Comparison of clinical and immunological findings in gnotobiotic piglets infected with Escherichia coli O104:H4 outbreak strain and EHEC O157:H7

Bettina Wöchtl; Florian Gunzer; Wilhelm Gerner; Hagen Gasse; Michaela Koch; Zoltán Bagó; Martin Ganter; Herbert Weissenböck; Nora Dinhopl; Sina M Coldewey; Alexandra von Altrock; Karl-Heinz Waldmann; Armin Saalmüller; Kurt Zimmermann; Jörg Steinmann; Jan Kehrmann; Ludger Klein-Hitpass; Jochen Blom; Ralf Ehricht; Ines Engelmann; Isabel Hennig-Pauka

doi:10.1186/s13099-017-0179-8

Comparison of clinical and immunological findings in gnotobiotic piglets infected with Escherichia coli O104:H4 outbreak strain and EHEC O157:H7

Gut Pathog. 2017 May 25:9:30. doi: 10.1186/s13099-017-0179-8. eCollection 2017.

Authors

Bettina Wöchtl¹, Florian Gunzer², Wilhelm Gerner³, Hagen Gasse⁴, Michaela Koch¹, Zoltán Bagó⁵, Martin Ganter⁶, Herbert Weissenböck⁷, Nora Dinhopl⁷, Sina M Coldewey^{8

9}, Alexandra von Altrock⁶, Karl-Heinz Waldmann⁶, Armin Saalmüller³, Kurt Zimmermann¹⁰, Jörg Steinmann¹¹, Jan Kehrmann¹¹, Ludger Klein-Hitpass¹², Jochen Blom¹³, Ralf Ehricht¹⁴, Ines Engelmann¹⁴, Isabel Hennig-Pauka¹

Affiliations

¹ University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1220 Vienna, Austria.
² Institute of Medical Microbiology and Hygiene, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
³ Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1220 Vienna, Austria.
⁴ Institute of Anatomy, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany.
⁵ Institute for Veterinary Disease Control Mödling, Austrian Agency for Health and Food Safety, Robert-Koch-Gasse 17, 2340 Mödling, Austria.
⁶ Clinic for Swine, Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany.
⁷ Institute for Pathology and Forensic Veterinary Medicine, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1220 Vienna, Austria.
⁸ Department of Anaesthesiology and Intensive Care Medicine, University Hospital Jena, Am Klinikum 1, 07747 Jena, Germany.
⁹ Centre for Innovation Competence (ZIK) Septomics, University Hospital Jena, Albert-Einstein-Strasse 10, 07745 Jena, Germany.
¹⁰ SymbioPharm GmbH, Auf den Lüppen 10, 35745 Herborn, Germany.
¹¹ Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147 Essen, Germany.
¹² Institute of Cell Biology, Medical Faculty, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147 Essen, Germany.
¹³ Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany.
¹⁴ Alere Technologies GmbH, Löbstedter Straße 103-105, 07749 Jena, Germany.

Abstract

Background: Shiga toxin (Stx) producing Escherichia coli (E. coli) (STEC) is the most frequent cause of diarrhoea-positive haemolytic uraemic syndrome (D + HUS) in humans. In 2011, a huge outbreak with an STEC O104:H4 strain in Germany highlighted the limited possibilities for causative treatment of this syndrome. The responsible STEC strain was found to combine Stx production with adherence mechanisms normally found in enteroaggregative E. coli (EAEC). Pathotypes of E. coli evolve and can exhibit different adhesion mechanisms. It has been shown previously that neonatal gnotobiotic piglets are susceptible for infection with STEC, such as STEC O157:H7 as well as for EAEC, which are considered to be the phylogenetic origin of E. coli O104:H4. This study was designed to characterise the host response to infection with the STEC O104:H4 outbreak strain in comparison to an STEC O157:H7 isolate by evaluating clinical parameters (scoring) and markers of organ dysfunction (biochemistry), as well as immunological (flow cytometry, assessment of cytokines/chemokines and acute phase proteins) and histological alterations (light- and electron microscopy) in a gnotobiotic piglet model of haemolytic uraemic syndrome.

Results: We observed severe clinical symptoms, such as diarrhoea, dehydration and neurological disorders as well as attaching-and-effacing lesions (A/E) in the colon in STEC O157:H7 infected piglets. In contrast, STEC O104:H4 challenged animals exhibited only mild clinical symptoms including diarrhoea and dehydration and HUS-specific/severe histopathological, haematological and biochemical alterations were only inconsistently presented by individual piglets. A specific adherence phenotype of STEC O104:H4 could not be observed. Flow cytometric analyses of lymphocytes derived from infected animals revealed an increase of natural killer cells (NK cells) during the course of infection revealing a potential role of this subset in the anti-bacterial activity in STEC disease.

Conclusions: Unexpectedly, E. coli O104:H4 infection caused only mild symptoms and minor changes in histology and blood parameters in piglets. Outcome of the infection trial does not reflect E. coli O104:H4 associated human disease as observed during the outbreak in 2011. The potential role of cells of the innate immune system for STEC related disease pathogenesis should be further elucidated.

Keywords: E. coli O104:H4; E. coli O157:H7; Enteroaggregative E. coli; Enterohaemmorrhagic E. coli; Gnotobiotic piglets; Haemolytic uraemic syndrome (HUS); Shiga toxin; Swine.