Analysis of the mechanism of HUS pathogenesis by Stx2f-producing Escherichia sp.

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K15159
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Ishijima Nozomi 国立感染症研究所, 細菌第一部, 研究員 (60565604)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: HUS / Stx / 腸管出血性大腸菌 / 志賀毒素 / E. alberti

Outline of Final Research Achievements

Although most E. albertii infections are mild, E. albertii isolated from a HUS case was inferred to be the causative organism and was confirmed to harbor the Shiga toxin stx2f gene.Since Stx2f is a subtype whose details are still unknown, we evaluated the Stx2f toxicity of this strain. As a result, this strain produced little Stx2f, but we obtained E. coli K-12 strain harboring the stx2f phage derived from this strain, which showed clear Stx2f production. Although the expression of this Stx2f phage is suppressed in the background of E. albertii, it is possible that its toxicity is enhanced when it is acquired by phage-susceptible bacteria in the environment or in the host.

Free Research Field

病原細菌

Academic Significance and Societal Importance of the Research Achievements

E. albertiiは新興病原菌であり、これまでの本菌感染症は軽症例がほとんどあったことから、病原性発揮メカニズム、ヒト感染における重症化リスク等未だ不明点が多い。本研究で分離したE. albertiiは、HUS原因菌として世界で初めてのケースであり、本菌をモデル株として行った解析結果は、学術的意義を有すると考えらえる。Stx2fファージ保有菌自体の毒素産生性が検出されないが、ヒト感染においては重大な病原性を発揮する可能性を示したことは、公衆衛生上の重要な知見であると考えている。