ETEC

ETEC causes diarrhea in children and tourists

Enterotoxigenic Escherichia coli (ETEC) are one of the most important causes of diarrhea in young children in low and middle-income countries (LMIC) as well as in travelers to these countries. The secreted heat-stable (ST) and heat-labile (LT) enterotoxins elicit net secretion of salts and water, resulting in diarrhea, in the most serious cases producing a profuse cholera-like condition. Being responsible for tens of thousands of child deaths in LMIC these bacteria can also inflict nutritional deficiencies during and after the infection.

Controlled human infection model

At the Department of Clinical Science, UiB and Haukeland University Hospital, our efforts have centered on developing a human challenge model with an ST-only ETEC strain and immunological assays to evaluate human immune responses to ETEC infection and future ETEC vaccine candidates. The model will be used to test protective efficacy of ST-based vaccine candidates; in other words whether volunteers who have been given the vaccine candidate are less affected than those given a placebo vaccine when they are later experimentally infected with an ETEC strain.

Until now, 60 volunteers have been experimentally infected with three different epidemiologically relevant ETEC strains. The project has attracted attention from local media and TV. Our project have shown the feasibility of conducting human challenge studies in Bergen, and an ETEC strain to test ST-based vaccine components has been identified. The ETEC strain TW11681 was tested in 9 of these volunteers and found to elicit abdominal symptoms in some volunteers, but hardly any diarrheal disease. However, the TW10722 strains was found to be SAFE and suitable as it could cause diarrheal illness in 79% of adult volunteers.

Immune responses against ETEC

Immunoassays to evaluate responses towards major ETEC antigens are being developed. The proliferation of ETEC during infection, and sublingual saliva as a noninvasive proxy for intestinal immune induction has been assessed. Further, studies on immune responses include mass cytometry (CyTOF) examination of peripheral blood immune cell subsets during infection, and multiplex bead-based assays that measure antibody responses to major ETEC virulence factors, also assessing the proportion of specific antibodies targeting glycosylated epitopes.

Cross-faculty and international collaboration

The ETEC research work performed in Bergen involves researchers at the University of Bergen, including from the Faculty of Medicine and the Faculty of Mathematics and Natural Sciences, from Haukeland University Hospital, and from NORCE Norwegian Research Centre AS. More information regarding the vaccine development arm of the project can be found here.

The research is done in collaboration with researchers at Norwegian Institute of Public Health in Oslo, the University of Maryland School of Medicine in Baltimore, University of Virginia in Charlottesville, Tulane University in New Orleans, Kansas State University in Manhattan, Indian Institute of Science in Bangalore and Institut Pasteur in Paris.

Funding

The ETEC research group has been made possible by grants from the Research Council of Norway, the European Union (through the STOPENTERICS network), EVI and PATH.

 

List of publications related to our work on development of a Controlled Human  ETEC challenge model:

Skrede S, Steinsland H, Sommerfelt H, Aase A, Brandtzaeg P, Langeland N, Cox RJ, Saevik M, Wallevik M, Skutlaberg DH, Tellevik MG, Sack DA, Nataro JP, Guttormsen AB. Experimental infection of healthy volunteers with enterotoxigenic Escherichia coli wild-type strain TW10598 in a hospital ward. BMC Infect Dis. 2014 Sep 4;14:482. doi: 10.1186/1471-2334-14-482. PMID: 25190096

Aase A, Sommerfelt H, Petersen LB, Bolstad M, Cox RJ, Langeland N, Guttormsen AB, Steinsland H, Skrede S, Brandtzaeg P. Salivary IgA from the sublingual compartment as a novel noninvasive proxy for intestinal immune induction. Mucosal Immunol. 2016 Jul;9(4):884-93. doi: 10.1038/mi.2015.107. Epub 2015 Oct 28. PMID: 26509875

Vedøy OB, Hanevik K, Sakkestad ST, Sommerfelt H, Steinsland H. Proliferation of enterotoxigenic Escherichia coli strain TW11681 in stools of experimentally infected human volunteers. Gut Pathog. 2018 Oct 16;10:46

Hanevik K, Chen WH, Talaat KR, Porter C, Bourgeois L. The way forward for ETEC controlled human infection models (CHIMs). Vaccine. 2019 Aug 7;37(34):4794-4799. (Review) Todnem Sakkestad S, Steinsland H, Skrede S, Kleppa E, Lillebø K, Sævik M, Søyland H, Rykkje Heien A, Gjerde Tellevik M, Barry EM, Sommerfelt H, Hanevik K. Experimental Infection of Human Volunteers with the Heat-Stable Enterotoxin-Producing ETEC Strain TW11681. Pathogens. 2019 Jun 22;8(2). pii: E84. Sakkestad ST, Skavland J, Hanevik K. Whole blood preservation methods alter chemokine receptor detection in mass cytometry experiments. J Immunol Methods. 2019 Oct 17:112673 Sakkestad ST, Steinsland H, Skrede S, Lillebø K, Skutlaberg DH, Guttormsen AB, Zavialov A, Paavilainen S, Søyland H, Sævik M, Heien AR, Tellevik MG, Barry E, Langeland N, Sommerfelt H, Hanevik K. A new human challenge model for testing heat-stable toxin-based vaccine candidates for enterotoxigenic Escherichia coli diarrhea - dose optimization, clinical outcomes, and CD4+ T cell responses. PLoS Negl Trop Dis. 2019 Oct 30;13(10):e0007823. Riaz S, Steinsland H, Hanevik K. Human Mucosal IgA Immune Responses against Enterotoxigenic Escherichia coli. Pathogens. 2020;9(9):E714. Cox E, Aloulou M, Fleckenstein JM, Schäffer C, Sjöling Å, Schüller S, Hanevik K, Devriendt B, Zhang W, Svennerholm AM, Dudley EG. The Intriguing Interaction of Escherichia coli with the Host Environment and Innovative Strategies to Interfere with Colonization: a Summary of the 2019 E. coli and Mucosal Immune System Meeting. Appl Environ Microbiol. 2020 Nov 24;86(24)

Riaz S, Steinsland H, Thorsing M, Andersen AZ, Boysen A, Hanevik K. Characterization of Glycosylation-Specific Systemic and Mucosal IgA Antibody Responses to Escherichia coli Mucinase YghJ (SslE). Front Immunol. 2021 Dec 17;12:760135.

Vedøy OB, Steinsland H, Sakkestad ST, Sommerfelt H, Hanevik K. Strong Association between Diarrhea and Concentration of Enterotoxigenic Escherichia coli Strain TW10722 in Stools of Experimentally Infected Volunteers. Pathogens. 2023 Feb 8;12(2):283

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 Apr 27:e2250254.

Brønstad I, von Volkmann HL, Sakkestad ST, Steinsland H, Hanevik K. Reduced Plasma Guanylin Levels Following Enterotoxigenic Escherichia coli-Induced Diarrhea. Microorganisms. 2023 Aug 3;11(8):1997

Baqar S, Bonavia A, Louis Bourgeois A, Campo JJ, Clifford A, Hanevik K, Hasso-Agopsowicz M, Hausdorff W, Kaminski R, MacLennan CA, Mantis N, Martin LB, Omore R, Pasetti M, Pavlinac P, Phalipon A, Poly F, Porter C, Ramasamy MN, Rogawski McQuade ET, Sztein MB, Walker R. The 2022 Vaccines Against Shigella and Enterotoxigenic Escherichia coli (VASE) Conference: Summary of breakout workshops. Vaccine. 2024 Mar 7;42(7):1445-1453.

Riaz SM, Hanevik K, Helgeland L, Sviland L, Hunter RL, Mustafa T. Novel Insights into the Pathogenesis of Human Post-Primary Tuberculosis from Archival Material of the Pre-Antibiotic Era, 1931-1947. Pathogens. 2023 Dec 7;12(12):1426.

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 Jan-Dec;16(1):2295891.                                                                                                                      

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 Mar 2;213(1):2.