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Rachmühl C, Lacroix C, Ferragamo A, Giorgetti A, Stoffel NU, Zimmermann MB, Brittenham GM, Geirnaert A. Galacto-oligosaccharides alone and combined with lactoferrin impact the Kenyan infant gut microbiota and epithelial barrier integrity during iron supplementation in vitro. MICROBIOME RESEARCH REPORTS 2024; 4:9. [PMID: 40207277 PMCID: PMC11978484 DOI: 10.20517/mrr.2024.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 11/20/2024] [Accepted: 12/17/2024] [Indexed: 04/11/2025]
Abstract
Aim: Iron supplementation to African weaning infants was associated with increased enteropathogen levels. While cohort studies demonstrated that specific prebiotics inhibit enteropathogens during iron supplementation, their mechanisms remain elusive. Here, we investigated the in vitro impact of galacto-oligosaccharides (GOS) and iron-sequestering bovine lactoferrin (bLF) alone and combined on the gut microbiota of Kenyan infants during low-dose iron supplementation. Methods: Different doses of iron, GOS, and bLF were first screened during batch fermentations (n = 3), and the effect of these factors was studied on microbiota community structure and activity in the new Kenyan infant continuous intestinal PolyFermS model. The impact of different fermentation treatments on barrier integrity, enterotoxigenic Escherichia coli (ETEC) infection, and inflammatory response was assessed using a transwell co-culture of epithelial and immune cells. Results: A dose-dependent increase in short-chain fatty acid (SCFA) production, Bifidobacterium and Lactobacillus/Leuconostoc/Pediococcus (LLP) growth was detected with GOS alone and combined with bLF during iron supplementation in batches. This was confirmed in the continuous PolyFermS model, which also showed a treatment-induced inhibition of opportunistic pathogens C. difficile and C. perfringens. In all tests, supplementation of iron alone and combined with bLF did not have a significant effect on microbiota composition and activity. We observed a strengthening of the epithelial barrier and a decrease in cell death and pro-inflammatory response during ETEC infection with microbiota fermentation supernatants from iron + GOS, iron + bLF, and iron + GOS + bLF treatments compared to iron alone. Conclusion: Overall, beneficial effects on infant gut microbiota were shown using advanced in vitro models for GOS alone and combined with bLF during low-dose iron supplementation.
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Affiliation(s)
- Carole Rachmühl
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
| | - Christophe Lacroix
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
| | - Adele Ferragamo
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
- Current address: Clean Mouse Facility, Experimental Animal Center, Department for Biomedical Research, University of Bern, Bern 3008, Switzerland
| | - Ambra Giorgetti
- Laboratory of Human Nutrition, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
| | - Nicole U. Stoffel
- Laboratory of Human Nutrition, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
| | - Michael B. Zimmermann
- Medical Research Council Translational Immune Discovery Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Gary M. Brittenham
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Annelies Geirnaert
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
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von Mentzer A, Svennerholm AM. Colonization factors of human and animal-specific enterotoxigenic Escherichia coli (ETEC). Trends Microbiol 2024; 32:448-464. [PMID: 38052687 DOI: 10.1016/j.tim.2023.11.001] [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: 07/11/2023] [Revised: 11/01/2023] [Accepted: 11/07/2023] [Indexed: 12/07/2023]
Abstract
Colonization factors (CFs) are major virulence factors of enterotoxigenic Escherichia coli (ETEC). This pathogen is among the most common causes of bacterial diarrhea in children in low- and middle-income countries, travelers, and livestock. CFs are major candidate antigens in vaccines under development as preventive measures against ETEC infections in humans and livestock. Recent molecular studies have indicated that newly identified CFs on human ETEC are closely related to animal ETEC CFs. Increased knowledge of pathogenic mechanisms, immunogenicity, regulation, and expression of ETEC CFs, as well as the possible spread of animal ETEC to humans, may facilitate the future development of ETEC vaccines for humans and animals. Here, we present an updated review of CFs in ETEC.
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Affiliation(s)
- Astrid von Mentzer
- Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Sweden; Wellcome Sanger Institute, Hinxton, UK.
| | - Ann-Mari Svennerholm
- Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Sweden
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Hollifield IE, Motyka NI, Stewart SR, Blyth MD, Fernando KA, Clement KL, Bitoun JP. Heat-Stable Enterotoxin Secretions Assessed via ICP-MS Reveal Iron-Mediated Regulation of Virulence in CFA/I- and CS6-Expressing ETEC Isolates. Cells 2023; 12:567. [PMID: 36831233 PMCID: PMC9954033 DOI: 10.3390/cells12040567] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/11/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) are a significant cause of childhood diarrhea in low-resource settings. ETEC are defined by the production of heat-stable enterotoxin (ST) and/or heat-labile enterotoxin (LT), which alter intracellular cyclic nucleotide signaling and cause the secretion of water and electrolytes into the intestinal lumen. ETEC take cues from chemicals (e.g., glycans, bile salts, and solutes) that may be liberated following enterotoxin activity to recognize entrance into the host. ETEC then alter the expression of surface adhesins called colonization factors (CFs) to attach to the intestinal epithelium, proliferate, and cause disease. Here, we used an in vivo model of oral ST intoxication to determine its impact on luminal ion concentrations via ICP-MS. We also used functional assays, including Western blots, qPCR, and toxin activity assays, to assess the impact of luminal ion flux on CF and toxin expression. Finally, we assessed ETEC strains with CFs CFA/I or CS6 in a streptomycin mouse model of ETEC colonization. ST causes rapid and significant increases in luminal chloride but significant decreases in luminal magnesium and iron. We confirmed that increased sodium chloride suppresses CFA/I production in ETEC H10407 but does not affect CS6 production in ETEC 214-4. CFA/I production in ETEC H10407 is increased when magnesium becomes limiting, although it does not affect CS6 production in ETEC 214-4. Iron restriction via deferoxamine induces CFA/I expression in ETEC H10407 but not CS6 expression in ETEC 214-4. We demonstrate that ST production is suppressed via iron restriction in H10407, 214-4, and over 50 other ETEC clinical isolates. Lastly, we demonstrate that the iron restriction of mice using oral deferoxamine pre-treatment extends the duration of ETEC H10407 (CFA/I+) fecal shedding while accelerating ETEC 214-4 (CS6+) fecal shedding. Combined, these data suggest that enterotoxins modulate luminal ion flux to influence ETEC virulence including toxin and CF production.
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Affiliation(s)
| | | | | | | | | | | | - Jacob P. Bitoun
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
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Djoko K, Cavet J. Perspectives on Metals in Microbiology. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35786425 DOI: 10.1099/mic.0.001215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Karrera Djoko
- Department of Biosciences, Durham University, Durham, UK
| | - Jennifer Cavet
- School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
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