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Liu Q, Yang X, Sun H, Wang H, Sui X, Zhang P, Bai X, Xiong Y. Genetic Diversity and Expression of Intimin in Escherichia albertii Isolated from Humans, Animals, and Food. Microorganisms 2023; 11:2843. [PMID: 38137987 PMCID: PMC10745426 DOI: 10.3390/microorganisms11122843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/16/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
Escherichia albertii (E. albertii) is an emerging diarrheagenic pathogen associated with sporadic infections and human gastroenteric outbreaks. The eae gene, which encodes intimin in the locus of enterocyte effacement (LEE) operon, contributes to the establishment of the attaching and effacing (A/E) lesion. Increasing collection of E. albertii strains from various sources has resulted in a rapid increase in the number of eae subtypes. This study systematically investigated the prevalence and genetic diversity of eae among E. albertii strains isolated from humans, animals, and food. The eae gene was present in 452/459 (98.5%) strains and 23 subtypes were identified including two novel subtypes, named eae-α11 and η3. The eae-σ subtype was the most predominant among humans, animals, and food-derived strains, while eae-γ3, τ, and α11 were unique in human-derived strains. Additionally, the LEE island was also analyzed at genomic, transcriptional, and functional levels through genomic analysis, quantitative reverse transcription PCR, and HEp-2 cell adherence assays, respectively. The eae transcript levels were variable and associated with eae subtypes. Three different adherence patterns, including localized adherence-like (LAL), diffuse adherence (DA), and detachment (DE), were observed among E. albertii strains. This study demonstrated a high diversity of functional intimin in E. albertii strains isolated from humans, animals, and food. Further in vivo and in vitro studies are warranted to better elucidate the role of intimin or LEE in different genetic backgrounds.
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Affiliation(s)
- Qian Liu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
| | - Xi Yang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
| | - Hui Sun
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
| | - Hua Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
| | - Xinxia Sui
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
| | - Peihua Zhang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
| | - Xiangning Bai
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
- Division of Laboratory Medicine, Oslo University Hospital, 0372 Oslo, Norway
| | - Yanwen Xiong
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; (Q.L.); (X.Y.); (H.S.); (H.W.); (X.S.); (P.Z.); (X.B.)
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Cryoelectron-microscopy structure of the enteropathogenic Escherichia coli type III secretion system EspA filament. Proc Natl Acad Sci U S A 2021; 118:2022826118. [PMID: 33397726 PMCID: PMC7812819 DOI: 10.1073/pnas.2022826118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic Escherichia coli (EHEC) utilize a macromolecular type III secretion system (T3SS) to inject effector proteins into eukaryotic cells. This apparatus spans the inner and outer bacterial membranes and includes a helical needle protruding into the extracellular space. Thus far observed only in EPEC and EHEC and not found in other pathogenic Gram-negative bacteria that have a T3SS is an additional helical filament made by the EspA protein that forms a long extension to the needle, mediating both attachment to eukaryotic cells and transport of effector proteins through the intestinal mucus layer. Here, we present the structure of the EspA filament from EPEC at 3.4 Å resolution. The structure reveals that the EspA filament is a right-handed 1-start helical assembly with a conserved lumen architecture with respect to the needle to ensure the seamless transport of unfolded cargos en route to the target cell. This functional conservation is despite the fact that there is little apparent overall conservation at the level of sequence or structure with the needle. We also unveil the molecular details of the immunodominant EspA epitope that can now be exploited for the rational design of epitope display systems.
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