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Rim S, Vedøy OB, Brønstad I, McCann A, Meyer K, Steinsland H, Hanevik K. Inflammation, the kynurenines, and mucosal injury during human experimental enterotoxigenic Escherichia coli infection. Med Microbiol Immunol 2024; 213:2. [PMID: 38430452 PMCID: PMC10908629 DOI: 10.1007/s00430-024-00786-z] [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: 07/24/2023] [Accepted: 12/29/2023] [Indexed: 03/03/2024]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea in children and travelers, especially in low- and middle-income countries. ETEC is a non-invasive gut pathogen colonizing the small intestinal wall before secreting diarrhea-inducing enterotoxins. We sought to investigate the impact of ETEC infection on local and systemic host defenses by examining plasma markers of inflammation and mucosal injury as well as kynurenine pathway metabolites. Plasma samples from 21 volunteers experimentally infected with ETEC were collected before and 1, 2, 3, and 7 days after ingesting the ETEC dose, and grouped based on the level of intestinal ETEC proliferation: 14 volunteers experienced substantial proliferation (SP) and 7 had low proliferation (LP). Plasma markers of inflammation, kynurenine pathway metabolites, and related cofactors (vitamins B2 and B6) were quantified using targeted mass spectrometry, whereas ELISA was used to quantify the mucosal injury markers, regenerating islet-derived protein 3A (Reg3a), and intestinal fatty acid-binding protein 2 (iFABP). We observed increased concentrations of plasma C-reactive protein (CRP), serum amyloid A (SAA), neopterin, kynurenine/tryptophan ratio (KTR), and Reg3a in the SP group following dose ingestion. Vitamin B6 forms, pyridoxal 5'-phosphate and pyridoxal, decreased over time in the SP group. CRP, SAA, and pyridoxic acid ratio correlated with ETEC proliferation levels. The changes following experimental ETEC infection indicate that ETEC, despite causing a non-invasive infection, induces systemic inflammation and mucosal injury when proliferating substantially, even in cases without diarrhea. It is conceivable that ETEC infections, especially when repeated, contribute to negative health impacts on children in ETEC endemic areas.
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Affiliation(s)
- Sehee Rim
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway.
| | - Oda Barth Vedøy
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Ingeborg Brønstad
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | | | | | - Hans Steinsland
- Department of Global Public Health and Primary Care, Faculty of Medicine, Centre for Intervention Science in Maternal and Child Health, Centre for International Health, University of Bergen, Bergen, Norway
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
- Department of Medicine, National Center for Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
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Kjellin J, Lee D, Steinsland H, Dwane R, Barth Vedoy O, Hanevik K, Koskiniemi S. Colicins and T6SS-based competition systems enhance enterotoxigenic E. coli (ETEC) competitiveness. Gut Microbes 2024; 16:2295891. [PMID: 38149626 PMCID: PMC10761095 DOI: 10.1080/19490976.2023.2295891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 12/13/2023] [Indexed: 12/28/2023] Open
Abstract
Diarrheal diseases are still a significant problem for humankind, causing approximately half a million deaths annually. To cause diarrhea, enteric bacterial pathogens must first colonize the gut, which is a niche occupied by the normal bacterial microbiota. Therefore, the ability of pathogenic bacteria to inhibit the growth of other bacteria can facilitate the colonization process. Although enterotoxigenic Escherichia coli (ETEC) is one of the major causative agents of diarrheal diseases, little is known about the competition systems found in and used by ETEC and how they contribute to the ability of ETEC to colonize a host. Here, we collected a set of 94 fully assembled ETEC genomes by performing whole-genome sequencing and mining the NCBI RefSeq database. Using this set, we performed a comprehensive search for delivered bacterial toxins and investigated how these toxins contribute to ETEC competitiveness in vitro. We found that type VI secretion systems (T6SS) were widespread among ETEC (n = 47). In addition, several closely related ETEC strains were found to encode Colicin Ia and T6SS (n = 8). These toxins provide ETEC competitive advantages during in vitro competition against other E. coli, suggesting that the role of T6SS as well as colicins in ETEC biology has until now been underappreciated.
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Affiliation(s)
- Jonas Kjellin
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Danna Lee
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Hans Steinsland
- CISMAC, Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Rachel Dwane
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Oda Barth Vedoy
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, Bergen, Norway
- National centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Sanna Koskiniemi
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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Brønstad I, von Volkmann HL, Sakkestad ST, Steinsland H, Hanevik K. Reduced Plasma Guanylin Levels Following Enterotoxigenic Escherichia coli-Induced Diarrhea. Microorganisms 2023; 11:1997. [PMID: 37630557 PMCID: PMC10458898 DOI: 10.3390/microorganisms11081997] [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: 06/25/2023] [Revised: 07/20/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023] Open
Abstract
The intestinal peptide hormones guanylin (GN) and uroguanylin (UGN) interact with the epithelial cell receptor guanylate cyclase C to regulate fluid homeostasis. Some enterotoxigenic Escherichia coli (ETEC) produce heat-stable enterotoxin (ST), which induces diarrhea by mimicking GN and UGN. Plasma concentrations of prohormones of GN (proGN) and UGN (proUGN) are reportedly decreased during chronic diarrheal diseases. Here we investigate whether prohormone concentrations also drop during acute diarrhea caused by ST-producing ETEC strains TW10722 and TW11681. Twenty-one volunteers were experimentally infected with ETEC. Blood (n = 21) and urine (n = 9) specimens were obtained immediately before and 1, 2, 3, and 7 days after ETEC ingestion. Concentrations of proGN and proUGN were measured by ELISA. Urine electrolyte concentrations were measured by photometry and mass spectrometry. Ten volunteers developed diarrhea (D group), and eleven did not (ND group). In the D group, plasma proGN, but not proUGN, concentrations were substantially reduced on days 2 and 3, coinciding with one day after diarrhea onset. No changes were seen in the ND group. ETEC diarrhea also seemed to affect diuresis, the zinc/creatinine ratio, and sodium and chloride secretion levels in urine. ETEC-induced diarrhea causes a reduction in plasma proGN and could potentially be a useful marker for intestinal isotonic fluid loss.
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Affiliation(s)
- Ingeborg Brønstad
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, 5021 Bergen, Norway; (I.B.); (H.L.v.V.)
- Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| | - Hilde Løland von Volkmann
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, 5021 Bergen, Norway; (I.B.); (H.L.v.V.)
- Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| | - Sunniva Todnem Sakkestad
- Department of Clinical Science, University of Bergen, 5021 Bergen, Norway;
- National Center for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| | - Hans Steinsland
- Centre for Intervention Science in Maternal and Child Health (CISMAC), Centre of International Health, Department of Global Public Health and Primary Care, University of Bergen, 5020 Bergen, Norway;
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, 5021 Bergen, Norway;
- National Center for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
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Rim S, Sakkestad ST, Zhou F, Gullaksen SE, Skavland J, Chauhan SK, Steinsland H, Hanevik K. Dynamics of circulating lymphocytes responding to human experimental enterotoxigenic Escherichia coli infection. Eur J Immunol 2023; 53:e2250254. [PMID: 37102399 DOI: 10.1002/eji.202250254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/11/2023] [Accepted: 04/24/2023] [Indexed: 04/28/2023]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is an important cause of children's and travelers' diarrhea, with no licensed vaccine. This study aimed to explore the role of cellular immunity in protection against human ETEC infection. Nine volunteers were experimentally infected with ETEC, of which six developed diarrhea. Lymphocytes were collected from peripheral blood buffy coats, before and 3, 5, 6, 7, 10, and 28 days after dose ingestion, and 34 phenotypic and functional markers were examined by mass cytometry. Thirty-three cell populations, derived by manually merging 139 cell clusters from the X-shift unsupervised clustering algorithm, were analyzed. Initially, the diarrhea group responded with increased CD56dim CD16+ natural killer cells, dendritic cells tended to rise, and mucosal-associated invariant T cells decreased. On day 5-7, an increase in plasmablasts was paralleled by a consistent rise in CD4+ Th17-like effector memory and regulatory cell subsets. CD4+ Th17-like central memory cells peaked on day 10. All Th17-like cell populations showed increased expression of activation, gut-homing, and proliferation markers. Interestingly, in the nondiarrhea group, these same CD4+ Th17-like cell populations expanded earlier, normalizing around day 7. Earlier development of these CD4+ Th17-like cell populations in the nondiarrhea group may suggest a recall response and a potential role in controlling ETEC infections.
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Affiliation(s)
- Sehee Rim
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Sunniva T Sakkestad
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Fan Zhou
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Stein-Erik Gullaksen
- Department of Clinical Science, Centre of Cancer Biomarkers (CCBIO), University of Bergen, Bergen, Norway
- Hematology Section, Department of Internal Medicine, Helse Bergen, Bergen, Norway
| | - Jørn Skavland
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Sudhir K Chauhan
- Division of Cancer Medicine, Department of Cancer Immunology, Oslo University Hospital, Oslo, Norway
| | - Hans Steinsland
- Department of Global Public Health and Primary Care, Faculty of Medicine, Centre for Intervention Science in Maternal and Child Health (CISMAC), Centre for International Health, University of Bergen, Bergen, Norway
- Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
- Department of Medicine, Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
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