related to enterobacteria phage vB_KleM_RaK2, with 10 % similarity, and Cronobacter phage vB_CsaM_GAP32 with 6 % similarity. Five hundred fifty-one putative open reading frames (ORFs) and six tRNA genes were found. Eight ORFs are related to genes encoding structural proteins, nine to DNA packaging, two to DNA lysis activity, and 42 to replication and regulation. Four hundred ninety ORFs have not been functionally annotated.
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Animal models for neonatal diseases in humans. Vaccine 2013; 31:2489-99. [DOI: 10.1016/j.vaccine.2012.11.089] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 11/20/2012] [Accepted: 11/28/2012] [Indexed: 01/09/2023]
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Virulence of the Shiga toxin type 2-expressing Escherichia coli O104:H4 German outbreak isolate in two animal models. Infect Immun 2013; 81:1562-74. [PMID: 23439303 DOI: 10.1128/iai.01310-12] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In May 2011, a large food-borne outbreak was traced to an unusual O104:H4 enteroaggregative Escherichia coli (EAEC) strain that produced Shiga toxin (Stx) type 2 (Stx2). We developed a mouse model to study the pathogenesis and treatment for this strain and examined the virulence of the isolate for Dutch belted rabbits. O104:H4 strain C227-11 was gavaged into C57BL/6 mice at 10(9) to 10(11) CFU/animal. The infected animals were then given water with ampicillin (Amp; 5 g/liter) ad libitum. The C227-11-infected, Amp-treated C57BL/6 mice exhibited both morbidity and mortality. Kidneys from mice infected with C227-11 showed acute tubular necrosis, a finding seen in mice infected with typical Stx-producing E. coli. We provided anti-Stx2 antibody after infection and found that all of the antibody-treated mice gained more weight than untreated mice and, in another study, that all of the antibody-treated animals lived, whereas 3/8 phosphate-buffered saline-treated mice died. We further compared the pathogenesis of C227-11 with that of an Stx-negative (Stx(-)) O104:H4 isolate, C734-09, and an Stx2(-) phage-cured derivative of C227-11. Whereas C227-11-infected animals lost weight or gained less weight over the course of infection and died, mice infected with either of the Stx(-) isolates did not lose weight and only one mouse died. When the Stx-positive (Stx(+)) and Stx2(-) O104:H4 strains were compared in rabbits, greater morbidity and mortality were observed in rabbits infected with the Stx2(+) isolates than the Stx2(-) isolates. In conclusion, we describe two animal models for EAEC pathogenesis, and these studies show that Stx2 is responsible for most of the virulence observed in C227-11-infected mice and rabbits.
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Mallick EM, McBee ME, Vanguri VK, Melton-Celsa AR, Schlieper K, Karalius BJ, O'Brien AD, Butterton JR, Leong JM, Schauer DB. A novel murine infection model for Shiga toxin-producing Escherichia coli. J Clin Invest 2012; 122:4012-24. [PMID: 23041631 DOI: 10.1172/jci62746] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 08/09/2012] [Indexed: 01/10/2023] Open
Abstract
Enterohemorrhagic E. coli (EHEC) is an important subset of Shiga toxin-producing (Stx-producing) E. coli (STEC), pathogens that have been implicated in outbreaks of food-borne illness and can cause intestinal and systemic disease, including severe renal damage. Upon attachment to intestinal epithelium, EHEC generates "attaching and effacing" (AE) lesions characterized by intimate attachment and actin rearrangement upon host cell binding. Stx produced in the gut transverses the intestinal epithelium, causing vascular damage that leads to systemic disease. Models of EHEC infection in conventional mice do not manifest key features of disease, such as AE lesions, intestinal damage, and systemic illness. In order to develop an infection model that better reflects the pathogenesis of this subset of STEC, we constructed an Stx-producing strain of Citrobacter rodentium, a murine AE pathogen that otherwise lacks Stx. Mice infected with Stx-producing C. rodentium developed AE lesions on the intestinal epithelium and Stx-dependent intestinal inflammatory damage. Further, the mice experienced lethal infection characterized by histopathological and functional kidney damage. The development of a murine model that encompasses AE lesion formation and Stx-mediated tissue damage will provide a new platform upon which to identify EHEC alterations of host epithelium that contribute to systemic disease.
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Affiliation(s)
- Emily M Mallick
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Zeinhom M, Tellez AM, Delcenserie V, El-Kholy AM, El-Shinawy SH, Griffiths MW. Yogurt containing bioactive molecules produced by Lactobacillus acidophilus La-5 exerts a protective effect against enterohemorrhagic Escherichia coli in mice. J Food Prot 2012; 75:1796-805. [PMID: 23043828 DOI: 10.4315/0362-028x.jfp-11-508] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
An active fraction extracted from Lactobacillus acidophilus La5 cell-free spent medium (LAla-5AF) was incorporated in a dairy matrix and tested to assess its antivirulent effect against enterohemorrhagic Escherichia coli (EHEC). Mice in experimental groups were fed for 4 days with yogurt supplemented with LAla-5AF. On the fifth day, mice were challenged with a single dose (10(7) CFU per mouse) of E. coli O157:H7. The clinical manifestations of the infection were significantly less severe in mice fed the yogurt supplemented with LAla-5AF. EHEC attachment and colonization was attenuated by LAla-5AF. Tumor necrosis factor alpha production was down-regulated, which might indicate a protective effect in the kidney during EHEC infection. To investigate the mechanisms associated with the in vivo effects observed, LAla-5AF was tested by reverse transcription real-time PCR to confirm its effects on the expression of several virulence genes of EHEC O157. The results showed that these fractions were able to down-regulate several virulence genes of EHEC, including stxB2, qseA, luxS, tir, ler, eaeA, and hlyB.
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Affiliation(s)
- Mohamed Zeinhom
- Food Hygiene & Control Department, Faculty of Veterinary Medicine, Beni-Suef University, Egypt
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Pacheco AR, Sperandio V. Shiga toxin in enterohemorrhagic E.coli: regulation and novel anti-virulence strategies. Front Cell Infect Microbiol 2012; 2:81. [PMID: 22919672 PMCID: PMC3417539 DOI: 10.3389/fcimb.2012.00081] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 05/23/2012] [Indexed: 01/09/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are responsible for major outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) throughout the world. The mortality associated with EHEC infections stems from the production and release of a potent Shiga toxin (Stx) by these bacteria. Stx induces cell death in endothelial cells, primarily in the urinary tract, causing HUS. Stx was first described in Shigella dysenteriae serotype I by Kiyoshi Shiga and was discovered later in EHEC. Multiple environmental cues regulate the expression of Stx, including temperature, growth phase, antibiotics, reactive oxygen species (ROS), and quorum sensing. Currently, there is no effective treatment or prophylaxis for HUS. Because antibiotics trigger Stx production and their use to treat EHEC infections is controversial, alternative therapeutic strategies have become the focus of intense research. One such strategy explores quorum sensing inhibitors as therapeutics. These inhibitors target quorum sensing regulation of Stx expression without interfering with bacterial growth, leading to the hypothesis that these inhibitors impose less selective pressure for bacteria to develop drug resistance. In this review, we discuss factors that regulate Stx production in EHEC, as well as novel strategies to prevent and/or minimize the development of HUS in infected subjects.
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Affiliation(s)
- Alline R Pacheco
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas TX, USA
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Contribution of urease to colonization by Shiga toxin-producing Escherichia coli. Infect Immun 2012; 80:2589-600. [PMID: 22665380 DOI: 10.1128/iai.00210-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen with a low infectious dose that colonizes the colon in humans and can cause severe clinical manifestations such as hemolytic-uremic syndrome. The urease enzyme, encoded in the STEC chromosome, has been demonstrated to act as a virulence factor in other bacterial pathogens. The NH(3) produced as urease hydrolyzes urea can aid in buffering bacteria in acidic environments as well as provide an easily assimilated source of nitrogen that bacteria can use to gain a metabolic advantage over intact microflora. Here, we explore the role of urease in STEC pathogenicity. The STEC urease enzyme exhibited maximum activity near neutral pH and during the stationary-growth phase. Experiments altering growth conditions performed with three phylogenetically distinct urease-positive strains demonstrated that the STEC ure gene cluster is inducible by neither urea nor pH but does respond to nitrogen availability. Quantitative reverse transcription-PCR (qRT-PCR) data indicate that nitrogen inhibits the transcriptional response. The deletion of the ure gene locus was constructed in STEC strain 88-0643, and the ure mutant was used with the wild-type strain in competition experiments in mouse models to examine the contribution of urease. The wild-type strain was twice as likely to survive passage through the acidic stomach and demonstrated an enhanced ability to colonize the intestinal tract compared to the ure mutant strain. These in vivo experiments reveal that, although the benefit STEC gains from urease expression is modest and not absolutely required for colonization, urease can contribute to the pathogenicity of STEC.
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Goodyear A, Bielefeldt-Ohmann H, Schweizer H, Dow S. Persistent gastric colonization with Burkholderia pseudomallei and dissemination from the gastrointestinal tract following mucosal inoculation of mice. PLoS One 2012; 7:e37324. [PMID: 22624016 PMCID: PMC3356274 DOI: 10.1371/journal.pone.0037324] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 04/18/2012] [Indexed: 12/26/2022] Open
Abstract
Melioidosis is a disease of humans caused by opportunistic infection with the soil and water bacterium Burkholderia pseudomallei. Melioidosis can manifest as an acute, overwhelming infection or as a chronic, recurrent infection. At present, it is not clear where B. pseudomallei resides in the mammalian host during the chronic, recurrent phase of infection. To address this question, we developed a mouse low-dose mucosal challenge model of chronic B. pseudomallei infection and investigated sites of bacterial persistence over 60 days. Sensitive culture techniques and selective media were used to quantitate bacterial burden in major organs, including the gastrointestinal (GI) tract. We found that the GI tract was the primary site of bacterial persistence during the chronic infection phase, and was the only site from which the organism could be consistently cultured during a 60-day infection period. The organism could be repeatedly recovered from all levels of the GI tract, and chronic infection was accompanied by sustained low-level fecal shedding. The stomach was identified as the primary site of GI colonization as determined by fluorescent in situ hybridization. Organisms in the stomach were associated with the gastric mucosal surface, and the propensity to colonize the gastric mucosa was observed with 4 different B. pseudomallei isolates. In contrast, B. pseudomallei organisms were present at low numbers within luminal contents in the small and large intestine and cecum relative to the stomach. Notably, inflammatory lesions were not detected in any GI tissue examined in chronically-infected mice. Only low-dose oral or intranasal inoculation led to GI colonization and development of chronic infection of the spleen and liver. Thus, we concluded that in a mouse model of melioidosis B. pseudomallei preferentially colonizes the stomach following oral inoculation, and that the chronically colonized GI tract likely serves as a reservoir for dissemination of infection to extra-intestinal sites.
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Affiliation(s)
- Andrew Goodyear
- Department of Microbiology, Immunology, and Pathology, Rocky Mountain Regional Center for Excellence for Biodefense and Emerging Infectious Diseases Research, Colorado State University, Fort Collins, Colorado, United States of America
| | | | - Herbert Schweizer
- Department of Microbiology, Immunology, and Pathology, Rocky Mountain Regional Center for Excellence for Biodefense and Emerging Infectious Diseases Research, Colorado State University, Fort Collins, Colorado, United States of America
| | - Steven Dow
- Department of Microbiology, Immunology, and Pathology, Rocky Mountain Regional Center for Excellence for Biodefense and Emerging Infectious Diseases Research, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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Mukhopadhyay S, Linstedt AD. Manganese blocks intracellular trafficking of Shiga toxin and protects against Shiga toxicosis. Science 2012; 335:332-5. [PMID: 22267811 PMCID: PMC5367627 DOI: 10.1126/science.1215930] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Infections with Shiga toxin (STx)-producing bacteria cause more than a million deaths each year and have no definitive treatment. To exert its cytotoxic effect, STx invades cells through retrograde membrane trafficking, escaping the lysosomal degradative pathway. We found that the widely available metal manganese (Mn(2+)) blocked endosome-to-Golgi trafficking of STx and caused its degradation in lysosomes. Mn(2+) targeted the cycling Golgi protein GPP130, which STx bound in control cells during sorting into Golgi-directed endosomal tubules that bypass lysosomes. In tissue culture cells, treatment with Mn(2+) yielded a protection factor of 3800 against STx-induced cell death. Furthermore, mice injected with nontoxic doses of Mn(2+) were completely resistant to a lethal STx challenge. Thus, Mn(2+) may represent a low-cost therapeutic agent for the treatment of STx infections.
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Affiliation(s)
- Somshuvra Mukhopadhyay
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Adam D. Linstedt
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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Hfq virulence regulation in enterohemorrhagic Escherichia coli O157:H7 strain 86-24. J Bacteriol 2011; 193:6843-51. [PMID: 21984790 DOI: 10.1128/jb.06141-11] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) causes bloody diarrhea and hemolytic-uremic syndrome. EHEC encodes the sRNA chaperone Hfq, which is important in posttranscriptional regulation. In EHEC strain EDL933, Hfq acts as a negative regulator of the locus of enterocyte effacement (LEE), which encodes most of the proteins involved in type III secretion and attaching and effacing (AE) lesions. Here, we deleted hfq in the EHEC strain 86-24 and compared global transcription profiles of the hfq mutant and wild-type (WT) strains in exponential growth phase. Deletion of hfq affected transcription of genes common to nonpathogenic and pathogenic strains of E. coli as well as pathogen-specific genes. Downregulated genes in the hfq mutant included ler, the transcriptional activator of all the LEE genes, as well as genes encoded in the LEE2 to -5 operons. Decreased expression of the LEE genes in the hfq mutant occurred at middle, late, and stationary growth phases. We also confirmed decreased regulation of the LEE genes by examining the proteins secreted and AE lesion formation by the hfq mutant and WT strains. Deletion of hfq also caused decreased expression of the two-component system qseBC, which is involved in interkingdom signaling and virulence gene regulation in EHEC, as well as an increase in expression of stx(2AB), which encodes the deadly Shiga toxin. Altogether, these data indicate that Hfq plays a regulatory role in EHEC 86-24 that is different from what has been reported for EHEC strain EDL933 and that the role of Hfq in EHEC virulence regulation extends beyond the LEE.
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48
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Mohawk KL, O'Brien AD. Mouse models of Escherichia coli O157:H7 infection and shiga toxin injection. J Biomed Biotechnol 2011; 2011:258185. [PMID: 21274267 PMCID: PMC3022220 DOI: 10.1155/2011/258185] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 11/03/2010] [Indexed: 01/19/2023] Open
Abstract
Escherichia coli O157:H7 has been responsible for multiple food- and waterborne outbreaks of diarrhea and/or hemorrhagic colitis (HC) worldwide. More importantly, a portion of E. coli O157:H7-infected individuals, particularly young children, develop a life-threatening sequela of infection called hemolytic uremic syndrome (HUS). Shiga toxin (Stx), a potent cytotoxin, is the major virulence factor linked to the presentation of both HC and HUS. Currently, treatment of E. coli O157:H7 and other Stx-producing E. coli (STEC) infections is limited to supportive care. To facilitate development of therapeutic strategies and vaccines for humans against these agents, animal models that mimic one or more aspect of STEC infection and disease are needed. In this paper, we focus on the characteristics of various mouse models that have been developed and that can be used to monitor STEC colonization, disease, pathology, or combinations of these features as well as the impact of Stx alone.
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Affiliation(s)
- Krystle L. Mohawk
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Alison D. O'Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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Melton-Celsa A, Mohawk K, Teel L, O’Brien A. Pathogenesis of Shiga-Toxin Producing Escherichia coli. Curr Top Microbiol Immunol 2011; 357:67-103. [DOI: 10.1007/82_2011_176] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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50
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Mohawk KL, Melton-Celsa AR, Robinson CM, O'Brien AD. Neutralizing antibodies to Shiga toxin type 2 (Stx2) reduce colonization of mice by Stx2-expressing Escherichia coli O157:H7. Vaccine 2010; 28:4777-85. [PMID: 20472033 DOI: 10.1016/j.vaccine.2010.04.099] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 04/22/2010] [Accepted: 04/28/2010] [Indexed: 11/17/2022]
Abstract
Previously, we showed that the Shiga toxin type 2 (Stx2)-expressing Escherichia coli O157:H7 strain 86-24 colonized mice better than did its isogenic stx(2) negative mutant. Here, we confirmed that finding by demonstrating that Stx2 given orally to mice increased the levels of the 86-24 stx(2) mutant shed in feces. Then we assessed the impact of Stx2-neutralizing antibodies, administered passively or generated by immunization with an Stx2 toxoid, on E. coli O157:H7 colonization of mice. We found that such antibodies reduced the E. coli O157:H7 burden in infected mice and, as anticipated, also protected them from weight loss and death.
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Affiliation(s)
- Krystle L Mohawk
- Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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