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Romão FT, Martins FH, Hernandes RT, Ooka T, Santos FF, Yamamoto D, Bonfim-Melo A, Jones N, Hayashi T, Elias WP, Sperandio V, Gomes TAT. Genomic Properties and Temporal Analysis of the Interaction of an Invasive Escherichia albertii With Epithelial Cells. Front Cell Infect Microbiol 2020; 10:571088. [PMID: 33392102 PMCID: PMC7772469 DOI: 10.3389/fcimb.2020.571088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 11/03/2020] [Indexed: 12/17/2022] Open
Abstract
Diarrhea is one of the main causes of infant mortality worldwide, mainly in the developing world. Among the various etiologic agents, Escherichia albertii is emerging as an important human enteropathogen. E. albertii promote attaching and effacing (AE) lesions due to the presence of the locus of enterocyte effacement (LEE) that encodes a type three secretion system (T3SS), the afimbrial adhesin intimin and its translocated receptor, Tir, and several effector proteins. We previously showed that E. albertii strain 1551-2 invades several epithelial cell lineages by a process that is dependent on the intimin-Tir interaction. To understand the contribution of T3SS-dependent effectors present in E. albertii 1551-2 during the invasion process, we performed a genetic analysis of the LEE and non-LEE genes and evaluated the expression of the LEE operons in various stages of bacterial interaction with differentiated intestinal Caco-2 cells. The kinetics of the ability of the 1551-2 strain to colonize and form AE lesions was also investigated in epithelial HeLa cells. We showed that the LEE expression was constant during the early stages of infection but increased at least 4-fold during bacterial persistence in the intracellular compartment. An in silico analysis indicated the presence of a new tccP/espFU subtype, named tccP3. We found that the encoded protein colocalizes with Tir and polymerized F-actin during the infection process in vitro. Moreover, assays performed with Nck null cells demonstrated that the 1551-2 strain can trigger F-actin polymerization in an Nck-independent pathway, despite the fact that TccP3 is not required for this phenotype. Our study highlights the importance of the T3SS during the invasion process and for the maintenance of E. albertii 1551-2 inside the cells. In addition, this work may help to elucidate the versatility of the T3SS for AE pathogens, which are usually considered extracellular and rarely reach the intracellular environment.
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Affiliation(s)
- Fabiano T Romão
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil.,Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Fernando H Martins
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Rodrigo T Hernandes
- Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, Brazil
| | - Tadasuke Ooka
- Department of Microbiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Fernanda F Santos
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil
| | - Denise Yamamoto
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil.,Universidade Santo Amaro, São Paulo, Brazil
| | - Alexis Bonfim-Melo
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil
| | - Nina Jones
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Vanessa Sperandio
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Tânia A T Gomes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-UNIFESP), São Paulo, Brazil
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Gomes TAT, Ooka T, Hernandes RT, Yamamoto D, Hayashi T. Escherichia albertii Pathogenesis. EcoSal Plus 2020; 9:10.1128/ecosalplus.ESP-0015-2019. [PMID: 32588811 PMCID: PMC11168576 DOI: 10.1128/ecosalplus.esp-0015-2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Indexed: 12/17/2022]
Abstract
Escherichia albertii is an emerging enteropathogen of humans and many avian species. This bacterium is a close relative of Escherichia coli and has been frequently misidentified as enteropathogenic or enterohemorrhagic E. coli due to their similarity in phenotypic and genetic features, such as various biochemical properties and the possession of a type III secretion system encoded by the locus of enterocyte effacement. This pathogen causes outbreaks of gastroenteritis, and some strains produce Shiga toxin. Although many genetic and phenotypic studies have been published and the genome sequences of more than 200 E. albertii strains are now available, the clinical significance of this species is not yet fully understood. The apparent zoonotic nature of the disease requires a deeper understanding of the transmission routes and mechanisms of E. albertii to develop effective measures to control its transmission and infection. Here, we review the current knowledge of the phylogenic relationship of E. albertii with other Escherichia species and the biochemical and genetic properties of E. albertii, with particular emphasis on the repertoire of virulence factors and the mechanisms of pathogenicity, and we hope this provides a basis for future studies of this important emerging enteropathogen.
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Affiliation(s)
- Tânia A T Gomes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Tadasuke Ooka
- Department of Microbiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Rodrigo T Hernandes
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, Campus de Botucatu, São Paulo, Brazil
| | - Denise Yamamoto
- Universidade Santo Amaro, São Paulo, Brazil
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
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Abstract
Bacterial pathogens have evolved to regulate virulence gene expression at critical points in the colonization and infection processes to successfully cause disease. The Shigella species infect the epithelial cells lining the colon to result in millions of cases of diarrhea and a significant global health burden. As antibiotic resistance rates increase, understanding the mechanisms of infection is vital to ensure successful vaccine development. Despite significant gains in our understanding of Shigella infection, it remains unknown how the bacteria initiate contact with the colonic epithelium. Most pathogens harbor multiple adherence factors to facilitate this process, but Shigella was thought to have lost the ability to produce these factors. Interestingly, we have identified conditions that mimic some features of gastrointestinal transit and that enable Shigella to express adherence structural genes. This work highlights aspects of genetic regulation for Shigella adherence factors and may have a significant impact on future vaccine development. The Shigella species are Gram-negative, facultative intracellular pathogens that invade the colonic epithelium and cause significant diarrheal disease. Despite extensive research on the pathogen, a comprehensive understanding of how Shigella initiates contact with epithelial cells remains unknown. Shigella maintains many of the same Escherichia coli adherence gene operons; however, at least one critical gene component in each operon is currently annotated as a pseudogene in reference genomes. These annotations, coupled with a lack of structures upon microscopic analysis following growth in laboratory media, have led the field to hypothesize that Shigella is unable to produce fimbriae or other traditional adherence factors. Nevertheless, our previous analyses have demonstrated that a combination of bile salts and glucose induces both biofilm formation and adherence to colonic epithelial cells. The goal of this study was to perform transcriptomic and genetic analyses to demonstrate that adherence gene operons in Shigella flexneri strain 2457T are functional, despite the gene annotations. Our results demonstrate that at least three structural genes facilitate S. flexneri 2457T adherence for epithelial cell contact and biofilm formation. Furthermore, our results demonstrate that host factors, namely, glucose and bile salts at their physiological concentrations in the small intestine, offer key environmental stimuli required for adherence factor expression in S. flexneri. This research may have a significant impact on Shigella vaccine development and further highlights the importance of utilizing in vivo-like conditions to study bacterial pathogenesis. IMPORTANCE Bacterial pathogens have evolved to regulate virulence gene expression at critical points in the colonization and infection processes to successfully cause disease. The Shigella species infect the epithelial cells lining the colon to result in millions of cases of diarrhea and a significant global health burden. As antibiotic resistance rates increase, understanding the mechanisms of infection is vital to ensure successful vaccine development. Despite significant gains in our understanding of Shigella infection, it remains unknown how the bacteria initiate contact with the colonic epithelium. Most pathogens harbor multiple adherence factors to facilitate this process, but Shigella was thought to have lost the ability to produce these factors. Interestingly, we have identified conditions that mimic some features of gastrointestinal transit and that enable Shigella to express adherence structural genes. This work highlights aspects of genetic regulation for Shigella adherence factors and may have a significant impact on future vaccine development.
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Complete Genome Sequence of Escherichia albertii Strain 1551-2, a Potential Extracellular and Intracellular Pathogen. GENOME ANNOUNCEMENTS 2018; 6:6/9/e00075-18. [PMID: 29496827 PMCID: PMC5834326 DOI: 10.1128/genomea.00075-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Escherichia albertii has recently been recognized as an emerging human and bird enteric pathogen. Here, we report the complete chromosome sequence of a clinical isolate of E. albertii strain 1551-2, which may provide information about the pathogenic potential of this new species and the mechanisms of evolution of Escherichia species.
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Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection. Clin Microbiol Rev 2017; 29:819-36. [PMID: 27464994 DOI: 10.1128/cmr.00031-16] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to this in vivo signal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens.
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Escherichia albertii, a novel human enteropathogen, colonizes rat enterocytes and translocates to extra-intestinal sites. PLoS One 2017; 12:e0171385. [PMID: 28178312 PMCID: PMC5298312 DOI: 10.1371/journal.pone.0171385] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/18/2017] [Indexed: 01/01/2023] Open
Abstract
Diarrhea is the second leading cause of death of children up to five years old in the developing countries. Among the etiological diarrheal agents are atypical enteropathogenic Escherichia coli (aEPEC), one of the diarrheagenic E. coli pathotypes that affects children and adults, even in developed countries. Currently, genotypic and biochemical approaches have helped to demonstrate that some strains classified as aEPEC are actually E. albertii, a recently recognized human enteropathogen. Studies on particular strains are necessary to explore their virulence potential in order to further understand the underlying mechanisms of E. albertii infections. Here we demonstrated for the first time that infection of fragments of rat intestinal mucosa is a useful tool to study the initial steps of E. albertii colonization. We also observed that an E. albertii strain can translocate from the intestinal lumen to Mesenteric Lymph Nodes and liver in a rat model. Based on our finding of bacterial translocation, we investigated how E. albertii might cross the intestinal epithelium by performing infections of M-like cells in vitro to identify the potential in vivo translocation route. Altogether, our approaches allowed us to draft a general E. albertii infection route from the colonization till the bacterial spreading in vivo.
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