Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya

Enterotoxigenic <i>Escherichia coli</i> (ETEC) is a significant cause of diarrhoea in livestock and humans. The epidemiology of ETEC in animals remains understudied, prompting an investigation into the virulence factors and associated adhesins of ETEC in livestock from Western Kenya. Also, there is...

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Main Authors: Njoroge, Samuel M., Kulohoma, B.W., Falzon, L.C., Kamanu, T.K., Momanyi, Kelvin, Muinde, Patrick, Murungi, Maurice K., Ogendo, A., Ogola, J., Wambua, Lillian, Kang'ethe, Erastus, Rushton, J., Woolhouse, M., Thomson, N.R., Kariuki, S., Mentzer, A. von, Fèvre, Eric M.
Format: Journal Article
Language:Inglés
Published: Microbiology Society 2025
Subjects:
Online Access:https://hdl.handle.net/10568/176868
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author Njoroge, Samuel M.
Kulohoma, B.W.
Falzon, L.C.
Kamanu, T.K.
Momanyi, Kelvin
Muinde, Patrick
Murungi, Maurice K.
Ogendo, A.
Ogola, J.
Wambua, Lillian
Kang'ethe, Erastus
Rushton, J.
Woolhouse, M.
Thomson, N.R.
Kariuki, S.
Mentzer, A. von
Fèvre, Eric M.
author_browse Falzon, L.C.
Fèvre, Eric M.
Kamanu, T.K.
Kang'ethe, Erastus
Kariuki, S.
Kulohoma, B.W.
Mentzer, A. von
Momanyi, Kelvin
Muinde, Patrick
Murungi, Maurice K.
Njoroge, Samuel M.
Ogendo, A.
Ogola, J.
Rushton, J.
Thomson, N.R.
Wambua, Lillian
Woolhouse, M.
author_facet Njoroge, Samuel M.
Kulohoma, B.W.
Falzon, L.C.
Kamanu, T.K.
Momanyi, Kelvin
Muinde, Patrick
Murungi, Maurice K.
Ogendo, A.
Ogola, J.
Wambua, Lillian
Kang'ethe, Erastus
Rushton, J.
Woolhouse, M.
Thomson, N.R.
Kariuki, S.
Mentzer, A. von
Fèvre, Eric M.
author_sort Njoroge, Samuel M.
collection Repository of Agricultural Research Outputs (CGSpace)
description Enterotoxigenic <i>Escherichia coli</i> (ETEC) is a significant cause of diarrhoea in livestock and humans. The epidemiology of ETEC in animals remains understudied, prompting an investigation into the virulence factors and associated adhesins of ETEC in livestock from Western Kenya. Also, there is limited evidence supporting the role of livestock as possible zoonotic reservoirs for ETEC. ETEC strains harbour colonization factors/adhesins and enterotoxins, with animal ETECs exhibiting various adhesins (F4, F5, F6, F17, F18 and F41). Enterotoxins include heat-labile (LT) and heat-stable (ST) toxins and are further divided into LT-I and LT-II and STa and STb, respectively. Additional toxin combinations occur, with ETEC and Shiga toxin-producing <i>E. coli</i> (STEC) hybrids garnering public health significance. Here, we analysed faecal and mesenteric lymph node samples from diverse livestock across three Western Kenyan counties (Busia, Bungoma and Kakamega), using whole-genome sequencing. <i>In silico</i> screening determined the presence of AB5 and A2B5-like toxin genes, including cytolethal distending toxin (<i>cdt</i>ABC) along with associated adhesins. To broaden the screening panel, adhesin genes identified were further characterized to identify both known and novel alleles, particularly focusing on human-ETEC colonization factors. Two <i>estA</i> alleles (<i>estA</i>-4-06, <i>estA</i>-6-02) and six <i>eltAB</i>-II toxin alleles (<i>eltAB</i>-II-a2-01, <i>eltAB</i>-II-a3-01, <i>eltAB</i>-II-c1-02, <i>eltAB</i>-II-c6-03, <i>eltAB</i>-II-c6-04 and <i>eltAB</i>-II-c7-02) were identified in livestock. Hybrid ETECs identified were ETEC/STEC present in 6.7% (4/60) of ETEC strains and ETEC with <i>cdt</i>ABC type I. An A2B5-like tripartite toxin, potentially resembling the typhoid toxin, was detected in 8.7% (4/46) of the <i>eltAB</i>-II-positive strains. It may have unique effects on enterocytes distinct from known toxins. These findings expand our understanding of ETEC pathogenicity and genetic diversity in animal reservoirs, while also highlighting potential zoonotic risks. They broaden the toxin repertoire, offer adhesin-based vaccine candidates for livestock and provide valuable insights for future vaccine development and public health strategies in the Lake Victoria Crescent ecosystem and beyond.
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spelling CGSpace1768682025-12-08T10:06:44Z Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya Njoroge, Samuel M. Kulohoma, B.W. Falzon, L.C. Kamanu, T.K. Momanyi, Kelvin Muinde, Patrick Murungi, Maurice K. Ogendo, A. Ogola, J. Wambua, Lillian Kang'ethe, Erastus Rushton, J. Woolhouse, M. Thomson, N.R. Kariuki, S. Mentzer, A. von Fèvre, Eric M. livestock Escherichia coli genomes Enterotoxigenic <i>Escherichia coli</i> (ETEC) is a significant cause of diarrhoea in livestock and humans. The epidemiology of ETEC in animals remains understudied, prompting an investigation into the virulence factors and associated adhesins of ETEC in livestock from Western Kenya. Also, there is limited evidence supporting the role of livestock as possible zoonotic reservoirs for ETEC. ETEC strains harbour colonization factors/adhesins and enterotoxins, with animal ETECs exhibiting various adhesins (F4, F5, F6, F17, F18 and F41). Enterotoxins include heat-labile (LT) and heat-stable (ST) toxins and are further divided into LT-I and LT-II and STa and STb, respectively. Additional toxin combinations occur, with ETEC and Shiga toxin-producing <i>E. coli</i> (STEC) hybrids garnering public health significance. Here, we analysed faecal and mesenteric lymph node samples from diverse livestock across three Western Kenyan counties (Busia, Bungoma and Kakamega), using whole-genome sequencing. <i>In silico</i> screening determined the presence of AB5 and A2B5-like toxin genes, including cytolethal distending toxin (<i>cdt</i>ABC) along with associated adhesins. To broaden the screening panel, adhesin genes identified were further characterized to identify both known and novel alleles, particularly focusing on human-ETEC colonization factors. Two <i>estA</i> alleles (<i>estA</i>-4-06, <i>estA</i>-6-02) and six <i>eltAB</i>-II toxin alleles (<i>eltAB</i>-II-a2-01, <i>eltAB</i>-II-a3-01, <i>eltAB</i>-II-c1-02, <i>eltAB</i>-II-c6-03, <i>eltAB</i>-II-c6-04 and <i>eltAB</i>-II-c7-02) were identified in livestock. Hybrid ETECs identified were ETEC/STEC present in 6.7% (4/60) of ETEC strains and ETEC with <i>cdt</i>ABC type I. An A2B5-like tripartite toxin, potentially resembling the typhoid toxin, was detected in 8.7% (4/46) of the <i>eltAB</i>-II-positive strains. It may have unique effects on enterocytes distinct from known toxins. These findings expand our understanding of ETEC pathogenicity and genetic diversity in animal reservoirs, while also highlighting potential zoonotic risks. They broaden the toxin repertoire, offer adhesin-based vaccine candidates for livestock and provide valuable insights for future vaccine development and public health strategies in the Lake Victoria Crescent ecosystem and beyond. 2025-09-25 2025-10-07T15:32:40Z 2025-10-07T15:32:40Z Journal Article https://hdl.handle.net/10568/176868 en Open Access Microbiology Society Njoroge, S.M., Kulohoma, B.W., Falzon, L.C., Kamanu, T.K., Momanyi, K., Muinde, P., Murungi, M.K., Ogendo, A., Ogola, J., Wambua, L., Kang'ethe, E., Rushton, J., Woolhouse, M., Thomson, N.R., Kariuki, S., Mentzer, A. von and Fèvre, E.M. 2025. Genomic profiling of enterotoxigenic <i>Escherichia coli</i> toxins and adhesins in livestock isolates from Kenya. Microbial Genomics 11(9): 001515.
spellingShingle livestock
Escherichia coli
genomes
Njoroge, Samuel M.
Kulohoma, B.W.
Falzon, L.C.
Kamanu, T.K.
Momanyi, Kelvin
Muinde, Patrick
Murungi, Maurice K.
Ogendo, A.
Ogola, J.
Wambua, Lillian
Kang'ethe, Erastus
Rushton, J.
Woolhouse, M.
Thomson, N.R.
Kariuki, S.
Mentzer, A. von
Fèvre, Eric M.
Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya
title Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya
title_full Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya
title_fullStr Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya
title_full_unstemmed Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya
title_short Genomic profiling of enterotoxigenic Escherichia coli toxins and adhesins in livestock isolates from Kenya
title_sort genomic profiling of enterotoxigenic escherichia coli toxins and adhesins in livestock isolates from kenya
topic livestock
Escherichia coli
genomes
url https://hdl.handle.net/10568/176868
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