Search

Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study, E. coli strains (n = 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%) E. coli strains to be virulent possessing either sta (n = 5), stx (stx1, n = 8; stx2, n = 2), or both (n = 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried both stx (either stx1 or stx2) and ETEC-specific enterotoxin gene sta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36: H5, O174: H-, O152: H8, O109: H51, and O8: H21, while the STEC-producing strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16 (n = 2), OR: H2 (n = 1), O110: H16 (n = 1), and O152: H8 (n = 1). The STEC-ETEC hybrid strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16, OR: H2, and O152: H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC-ETEC hybrid strains were highly heterogeneous. Multidrug-resistant E. coli STEC-ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.

Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study, E. coli strains (n = 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%) E. coli strains to be virulent possessing either sta (n = 5), stx (stx1, n = 8; stx2, n = 2), or both (n = 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried both stx (either stx1 or stx2) and ETEC-specific enterotoxin gene sta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36: H5, O174: H-, O152: H8, O109: H51, and O8: H21, while the STEC-producing strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16 (n = 2), OR: H2 (n = 1), O110: H16 (n = 1), and O152: H8 (n = 1). The STEC-ETEC hybrid strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16, OR: H2, and O152: H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC-ETEC hybrid strains were highly heterogeneous. Multidrug-resistant E. coli STEC-ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.

Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study, E. coli strains (n = 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%) E. coli strains to be virulent possessing either sta (n = 5), stx (stx1, n = 8; stx2, n = 2), or both (n = 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried both stx (either stx1 or stx2) and ETEC-specific enterotoxin gene sta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36: H5, O174: H-, O152: H8, O109: H51, and O8: H21, while the STEC-producing strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16 (n = 2), OR: H2 (n = 1), O110: H16 (n = 1), and O152: H8 (n = 1). The STEC-ETEC hybrid strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16, OR: H2, and O152: H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC-ETEC hybrid strains were highly heterogeneous. Multidrug-resistant E. coli STEC-ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.

Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study, E. coli strains (n = 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%) E. coli strains to be virulent possessing either sta (n = 5), stx (stx1, n = 8; stx2, n = 2), or both (n = 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried both stx (either stx1 or stx2) and ETEC-specific enterotoxin gene sta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36: H5, O174: H-, O152: H8, O109: H51, and O8: H21, while the STEC-producing strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16 (n = 2), OR: H2 (n = 1), O110: H16 (n = 1), and O152: H8 (n = 1). The STEC-ETEC hybrid strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16, OR: H2, and O152: H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC-ETEC hybrid strains were highly heterogeneous. Multidrug-resistant E. coli STEC-ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.

Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study, E. coli strains (n = 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%) E. coli strains to be virulent possessing either sta (n = 5), stx (stx1, n = 8; stx2, n = 2), or both (n = 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried both stx (either stx1 or stx2) and ETEC-specific enterotoxin gene sta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36: H5, O174: H-, O152: H8, O109: H51, and O8: H21, while the STEC-producing strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16 (n = 2), OR: H2 (n = 1), O110: H16 (n = 1), and O152: H8 (n = 1). The STEC-ETEC hybrid strains belonged to serotypes O76: H19 (n = 3), O43: H2 (n = 2), O87: H16, OR: H2, and O152: H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC-ETEC hybrid strains were highly heterogeneous. Multidrug-resistant E. coli STEC-ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.

Das hämolytische urämische Syndrom (eHUS) ist eine schwere Erkrankung des Menschen, die durch enterohemorrhagische Escherichia coli (EHEC) verursacht wird. Es wird angenommen, dass Komplement, eine Komponente der angeborenen Immunität, eine Rolle bei der Pathogenese von eHUS spielt. Der primäre EHEC-Virulenzfaktor, Shiga-Toxin 2a (Stx2a), aktiviert das Komplement über den alternativen Weg (AP) und bindet auch an Faktor H [1]. Diese Arbeit entschlüsselt einige der bisher unerforschten Rollen von Komplement im Krankheitsverlauf. Diskrepante Ergebnisse aus einem EHEC-Labor in Bologna, Italien, mit einem anderen Reinigungsprotokoll als im Innsbrucker Labor (in der gesamten Arbeit als Stx2a bezeichnet) ergaben eine bestimmte Sorte von Stx2a (als Stx2a (BO) bezeichnet). Dies führte zu einer gleichzeitigen Studie (Projekt I), in der Stx2a mit Stx2a (BO) hinsichtlich ihrer biologischen Eigenschaften verglichen wurde. Daher wurden die Experimente in den beiden anderen parallelen Projekten nur mit Stx2a durchgeführt und würden außerdem vergleichende Analysen mit Stx2a (BO) erfordern. In Projekt II wird die Interaktion von Stx2a mit den wichtigsten Komplementproteinen C3 und C5 untersucht. Angesichts der kürzlichen Bestätigung des intrazellulären Komplements konzentrierte sich Projekt II auch auf die Untersuchung der intrazellulären Synthese von AP-Komplementkomponenten bei Stimulation mit Stx2a in verschiedenen menschlichen Zelllinien. Projekt III untersucht die mögliche Rolle des Lektinpfads (LP) in der eHUS-Pathogenese, indem die Wechselwirkung von Stx2a mit den Serinproteasen (MASP-1 und -3) untersucht wird, die ausschließlich für die LP gelten. Daten aus dem ersten Projekt legen nahe, dass Stx2a und Stx2a (BO) sich in ihrer A-Untereinheit-Struktur unterscheiden, was zu zuvor kontroversen Ergebnissen führt und somit deren kritische Neubewertung durchsetzen kann. Das zweite Projekt berichtet über die intrazelluläre Expression von C3 und C5 im Darm sowie Nierenzellen bei Sti, Hemolytic Uremic Syndrome (eHUS) is a severe human disease caused by Enterohemorrhagic Escherichia coli (EHEC). Complement, a component of innate immunity, is believed to play a role in eHUS pathogenesis. The primary EHEC virulence factor, Shiga toxin 2a (Stx2a), activates complement via the alternative pathway (AP) and also binds to factor H [1]. This thesis decodes some of the previously unexplored roles of complement in disease progression. Discrepant results from an EHEC laboratory in Bologna, Italy, using a different purification protocol than in Innsbruck laboratory (designated as Stx2a throughout the thesis) yielded a particular variety of Stx2a (designated as Stx2a (BO)). This led to a concurrent study (Project I) that compared Stx2a to Stx2a (BO) in their biological properties. Therefore, the experiments in the other two parallel projects, have only been performed using Stx2a and would further require comparative analyses using Stx2a (BO) as well. Project II explores the interaction of Stx2a with pivotal complement proteins C3 and C5. Given the recent affirmation of intracellular complement, Project II also focused on investigating the intracellular synthesis of AP complement components upon stimulation with Stx2a, in various human cell lines. Project III traverses the possible role of lectin pathway (LP) in eHUS pathogenesis by investigating the interaction of Stx2a with the serine proteases (MASP-1 and -3), exclusive to the LP. Data from the first project suggest that Stx2a and Stx2a (BO) differ in their A-subunit structure leading to previously obtained controversial results and thus assert their critical re-evaluation. The second project reports the intracellular expression of C3 and C5 in gut as well as kidney cells upon stimulation with Stx2a and their binding to Stx2a, corroborating the involvement of complement in eHUS. The third project proclaims that Stx2a binds not only to MASP-1, but more profoundly to MASP-3, proposing a possible involvement of, by Sneha Chatterjee, Dissertation Medical University of Innsbruck 2018

Das hämolytische urämische Syndrom (eHUS) ist eine schwere Erkrankung des Menschen, die durch enterohemorrhagische Escherichia coli (EHEC) verursacht wird. Es wird angenommen, dass Komplement, eine Komponente der angeborenen Immunität, eine Rolle bei der Pathogenese von eHUS spielt. Der primäre EHEC-Virulenzfaktor, Shiga-Toxin 2a (Stx2a), aktiviert das Komplement über den alternativen Weg (AP) und bindet auch an Faktor H [1]. Diese Arbeit entschlüsselt einige der bisher unerforschten Rollen von Komplement im Krankheitsverlauf. Diskrepante Ergebnisse aus einem EHEC-Labor in Bologna, Italien, mit einem anderen Reinigungsprotokoll als im Innsbrucker Labor (in der gesamten Arbeit als Stx2a bezeichnet) ergaben eine bestimmte Sorte von Stx2a (als Stx2a (BO) bezeichnet). Dies führte zu einer gleichzeitigen Studie (Projekt I), in der Stx2a mit Stx2a (BO) hinsichtlich ihrer biologischen Eigenschaften verglichen wurde. Daher wurden die Experimente in den beiden anderen parallelen Projekten nur mit Stx2a durchgeführt und würden außerdem vergleichende Analysen mit Stx2a (BO) erfordern. In Projekt II wird die Interaktion von Stx2a mit den wichtigsten Komplementproteinen C3 und C5 untersucht. Angesichts der kürzlichen Bestätigung des intrazellulären Komplements konzentrierte sich Projekt II auch auf die Untersuchung der intrazellulären Synthese von AP-Komplementkomponenten bei Stimulation mit Stx2a in verschiedenen menschlichen Zelllinien. Projekt III untersucht die mögliche Rolle des Lektinpfads (LP) in der eHUS-Pathogenese, indem die Wechselwirkung von Stx2a mit den Serinproteasen (MASP-1 und -3) untersucht wird, die ausschließlich für die LP gelten. Daten aus dem ersten Projekt legen nahe, dass Stx2a und Stx2a (BO) sich in ihrer A-Untereinheit-Struktur unterscheiden, was zu zuvor kontroversen Ergebnissen führt und somit deren kritische Neubewertung durchsetzen kann. Das zweite Projekt berichtet über die intrazelluläre Expression von C3 und C5 im Darm sowie Nierenzellen bei Sti, Hemolytic Uremic Syndrome (eHUS) is a severe human disease caused by Enterohemorrhagic Escherichia coli (EHEC). Complement, a component of innate immunity, is believed to play a role in eHUS pathogenesis. The primary EHEC virulence factor, Shiga toxin 2a (Stx2a), activates complement via the alternative pathway (AP) and also binds to factor H [1]. This thesis decodes some of the previously unexplored roles of complement in disease progression. Discrepant results from an EHEC laboratory in Bologna, Italy, using a different purification protocol than in Innsbruck laboratory (designated as Stx2a throughout the thesis) yielded a particular variety of Stx2a (designated as Stx2a (BO)). This led to a concurrent study (Project I) that compared Stx2a to Stx2a (BO) in their biological properties. Therefore, the experiments in the other two parallel projects, have only been performed using Stx2a and would further require comparative analyses using Stx2a (BO) as well. Project II explores the interaction of Stx2a with pivotal complement proteins C3 and C5. Given the recent affirmation of intracellular complement, Project II also focused on investigating the intracellular synthesis of AP complement components upon stimulation with Stx2a, in various human cell lines. Project III traverses the possible role of lectin pathway (LP) in eHUS pathogenesis by investigating the interaction of Stx2a with the serine proteases (MASP-1 and -3), exclusive to the LP. Data from the first project suggest that Stx2a and Stx2a (BO) differ in their A-subunit structure leading to previously obtained controversial results and thus assert their critical re-evaluation. The second project reports the intracellular expression of C3 and C5 in gut as well as kidney cells upon stimulation with Stx2a and their binding to Stx2a, corroborating the involvement of complement in eHUS. The third project proclaims that Stx2a binds not only to MASP-1, but more profoundly to MASP-3, proposing a possible involvement of, by Sneha Chatterjee, Dissertation Medical University of Innsbruck 2018