1
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Burns L, Le Mauff F, Gruenheid S. Direct evidence of host-mediated glycosylation of NleA and its dependence on interaction with the COPII complex. Gut Microbes 2024; 16:2305477. [PMID: 38298145 PMCID: PMC10841024 DOI: 10.1080/19490976.2024.2305477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2024] Open
Abstract
Non-LEE-encoded Effector A (NleA) is a type III secreted effector protein of enterohaemorrhagic and enteropathogenic Escherichia coli as well as the related mouse pathogen Citrobacter rodentium. NleA translocation into host cells is essential for virulence. We previously published several lines of evidence indicating that NleA is modified by host-mediated mucin-type O-linked glycosylation, the first example of a bacterial effector protein modified in this way. In this study, we use lectins to provide direct evidence for the modification of NleA by O-linked glycosylation and determine that the interaction of NleA with the COPII complex is necessary for this modification to occur.
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Affiliation(s)
- Lindsay Burns
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - François Le Mauff
- Infectious Disease and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Glyco-NET Integrated Services, Microbial Glycomic Node, Montreal, QC, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, QC, Canada
| | - Samantha Gruenheid
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
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2
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Yun YS, Park DY, Oh IH, Shin WR, Ahn G, Ahn JY, Kim YH. Pathogenic Factors and Recent Study on the Rapid Detection of Shiga Toxin-Producing Escherichia coli (STEC). Mol Biotechnol 2023:10.1007/s12033-023-00985-8. [PMID: 38153662 DOI: 10.1007/s12033-023-00985-8] [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: 07/30/2023] [Accepted: 11/05/2023] [Indexed: 12/29/2023]
Abstract
This comprehensive review delves into the pathogenicity and detection of Shiga Toxin-Producing Escherichia coli (STEC), shedding light on its various genetic and clinical manifestations. STEC originating from E. coli acquires pathogenicity through mobility and genetic elements. The pathogenicity of STEC is explored in terms of clinical progression, complications, and key toxins such as Shiga toxin (Stx). Stx1 and Stx2 are two distinct Stx types exhibiting different toxicities, with Stx2 often associated with severe diseases. This review also delves into Subtilase cytotoxin, an additional cytotoxin produced by some STEC strains. Pathogenic mechanisms of STEC, such as attaching and effacing intestinal lesions, are discussed, with a focus on roles of genetic factors. Plasmids in STEC can confer unique pathogenicity. Hybridization with other pathogenic E. coli can create more lethal pathogens. This review covers a range of detection methods, ranging from DNA amplification to antigen detection techniques, emphasizing the need for innovative approaches to improve the sensitivity and speed of STEC diagnosis. In conclusion, understanding diverse aspects of STEC pathogenicity and exploring enhanced diagnostic methods are critical to addressing this foodborne pathogen effectively. Pathology of Shiga toxin toxicity. STEC-derived Shiga toxin consists of one A subunit and five B subunits. Pathological symptoms of the disease can progress to HUS within two weeks after the onset of diarrhea. Shiga toxin intoxication is also associated with many complications, such as neurological and cardiac complications. This figure was reconstructed based on data from Bruyand et al.
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Affiliation(s)
- Young-Sun Yun
- Department of Microbiology, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, 28644, Republic of Korea
| | - Dae-Young Park
- Department of Microbiology, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, 28644, Republic of Korea
| | - In-Hwan Oh
- Department of Microbiology, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, 28644, Republic of Korea
| | - Woo-Ri Shin
- Department of Bioengineering, University of Pennsylvania, 210 S 33rd St., Philadelphia, PA, 19104, USA
| | - Gna Ahn
- Center for Ecology and Environmental Toxicology, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Ji-Young Ahn
- Department of Microbiology, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, 28644, Republic of Korea.
| | - Yang-Hoon Kim
- Department of Microbiology, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, 28644, Republic of Korea.
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3
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Burns L, Giannakopoulou N, Zhu L, Xu YZ, Khan RH, Bekal S, Schurr E, Schmeing TM, Gruenheid S. The bacterial virulence factor NleA undergoes host-mediated O-linked glycosylation. Mol Microbiol 2023; 119:161-173. [PMID: 36196760 DOI: 10.1111/mmi.14989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 09/01/2022] [Accepted: 09/29/2022] [Indexed: 11/28/2022]
Abstract
Enterohaemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) are gastrointestinal pathogens responsible for severe diarrheal illness. EHEC and EPEC form "attaching and effacing" lesions during colonization and, upon adherence, inject proteins directly into host intestinal cells via the type III secretion system (T3SS). Injected bacterial proteins have a variety of functions but generally alter host cell biology to favor survival and/or replication of the pathogen. Non-LEE-encoded effector A (NleA) is a T3SS-injected effector of EHEC, EPEC, and the related mouse pathogen Citrobacter rodentium. Studies in mouse models indicate that NleA has an important role in bacterial virulence. However, the mechanism by which NleA contributes to disease remains unknown. We have determined that the following translocation into host cells, a serine and threonine-rich region of NleA is modified by host-mediated mucin-type O-linked glycosylation. Surprisingly, this region was not present in several clinical EHEC isolates. When expressed in C. rodentium, a non-modifiable variant of NleA was indistinguishable from wildtype NleA in an acute mortality model but conferred a modest increase in persistence over the course of infection in mixed infections in C57BL/6J mice. This is the first known example of a bacterial effector being modified by host-mediated O-linked glycosylation. Our data also suggests that this modification may confer a selective disadvantage to the bacteria during in vivo infection.
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Affiliation(s)
- Lindsay Burns
- McGill Research Centre on Complex Traits and Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Natalia Giannakopoulou
- McGill Research Centre on Complex Traits and Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Lei Zhu
- McGill Research Centre on Complex Traits and Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Yong Zhong Xu
- Program in Infectious Diseases and Global Health, The Research Institute of the McGill University Health Centre and McGill International TB Centre, Department of Medicine, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Rufaida H Khan
- Laboratoire de Santé Publique du Québec, Institut National de Santé Publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.,Department of Food Science and Agricultural Chemistry, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada
| | - Sadjia Bekal
- Laboratoire de Santé Publique du Québec, Institut National de Santé Publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Erwin Schurr
- Program in Infectious Diseases and Global Health, The Research Institute of the McGill University Health Centre and McGill International TB Centre, Department of Medicine, Faculty of Medicine, McGill University, Montréal, Québec, Canada.,Department of Biochemistry, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - T Martin Schmeing
- Department of Biochemistry, Faculty of Medicine, McGill University, Montréal, Québec, Canada.,Centre de Recherche en Biologie Structurale, McGill University, Montréal, Québec, Canada
| | - Samantha Gruenheid
- McGill Research Centre on Complex Traits and Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
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4
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Kaur P, Dudeja PK. Pathophysiology of Enteropathogenic Escherichia coli-induced Diarrhea. NEWBORN (CLARKSVILLE, MD.) 2023; 2:102-113. [PMID: 37388762 PMCID: PMC10308259 DOI: 10.5005/jp-journals-11002-0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
Enteropathogenic Escherichia coli (EPEC) are important diarrheal pathogens of infants and young children. Since the availability of molecular diagnosis methods, we now have new insights into the incidence and prevalence of these infections. Recent epidemiological studies indicate that atypical EPEC (aEPEC) are seen more frequently than typical EPEC (tEPEC) worldwide, including in both endemic diarrhea and diarrhea outbreaks. Therefore, it is important to further characterize the pathogenicity of these emerging strains. The virulence mechanisms and pathophysiology of the attaching and effacing lesion (A/E) and the type-three-secretion-system (T3SS) are complex but well-studied. A/E strains use their pool of locus of enterocyte effacement (LEE)-encoded and non-LEE-encoded effector proteins to subvert and modulate cellular and barrier properties of the host. However, the exact mechanisms of diarrhea in EPEC infection are not completely understood. From the clinical perspective, there is a need for fast, easy, and inexpensive diagnostic methods to define optimal treatment and prevention for children in endemic areas. In this article, we present a review of the classification of EPEC, epidemiology, pathogenesis of the disease caused by these bacteria, determinants of virulence, alterations in signaling, determinants of colonization vs. those of disease, and the limited information we have on the pathophysiology of EPEC-induced diarrhea. This article combines peer-reviewed evidence from our own studies and the results of an extensive literature search in the databases PubMed, EMBASE, and Scopus.
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Affiliation(s)
- Prabhdeep Kaur
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Illinois, United States of America
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, United States of America
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5
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Mining of Thousands of Prokaryotic Genomes Reveals High Abundance of Prophages with a Strictly Narrow Host Range. mSystems 2022; 7:e0032622. [PMID: 35880895 PMCID: PMC9426530 DOI: 10.1128/msystems.00326-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Phages and prophages are one of the principal modulators of microbial populations. However, much of their diversity is still poorly understood. Here, we extracted 33,624 prophages from 13,713 complete prokaryotic genomes to explore the prophage diversity and their relationships with their host. Our results reveal that prophages were present in 75% of the genomes studied. In addition, Enterobacterales were significantly enriched in prophages. We also found that pathogens are a significant reservoir of prophages. Finally, we determined that the prophage relatedness and the range of genomic hosts were delimited by the evolutionary relationships of their hosts. On a broader level, we got insights into the prophage population, identified in thousands of publicly available prokaryotic genomes, by comparing the prophage distribution and relatedness between them and their hosts. IMPORTANCE Phages and prophages play an essential role in controlling their host populations either by modulating the host abundance or providing them with genes that benefit the host. The constant growth in next-generation sequencing technology has caused the development of powerful computational tools to identify phages and prophages with high precision. Making it possible to explore the prophage populations integrated into host genomes on a large scale. However, it is still a new and under-explored area, and efforts are still required to identify prophage populations to understand their dynamics with their hosts.
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6
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Tantoso E, Eisenhaber B, Kirsch M, Shitov V, Zhao Z, Eisenhaber F. To kill or to be killed: pangenome analysis of Escherichia coli strains reveals a tailocin specific for pandemic ST131. BMC Biol 2022; 20:146. [PMID: 35710371 PMCID: PMC9205054 DOI: 10.1186/s12915-022-01347-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 06/08/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Escherichia coli (E. coli) has been one of the most studied model organisms in the history of life sciences. Initially thought just to be commensal bacteria, E. coli has shown wide phenotypic diversity including pathogenic isolates with great relevance to public health. Though pangenome analysis has been attempted several times, there is no systematic functional characterization of the E. coli subgroups according to the gene profile. RESULTS Systematically scanning for optimal parametrization, we have built the E. coli pangenome from 1324 complete genomes. The pangenome size is estimated to be ~25,000 gene families (GFs). Whereas the core genome diminishes as more genomes are added, the softcore genome (≥95% of strains) is stable with ~3000 GFs regardless of the total number of genomes. Apparently, the softcore genome (with a 92% or 95% generation threshold) can define the genome of a bacterial species listing the critically relevant, evolutionarily most conserved or important classes of GFs. Unsupervised clustering of common E. coli sequence types using the presence/absence GF matrix reveals distinct characteristics of E. coli phylogroups B1, B2, and E. We highlight the bi-lineage nature of B1, the variation of the secretion and of the iron acquisition systems in ST11 (E), and the incorporation of a highly conserved prophage into the genome of ST131 (B2). The tail structure of the prophage is evolutionarily related to R2-pyocin (a tailocin) from Pseudomonas aeruginosa PAO1. We hypothesize that this molecular machinery is highly likely to play an important role in protecting its own colonies; thus, contributing towards the rapid rise of pandemic E. coli ST131. CONCLUSIONS This study has explored the optimized pangenome development in E. coli. We provide complete GF lists and the pangenome matrix as supplementary data for further studies. We identified biological characteristics of different E. coli subtypes, specifically for phylogroups B1, B2, and E. We found an operon-like genome region coding for a tailocin specific for ST131 strains. The latter is a potential killer weapon providing pandemic E. coli ST131 with an advantage in inter-bacterial competition and, suggestively, explains their dominance as human pathogen among E. coli strains.
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Affiliation(s)
- Erwin Tantoso
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (A*STAR), 60 Biopolis Street, Singapore, 138672, Republic of Singapore.,Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street #07-01, Matrix Building, Singapore, 138671, Republic of Singapore
| | - Birgit Eisenhaber
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (A*STAR), 60 Biopolis Street, Singapore, 138672, Republic of Singapore.,Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street #07-01, Matrix Building, Singapore, 138671, Republic of Singapore
| | - Miles Kirsch
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street #07-01, Matrix Building, Singapore, 138671, Republic of Singapore.,Present address: Northeastern University, Boston, USA
| | - Vladimir Shitov
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street #07-01, Matrix Building, Singapore, 138671, Republic of Singapore
| | - Zhiya Zhao
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street #07-01, Matrix Building, Singapore, 138671, Republic of Singapore.,Present address: The University of Cambridge, Cambridge, UK
| | - Frank Eisenhaber
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (A*STAR), 60 Biopolis Street, Singapore, 138672, Republic of Singapore. .,Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street #07-01, Matrix Building, Singapore, 138671, Republic of Singapore. .,School of Biological Sciences (SBS), Nanyang Technological University (NTU), 60 Nanyang Drive, 637551, Singapore, Republic of Singapore.
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7
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Iannino F, Uriza PJ, Duarte CM, Pepe MV, Roset MS, Briones G. Development of a Salmonella-based oral vaccine to control intestinal colonization of Shiga-toxin-producing Escherichia coli (STEC) in animals. Vaccine 2022; 40:1065-1073. [DOI: 10.1016/j.vaccine.2022.01.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/12/2022] [Accepted: 01/17/2022] [Indexed: 11/17/2022]
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8
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Lee JB, Kim SK, Yoon JW. Pathophysiology of enteropathogenic Escherichia coli during a host infection. J Vet Sci 2022; 23:e28. [PMID: 35187883 PMCID: PMC8977535 DOI: 10.4142/jvs.21160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 11/20/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.
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Affiliation(s)
- Jun Bong Lee
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Se Kye Kim
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Jang Won Yoon
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
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9
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Park DS, Park JH. Characteristics of Bacteriophage Isolates and Expression of Shiga Toxin Genes Transferred to Non Shiga Toxin-Producing E. coli by Transduction. J Microbiol Biotechnol 2021; 31:710-716. [PMID: 33782222 PMCID: PMC9705938 DOI: 10.4014/jmb.2102.02040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 12/15/2022]
Abstract
A risk analysis of Shiga toxin (Stx)-encoding bacteriophage was carried out by confirming the transduction phage to non-Stx-producing Escherichia coli (STEC) and subsequent expression of the Shiga toxin genes. The virulence factor stx1 was identified in five phages, and both stx1 and stx2 were found in four phages from a total of 19 phage isolates with seven non-O157 STEC strains. The four phages, designated as φNOEC41, φNOEC46, φNOEC47, and φNOEC49, belonged morphologically to the Myoviridae family. The stabilities of these phages to temperature, pH, ethanol, and NaClO were high with some variabilities among the phages. The infection of five non-STEC strains by nine Stx-encoding phages occurred at a rate of approximately 40%. Non-STEC strains were transduced by Stx-encoding phage to become lysogenic strains, and seven convertant strains had stx1 and/or stx2 genes. Only the stx1 gene was transferred to the receptor strains without any deletion. Gene expression of a convertant having both stx1 and stx2 genes was confirmed to be up to 32 times higher for Stx1 in 6% NaCl osmotic media and twice for Stx2 in 4% NaCl media, compared with expression in low-salt environments. Therefore, a new risk might arise from the transfer of pathogenic genes from Stx-encoding phages to otherwise harmless hosts. Without adequate sterilization of food exposed to various environments, there is a possibility that the toxicity of the phages might increase.
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Affiliation(s)
- Da-Som Park
- Department of Food Science and Biotechnology, College of BioNano Technology, Gachon University, Seongnam 13120, Republic of Korea
| | - Jong-Hyun Park
- Department of Food Science and Biotechnology, College of BioNano Technology, Gachon University, Seongnam 13120, Republic of Korea,Corresponding author Phone: +82-31-750-5523 Fax: +82-31-750-5283 E-mail:
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10
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Desvaux M, Dalmasso G, Beyrouthy R, Barnich N, Delmas J, Bonnet R. Pathogenicity Factors of Genomic Islands in Intestinal and Extraintestinal Escherichia coli. Front Microbiol 2020; 11:2065. [PMID: 33101219 PMCID: PMC7545054 DOI: 10.3389/fmicb.2020.02065] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022] Open
Abstract
Escherichia coli is a versatile bacterial species that includes both harmless commensal strains and pathogenic strains found in the gastrointestinal tract in humans and warm-blooded animals. The growing amount of DNA sequence information generated in the era of "genomics" has helped to increase our understanding of the factors and mechanisms involved in the diversification of this bacterial species. The pathogenic side of E. coli that is afforded through horizontal transfers of genes encoding virulence factors enables this bacterium to become a highly diverse and adapted pathogen that is responsible for intestinal or extraintestinal diseases in humans and animals. Many of the accessory genes acquired by horizontal transfers form syntenic blocks and are recognized as genomic islands (GIs). These genomic regions contribute to the rapid evolution, diversification and adaptation of E. coli variants because they are frequently subject to rearrangements, excision and transfer, as well as to further acquisition of additional DNA. Here, we review a subgroup of GIs from E. coli termed pathogenicity islands (PAIs), a concept defined in the late 1980s by Jörg Hacker and colleagues in Werner Goebel's group at the University of Würzburg, Würzburg, Germany. As with other GIs, the PAIs comprise large genomic regions that differ from the rest of the genome by their G + C content, by their typical insertion within transfer RNA genes, and by their harboring of direct repeats (at their ends), integrase determinants, or other mobility loci. The hallmark of PAIs is their contribution to the emergence of virulent bacteria and to the development of intestinal and extraintestinal diseases. This review summarizes the current knowledge on the structure and functional features of PAIs, on PAI-encoded E. coli pathogenicity factors and on the role of PAIs in host-pathogen interactions.
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Affiliation(s)
- Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, Clermont-Ferrand, France
| | - Guillaume Dalmasso
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Racha Beyrouthy
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Nicolas Barnich
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Julien Delmas
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Richard Bonnet
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
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11
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Pintara A, Jennison A, Rathnayake IU, Mellor G, Huygens F. Core and Accessory Genome Comparison of Australian and International Strains of O157 Shiga Toxin-Producing Escherichia coli. Front Microbiol 2020; 11:566415. [PMID: 33013798 PMCID: PMC7498637 DOI: 10.3389/fmicb.2020.566415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/17/2020] [Indexed: 12/20/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen, and serotype O157:H7 is typically associated with severe disease. Australian STEC epidemiology differs from many other countries, as severe outbreaks and HUS cases appear to be more often associated with non-O157 serogroups. It is not known why Australian strains of O157 STEC might differ in virulence to international strains. Here we investigate the reduced virulence of Australian strains. Multiple genetic analyses were performed, including SNP-typing, to compare the core genomes of the Australian to the international isolates, and accessory genome analysis to determine any significant differences in gene presence/absence that could be associated with their phenotypic differences in virulence. The most distinct difference between the isolates was the absence of the stx2a gene in all Australian isolates, with few other notable differences observed in the core and accessory genomes of the O157 STEC isolates analyzed in this study. The presence of stx1a in most Australian isolates was another notable observation. Acquisition of stx2a seems to coincide with the emergence of highly pathogenic STEC. Due to the lack of other notable genotypic differences observed between Australian and international isolates characterized as highly pathogenic, this may be further evidence that the absence of stx2a in Australian O157 STEC could be a significant characteristic defining its mild virulence. Further work investigating the driving force(s) behind Stx prophage loss and acquisition is needed to determine if this potential exists in Australian O157 isolates.
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Affiliation(s)
- Alexander Pintara
- Centre for Immunology and Infection Control, Queensland University of Technology, Herston, QLD, Australia
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia
| | - Amy Jennison
- Public Health Microbiology, Forensic and Scientific Services, Queensland Health, Brisbane, QLD, Australia
| | - Irani U. Rathnayake
- Public Health Microbiology, Forensic and Scientific Services, Queensland Health, Brisbane, QLD, Australia
| | - Glen Mellor
- CSIRO Animal, Food and Health Sciences, Archerfield, QLD, Australia
| | - Flavia Huygens
- Centre for Immunology and Infection Control, Queensland University of Technology, Herston, QLD, Australia
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia
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12
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Nyong EC, Zaia SR, Allué-Guardia A, Rodriguez AL, Irion-Byrd Z, Koenig SSK, Feng P, Bono JL, Eppinger M. Pathogenomes of Atypical Non-shigatoxigenic Escherichia coli NSF/SF O157:H7/NM: Comprehensive Phylogenomic Analysis Using Closed Genomes. Front Microbiol 2020; 11:619. [PMID: 32351476 PMCID: PMC7175801 DOI: 10.3389/fmicb.2020.00619] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
The toxigenic conversion of Escherichia coli strains by Shiga toxin-converting (Stx) bacteriophages were prominent and recurring events in the stepwise evolution of enterohemorrhagic E. coli (EHEC) O157:H7 from an enteropathogenic (EPEC) O55:H7 ancestor. Atypical, attenuated isolates have been described for both non-sorbitol fermenting (NSF) O157:H7 and SF O157:NM serotypes, which are distinguished by the absence of Stx, the characteristic virulence hallmark of Stx-producing E. coli (STEC). Such atypical isolates either never acquired Stx-phages or may have secondarily lost stx during the course of infection, isolation, or routine subculture; the latter are commonly referred to as LST (Lost Shiga Toxin)-isolates. In this study we analyzed the genomes of 15 NSF O157:H7 and SF O157:NM strains from North America, Europe, and Asia that are characterized by the absence of stx, the virulence hallmark of STEC. The individual genomic basis of the Stx (-) phenotype has remained largely undetermined as the majority of STEC genomes in public genome repositories were generated using short read technology and are in draft stage, posing a major obstacle for the high-resolution whole genome sequence typing (WGST). The application of LRT (long-read technology) sequencing provided us with closed genomes, which proved critical to put the atypical non-shigatoxigenic NSF O157:H7 and SF O157:NM strains into the phylogenomic context of the stepwise evolutionary model. Availability of closed chromosomes for representative Stx (-) NSF O157:H7 and SF O157:NM strains allowed to describe the genomic basis and individual evolutionary trajectories underlying the absence of Stx at high accuracy and resolution. The ability of LRT to recover and accurately assemble plasmids revealed a strong correlation between the strains' featured plasmid genotype and chromosomally inferred clade, which suggests the coevolution of the chromosome and accessory plasmids. The identified ancestral traits in the pSFO157 plasmid of NSF O157:H7 strain LSU-61 provided additional evidence for its intermediate status. Taken together, these observations highlight the utility of LRTs for advancing our understanding of EHEC O157:H7/NM pathogenome evolution. Insights into the genomic and phenotypic plasticity of STEC on a lineage- and genome-wide scale are foundational to improve and inform risk assessment, biosurveillance, and prevention strategies.
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Affiliation(s)
- Emmanuel C. Nyong
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Sam R. Zaia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Anna Allué-Guardia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Armando L. Rodriguez
- Research Computing Support Group, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Zaina Irion-Byrd
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Sara S. K. Koenig
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | | | - James L. Bono
- United States Meat Animal Research Center, Agricultural Research Service, United States Department of Agriculture (ARS-USDA), Clay Center, NE, United States
| | - Mark Eppinger
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
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Response to Questions Posed by the Food and Drug Administration Regarding Virulence Factors and Attributes that Define Foodborne Shiga Toxin-Producing Escherichia coli (STEC) as Severe Human Pathogens †. J Food Prot 2019; 82:724-767. [PMID: 30969806 DOI: 10.4315/0362-028x.jfp-18-479] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
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- NACMCF Executive Secretariat, * U.S. Department of Agriculture, Food Safety and Inspection Service, Office of Public Health Science, PP3, 9-178, 1400 Independence Avenue S.W., Washington, D.C. 20250-3700, USA
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14
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Sharma VK, Akavaram S, Schaut RG, Bayles DO. Comparative genomics reveals structural and functional features specific to the genome of a foodborne Escherichia coli O157:H7. BMC Genomics 2019; 20:196. [PMID: 30849935 PMCID: PMC6408774 DOI: 10.1186/s12864-019-5568-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 02/25/2019] [Indexed: 01/09/2023] Open
Abstract
Background Escherichia coli O157:H7 (O157) has been linked to numerous foodborne disease outbreaks. The ability to rapidly sequence and analyze genomes is important for understanding epidemiology, virulence, survival, and evolution of outbreak strains. In the current study, we performed comparative genomics to determine structural and functional features of the genome of a foodborne O157 isolate NADC 6564 and infer its evolutionary relationship to other O157 strains. Results The chromosome of NADC 6564 contained 5466 kb compared to reference strains Sakai (5498 kb) and EDL933 (5547 kb) and shared 41 of its 43 Linear Conserved Blocks (LCB) with the reference strains. However, 18 of 41 LCB had inverse orientation in NADC 6564 compared to the reference strains. NADC 6564 shared 18 of 19 bacteriophages with reference strains except that the chromosomal positioning of some of the phages differed among these strains. The additional phage (P19) of NADC 6564 was located on a 39-kb insertion element (IE) encoding several hypothetical proteins, an integrase, transposases, transcriptional regulators, an adhesin, and a phosphoethanolamine transferase (PEA). The complete homologs of the 39-kb IE were found in E. coli PCN061 of porcine origin. The IE-encoded PEA showed low homology (32–33%) to four other PEA in NADC 6564 and PEA linked to mobilizable colistin resistance in E. coli but was highly homologous (95%) to a PEA of uropathogenic, avian pathogenic, and enteroaggregative E. coli. NADC 6564 showed slightly higher minimum inhibitory concentration of colistin compared to the reference strains. The 39-kb IE also contained dndBCDE and dptFGH operons encoding DNA S-modification and a restriction pathway, linked to oxidative stress tolerance and self-defense against foreign DNA, respectively. Evolutionary tree analysis grouped NADC 6564 with lineage I O157 strains. Conclusions These results indicated that differential phage counts and different chromosomal positioning of many bacteriophages and genomic islands might have resulted in recombination events causing altered chromosomal organization in NADC 6564. Evolutionary analysis grouped NADC 6564 with lineage I strains and suggested its earlier divergence from these strains. The ability to perform S-DNA modification might affect tolerance of NADC 6564 to various stressors. Electronic supplementary material The online version of this article (10.1186/s12864-019-5568-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vijay K Sharma
- Food Safety and Enteric Pathogens Research Unit, USDA, ARS, National Animal Disease Center, 1920 Dayton Avenue, P.O. Box 70, Ames, IA, 50010, USA.
| | - Suryatej Akavaram
- Food Safety and Enteric Pathogens Research Unit, USDA, ARS, National Animal Disease Center, 1920 Dayton Avenue, P.O. Box 70, Ames, IA, 50010, USA
| | - Robert G Schaut
- Food Safety and Enteric Pathogens Research Unit, USDA, ARS, National Animal Disease Center, 1920 Dayton Avenue, P.O. Box 70, Ames, IA, 50010, USA.,Oak Ridge Institute for Science and Education (ORISE), ARS Research Participation Program, MS 36, P.O. Box 117, Oak Ridge, TN, 37831, USA
| | - Darrell O Bayles
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, ARS-USDA, Ames, Iowa, USA
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15
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The Evasive Enemy: Insights into the Virulence and Epidemiology of the Emerging Attaching and Effacing Pathogen Escherichia albertii. Infect Immun 2018; 87:IAI.00254-18. [PMID: 30373891 DOI: 10.1128/iai.00254-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 10/18/2018] [Indexed: 01/10/2023] Open
Abstract
The diarrheic attaching and effacing (A/E) pathogen Escherichia albertii was first isolated from infants in Bangladesh in 1991, although the bacterium was initially classified as Hafnia alvei Subsequent genetic and biochemical interrogation of these isolates raised concerns about their initial taxonomic placement. It was not until 2003 that these isolates were reassigned to the novel taxon Escherichia albertii because they were genetically more closely related to E. coli, although they had diverged sufficiently to warrant a novel species name. Unfortunately, new isolates continue to be mistyped as enteropathogenic E. coli (EPEC) or enterohemorrhagic E. coli (EHEC) owing to shared traits, most notably the ability to form A/E lesions. Consequently, E. albertii remains an underappreciated A/E pathogen, despite multiple reports demonstrating that many provisional EPEC and EHEC isolates incriminated in disease outbreaks are actually E. albertii Metagenomic studies on dozens of E. albertii isolates reveal a genetic architecture that boasts an arsenal of candidate virulence factors to rival that of its better-characterized cousins, EPEC and EHEC. Beyond these computational comparisons, studies addressing the regulation, structure, function, and mechanism of action of its repertoire of virulence factors are lacking. Thus, the paucity of knowledge about the epidemiology, virulence, and antibiotic resistance of E. albertii, coupled with its misclassification and its ability to develop multidrug resistance in a single step, highlights the challenges in combating this emerging pathogen. This review seeks to synthesize our current but incomplete understanding of the biology of E. albertii.
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16
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Saile N, Schuh E, Semmler T, Eichhorn I, Wieler LH, Bauwens A, Schmidt H. Determination of virulence and fitness genes associated with the pheU, pheV and selC integration sites of LEE-negative food-borne Shiga toxin-producing Escherichia coli strains. Gut Pathog 2018; 10:43. [PMID: 30337962 PMCID: PMC6174562 DOI: 10.1186/s13099-018-0271-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/01/2018] [Indexed: 01/22/2023] Open
Abstract
Background In the current study, nine foodborne “Locus of Enterocyte Effacement” (LEE)-negative Shiga toxin-producing Escherichia coli (STEC) strains were selected for whole genome sequencing and analysis for yet unknown genetic elements within the already known LEE integration sites selC, pheU and pheV. Foreign DNA ranging in size from 3.4 to 57 kbp was detected and further analyzed. Five STEC strains contained an insertion of foreign DNA adjacent to the selC tRNA gene and five and seven strains contained foreign DNA adjacent to the pheU and pheV tRNA genes, respectively. We characterized the foreign DNA insertion associated with selC (STEC O91:H21 strain 17584/1), pheU (STEC O8:H4 strain RF1a and O55:Hnt strain K30) and pheV (STEC O91:H21 strain 17584/1 and O113:H21 strain TS18/08) as examples. Results In total, 293 open reading frames partially encoding putative virulence factors such as TonB-dependent receptors, DNA helicases, a hemolysin activator protein precursor, antigen 43, anti-restriction protein KlcA, ShiA, and phosphoethanolamine transferases were detected. A virulence type IV toxin-antitoxin system was detected in three strains. Additionally, the ato system was found in one strain. In strain 17584/1 we were able to define a new genomic island which we designated GIselC17584/1. The island contained integrases and mobile elements in addition to genes for increased fitness and those playing a putative role in pathogenicity. Conclusion The data presented highlight the important role of the three tRNAs selC, pheU, and pheV for the genomic flexibility of E. coli. Electronic supplementary material The online version of this article (10.1186/s13099-018-0271-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nadja Saile
- 1Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 28, 70599 Stuttgart, Germany
| | - Elisabeth Schuh
- 1Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 28, 70599 Stuttgart, Germany.,2Department Biological Safety, National Reference Laboratory for Escherichia coli, Federal Institute for Risk Assessment (BfR), Diedersdorfer Weg 1, 12277 Berlin, Germany
| | | | - Inga Eichhorn
- 4Institute of Microbiology and Epizootics, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163 Berlin, Germany
| | | | - Andreas Bauwens
- 5Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149 Münster, Germany
| | - Herbert Schmidt
- 1Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 28, 70599 Stuttgart, Germany
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Abstract
σN (also σ54) is an alternative sigma factor subunit of the RNA polymerase complex that regulates the expression of genes from many different ontological groups. It is broadly conserved in the Eubacteria with major roles in nitrogen metabolism, membrane biogenesis, and motility. σN is encoded as the first gene of a five-gene operon including rpoN (σN), ptsN, hpf, rapZ, and npr that has been genetically retained among species of Escherichia, Shigella, and Salmonella. In an increasing number of bacteria, σN has been implicated in the control of genes essential to pathogenic behavior, including those involved in adherence, secretion, immune subversion, biofilm formation, toxin production, and resistance to both antimicrobials and biological stressors. For most pathogens how this is achieved is unknown. In enterohemorrhagic Escherichia coli (EHEC) O157, Salmonella enterica, and Borrelia burgdorferi, regulation of virulence by σN requires another alternative sigma factor, σS, yet the model by which σN-σS virulence regulation is predicted to occur is varied in each of these pathogens. In this review, the importance of σN to bacterial pathogenesis is introduced, and common features of σN-dependent virulence regulation discussed. Emphasis is placed on the molecular mechanisms underlying σN virulence regulation in E. coli O157. This includes a review of the structure and function of regulatory pathways connecting σN to virulence expression, predicted input signals for pathway stimulation, and the role for cognate σN activators in initiation of gene systems determining pathogenic behavior.
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18
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Krause M, Barth H, Schmidt H. Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli. Toxins (Basel) 2018; 10:toxins10060241. [PMID: 29903982 PMCID: PMC6024878 DOI: 10.3390/toxins10060241] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/07/2018] [Accepted: 06/12/2018] [Indexed: 12/16/2022] Open
Abstract
Studies on Shiga toxin-producing Escherichia coli (STEC) typically examine and classify the virulence gene profiles based on genomic analyses. Among the screened strains, a subgroup of STEC which lacks the locus of enterocyte effacement (LEE) has frequently been identified. This raises the question about the level of pathogenicity of such strains. This review focuses on the advantages and disadvantages of the standard screening procedures in virulence profiling and summarizes the current knowledge concerning the function and regulation of toxins encoded by LEE-negative STEC. Although LEE-negative STEC usually come across as food isolates, which rarely cause infections in humans, some serotypes have been implicated in human diseases. In particular, the LEE-negative E. coli O104:H7 German outbreak strain from 2011 and the Australian O113:H21 strain isolated from a HUS patient attracted attention. Moreover, the LEE-negative STEC O113:H21 strain TS18/08 that was isolated from minced meat is remarkable in that it not only encodes multiple toxins, but in fact expresses three different toxins simultaneously. Their characterization contributes to understanding the virulence of the LEE-negative STEC.
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Affiliation(s)
- Maike Krause
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany.
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany.
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19
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Abraham S, Kirkwood RN, Laird T, Saputra S, Mitchell T, Singh M, Linn B, Abraham RJ, Pang S, Gordon DM, Trott DJ, O'Dea M. Dissemination and persistence of extended-spectrum cephalosporin-resistance encoding IncI1-bla CTXM-1 plasmid among Escherichia coli in pigs. ISME JOURNAL 2018; 12:2352-2362. [PMID: 29899511 PMCID: PMC6155088 DOI: 10.1038/s41396-018-0200-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/24/2018] [Accepted: 03/12/2018] [Indexed: 01/09/2023]
Abstract
This study investigated the ecology, epidemiology and plasmid characteristics of extended-spectrum cephalosporin (ESC)-resistant E. coli in healthy pigs over a period of 4 years (2013–2016) following the withdrawal of ESCs. High carriage rates of ESC-resistant E. coli were demonstrated in 2013 (86.6%) and 2014 (83.3%), compared to 2015 (22%) and 2016 (8.5%). ESC resistance identified among E. coli isolates was attributed to the carriage of an IncI1 ST-3 plasmid (pCTXM1-MU2) encoding blaCTXM-1. Genomic characterisation of selected E. coli isolates (n = 61) identified plasmid movement into multiple commensal E. coli (n = 22 STs). Major STs included ST10, ST5440, ST453, ST2514 and ST23. A subset of the isolates belong to the atypical enteropathogenic E. coli (aEPEC) pathotype that harboured multiple LEE pathogenic islands. pCTXM1-MU2 was similar (99% nt identity) to IncI1-ST3 plasmids reported from Europe, encoded resistance to aminoglycosides, sulphonamides and trimethoprim, and carried colicin Ib. pCTXM1-MU2 appears to be highly stable and readily transferable. This study demonstrates that ESC resistance may persist for a protracted period following removal of direct selection pressure, resulting in the emergence of ESC-resistance in both commensal E. coli and aEPEC isolates of potential significance to human and animal health.
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Affiliation(s)
- Sam Abraham
- Antimicrobial Resistance and Infectious Diseases Laboratory, School of Veterinary and Life Sciences, Murdoch University, Melbourne, Western Australia, Australia.
| | - Roy N Kirkwood
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, Australia.,Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia
| | - Tanya Laird
- Antimicrobial Resistance and Infectious Diseases Laboratory, School of Veterinary and Life Sciences, Murdoch University, Melbourne, Western Australia, Australia
| | - Sugiyono Saputra
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, Australia.,Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia.,Research Center for Biology, Indonesian Institute of Sciences, West Java, Cibinong, Indonesia
| | - Tahlia Mitchell
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, Australia.,Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia
| | - Mohinder Singh
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, Australia.,Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia
| | - Benjamin Linn
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, Australia.,Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia
| | - Rebecca J Abraham
- Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia
| | - Stanley Pang
- Antimicrobial Resistance and Infectious Diseases Laboratory, School of Veterinary and Life Sciences, Murdoch University, Melbourne, Western Australia, Australia
| | - David M Gordon
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, Australia
| | - Darren J Trott
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, Australia.,Australian Centre for Antimicrobial Resistance Ecology, University of Adelaide, Adelaide, Australia
| | - Mark O'Dea
- Antimicrobial Resistance and Infectious Diseases Laboratory, School of Veterinary and Life Sciences, Murdoch University, Melbourne, Western Australia, Australia
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Douëllou T, Galia W, Kerangart S, Marchal T, Milhau N, Bastien R, Bouvier M, Buff S, Montel MC, Sergentet-Thevenot D. Milk Fat Globules Hamper Adhesion of Enterohemorrhagic Escherichia coli to Enterocytes: In Vitro and in Vivo Evidence. Front Microbiol 2018; 9:947. [PMID: 29867855 PMCID: PMC5963252 DOI: 10.3389/fmicb.2018.00947] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/23/2018] [Indexed: 12/13/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC; E. coli) are food-borne agents associated with gastroenteritis, enterocolitis, bloody diarrhea and the hemolytic-uremic syndrome (HUS). Bovine milk glycans have been shown to contain oligosaccharides which are similar to host epithelial cell receptors and can therefore prevent bacterial adhesion. This study aimed to describe interactions between EHEC O157:H7 EDL933 and O26:H11 21765 and milk fat globules (MFGs) in raw milk and raw milk cheese, and the impact of MFGs on EHEC strains adhesion to the intestinal tract in vitro and in vivo. Both EHEC serotypes clearly associated with native bovine MFGs and significantly limited their adhesion to a co-culture of intestinal cells. The presence of MFGs in raw milk cheese had two effects on the adhesion of both EHEC serotypes to the intestinal tracts of streptomycin-treated mice. First, it delayed and reduced EHEC excretion in mouse feces for both strains. Second, the prime implantation site for both EHEC strains was 6 cm more proximal in the intestinal tracts of mice fed with contaminated cheese containing less than 5% of fat than in those fed with contaminated cheese containing 40% of fat. Feeding mice with 40% fat cheese reduced the intestinal surface contaminated with EHEC and may therefore decrease severity of illness.
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Affiliation(s)
- Thomas Douëllou
- Institut National de Recherche Agronomique, Unité de Recherches Fromagères, Aurillac, France.,Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France
| | - Wessam Galia
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France
| | - Stéphane Kerangart
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France
| | - Thierry Marchal
- UPSP ICE 2011.03.101 & CRB ANIM (ANR11.INBS.0003), Université de Lyon, VetAgro Sup, Marcy-l'Étoile, France
| | - Nadège Milhau
- UPSP ICE 2011.03.101 & CRB ANIM (ANR11.INBS.0003), Université de Lyon, VetAgro Sup, Marcy-l'Étoile, France
| | - Renaud Bastien
- Department of Collective Behaviour, Max Planck Institute for Ornithology, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Marion Bouvier
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France.,Laboratoire d'Études des Microorganismes Alimentaires Pathogènes - French National Reference Laboratory for Escherichia coli Including Shiga Toxin Producing E. coli, Université de Lyon, VetAgro Sup Campus Vétérinaire, Marcy-l'Étoile, France
| | - Samuel Buff
- UPSP ICE 2011.03.101 & CRB ANIM (ANR11.INBS.0003), Université de Lyon, VetAgro Sup, Marcy-l'Étoile, France
| | - Marie-Christine Montel
- Institut National de Recherche Agronomique, Unité de Recherches Fromagères, Aurillac, France
| | - Delphine Sergentet-Thevenot
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France.,Laboratoire d'Études des Microorganismes Alimentaires Pathogènes - French National Reference Laboratory for Escherichia coli Including Shiga Toxin Producing E. coli, Université de Lyon, VetAgro Sup Campus Vétérinaire, Marcy-l'Étoile, France
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21
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Regulation of the Locus of Enterocyte Effacement in Attaching and Effacing Pathogens. J Bacteriol 2017; 200:JB.00336-17. [PMID: 28760850 DOI: 10.1128/jb.00336-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Attaching and effacing (AE) pathogens colonize the gut mucosa using a type three secretion system (T3SS) and a suite of effector proteins. The locus of enterocyte effacement (LEE) is the defining genetic feature of the AE pathogens, encoding the T3SS and the core effector proteins necessary for pathogenesis. Extensive research has revealed a complex regulatory network that senses and responds to a myriad of host- and microbiota-derived signals in the infected gut to control transcription of the LEE. These signals include microbiota-liberated sugars and metabolites in the gut lumen, molecular oxygen at the gut epithelium, and host hormones. Recent research has revealed that AE pathogens also recognize physical signals, such as attachment to the epithelium, and that the act of effector translocation remodels gene expression in infecting bacteria. In this review, we summarize our knowledge to date and present an integrated view of how chemical, geographical, and physical cues regulate the virulence program of AE pathogens during infection.
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22
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Shiga Toxin (Verotoxin)-producing
Escherichia coli and Foodborne Disease:
A Review. Food Saf (Tokyo) 2017; 5:35-53. [PMID: 32231928 DOI: 10.14252/foodsafetyfscj.2016029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/31/2017] [Indexed: 12/22/2022] Open
Abstract
Shiga toxin (verotoxin)-producing Escherichia coli (STEC) is an important cause of foodborne disease. Since outcomes of the infections with STEC have a broad range of manifestation from asymptomatic infection or mild intestinal discomfort, to bloody diarrhea, hemolytic uremic syndrome (HUS), end-stage renal disease (ESRD), and death, the disease is a serious burden in public health and classified as a notifiable infectious disease in many countries. Cattle and other ruminants are considered to be the major reservoirs of STEC though isolation of STEC from other animals have been reported. Hence, the source of contamination extends to a wide range of foods, not only beef products but also fresh produce, water, and environment contaminated by excretes from the animals, mainly cattle. A low- infectious dose of STEC makes the disease relatively contagious, and causes outbreaks with unknown contamination sources and, therefore, as a preventive measure against STEC infection, it is important to obtain characteristics of prevailing STEC isolates in the region through robust surveillance. Analysis of the isolates by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA) could help finding unrecognized foodborne outbreaks due to consumption of respective contaminated sources. However, though the results of molecular analysis of the isolates could indicate linkage of sporadic cases of STEC infection, it is hardly concluded that the cases are related via contaminated food source if it were not for epidemiological information. Therefore, it is essential to combine the results of strain analysis and epidemiological investigation rapidly to detect rapidly foodborne outbreaks caused by bacteria. This article reviews STEC infection as foodborne disease and further discusses key characteristics of STEC including pathogenesis, clinical manifestation, prevention and control of STEC infection. We also present the recent situation of the disease in Japan based on the surveillance of STEC infection.
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Bunnell BE, Escobar JF, Bair KL, Sutton MD, Crane JK. Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli. PLoS One 2017; 12:e0178303. [PMID: 28542496 PMCID: PMC5440055 DOI: 10.1371/journal.pone.0178303] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/10/2017] [Indexed: 01/22/2023] Open
Abstract
Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx) and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.
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Affiliation(s)
- Bryan E. Bunnell
- Department of Medicine, Division of Infectious Diseases, University at Buffalo, Buffalo, NY, United States of America
| | - Jillian F. Escobar
- Department of Medicine, Division of Infectious Diseases, University at Buffalo, Buffalo, NY, United States of America
| | - Kirsten L. Bair
- Department of Medicine, Division of Infectious Diseases, University at Buffalo, Buffalo, NY, United States of America
| | - Mark D. Sutton
- Department of Biochemistry, University at Buffalo, Buffalo, NY, United States of America
| | - John K. Crane
- Department of Medicine, Division of Infectious Diseases, University at Buffalo, Buffalo, NY, United States of America
- * E-mail:
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Development of an HTS system to identify natural chemicals that specifically inhibit Escherichia coli O157:H7 adhesion to host cells. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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25
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Gaytán MO, Martínez-Santos VI, Soto E, González-Pedrajo B. Type Three Secretion System in Attaching and Effacing Pathogens. Front Cell Infect Microbiol 2016; 6:129. [PMID: 27818950 PMCID: PMC5073101 DOI: 10.3389/fcimb.2016.00129] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/27/2016] [Indexed: 02/06/2023] Open
Abstract
Enteropathogenic Escherichia coli and enterohemorrhagic E. coli are diarrheagenic bacterial human pathogens that cause severe gastroenteritis. These enteric pathotypes, together with the mouse pathogen Citrobacter rodentium, belong to the family of attaching and effacing pathogens that form a distinctive histological lesion in the intestinal epithelium. The virulence of these bacteria depends on a type III secretion system (T3SS), which mediates the translocation of effector proteins from the bacterial cytosol into the infected cells. The core architecture of the T3SS consists of a multi-ring basal body embedded in the bacterial membranes, a periplasmic inner rod, a transmembrane export apparatus in the inner membrane, and cytosolic components including an ATPase complex and the C-ring. In addition, two distinct hollow appendages are assembled on the extracellular face of the basal body creating a channel for protein secretion: an approximately 23 nm needle, and a filament that extends up to 600 nm. This filamentous structure allows these pathogens to get through the host cells mucus barrier. Upon contact with the target cell, a translocation pore is assembled in the host membrane through which the effector proteins are injected. Assembly of the T3SS is strictly regulated to ensure proper timing of substrate secretion. The different type III substrates coexist in the bacterial cytoplasm, and their hierarchical secretion is determined by specialized chaperones in coordination with two molecular switches and the so-called sorting platform. In this review, we present recent advances in the understanding of the T3SS in attaching and effacing pathogens.
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Affiliation(s)
- Meztlli O Gaytán
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Verónica I Martínez-Santos
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Eduardo Soto
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
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Lin IT, Chiou YM, Liang YC, Lin CN, Sun WSW, Li S, Chang CH, Syu WJ, Chen JW. Unique clustering genes in the bacterial chromosome affecting the type-III secretion of enterohaemorrhagic Escherichia coli. Microbiology (Reading) 2016; 162:1744-1754. [DOI: 10.1099/mic.0.000348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- I-Ting Lin
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Yi-Ming Chiou
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Yen-Chia Liang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Ching-Nan Lin
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Wei-Sheng W. Sun
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Shiaowen Li
- Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Chuan-Hsiung Chang
- Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Wan-Jr Syu
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Jenn-Wei Chen
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
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Ferdous M, Kooistra-Smid AMD, Zhou K, Rossen JWA, Friedrich AW. Virulence, Antimicrobial Resistance Properties and Phylogenetic Background of Non-H7 Enteropathogenic Escherichia coli O157. Front Microbiol 2016; 7:1540. [PMID: 27733849 PMCID: PMC5039186 DOI: 10.3389/fmicb.2016.01540] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/14/2016] [Indexed: 02/02/2023] Open
Abstract
Escherichia coli (E.coli) O157 that do not produce Shiga toxin and do not possess flagellar antigen H7 are of diverse H serotypes. In this study, the antibiotic resistance properties, genotype of a set of virulence associated genes and the phylogenetic background of E. coli O157:non-H7 groups were compared. Whole genome sequencing was performed on fourteen O157:non-H7 isolates collected in the STEC-ID-net study. The genomes were compared with E. coli O157 genomes and a typical Enteropathogenic E. coli (tEPEC) genome downloaded from NCBI. Twenty-six (86%) of the analyzed genomes had the intimin encoding gene eae but of different types mostly correlating with their H types, e.g., H16, H26, H39, and H45 carried intimin type ε, β, κ, and α, respectively. They belonged to several E. coli phylogenetic groups, i.e., to phylogenetic group A, B1, B2, and D. Seven (50%) of our collected O157:non-H7 isolates were resistant to two or more antibiotics. Several mobile genetic elements, such as plasmids, insertion elements, and pathogenicity islands, carrying a set of virulence and resistance genes were found in the E. coli O157:non-H7 isolates. Core genome phylogenetic analysis showed that O157:non-H7 isolates probably evolved from different phylogenetic lineages and were distantly related to the E. coli O157:H7 lineage. We hypothesize that independent acquisition of mobile genetic elements by isolates of different lineages have contributed to the different molecular features of the O157:non-H7 strains. Although distantly related to the STEC O157, E. coli O157:non-H7 isolates from multiple genetic background could be considered as pathogen of concern for their diverse virulence and antibiotic resistance properties.
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Affiliation(s)
- Mithila Ferdous
- Department of Medical Microbiology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Anna M D Kooistra-Smid
- Department of Medical Microbiology, University Medical Center Groningen, University of GroningenGroningen, Netherlands; Department of Medical Microbiology, Certe Laboratory for Infectious DiseasesGroningen, Netherlands
| | - Kai Zhou
- Department of Medical Microbiology, University Medical Center Groningen, University of GroningenGroningen, Netherlands; State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Centre for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou, China
| | - John W A Rossen
- Department of Medical Microbiology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Alexander W Friedrich
- Department of Medical Microbiology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
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Abstract
The H-NS family of DNA-binding proteins is the subject of intense study due to its important roles in the regulation of horizontally acquired genes critical for virulence, antibiotic resistance, and metabolism. Xenogeneic silencing proteins, typified by the H-NS protein of Escherichia coli, specifically target and downregulate expression from AT-rich genes by selectively recognizing specific structural features unique to the AT-rich minor groove. In doing so, these proteins facilitate bacterial evolution; enabling these cells to engage in horizontal gene transfer while buffering potential any detrimental fitness consequences that may result from it. Xenogeneic silencing and counter-silencing explain how bacterial cells can evolve effective gene regulatory strategies in the face of rampant gene gain and loss and it has extended our understanding of bacterial gene regulation beyond the classic operon model. Here we review the structures and mechanisms of xenogeneic silencers as well as their impact on bacterial evolution. Several H-NS-like proteins appear to play a role in facilitating gene transfer by other mechanisms including by regulating transposition, conjugation, and participating in the activation of virulence loci like the locus of enterocyte effacement pathogenicity island of pathogenic strains of E. coli. Evidence suggests that the critical determinants that dictate whether an H-NS-like protein will be a silencer or will perform a different function do not lie in the DNA-binding domain but, rather, in the domains that control oligomerization. This suggests that H-NS-like proteins are transcription factors that both recognize and alter the shape of DNA to exert specific effects that include but are not limited to gene silencing.
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Bernedo-Navarro RA, Yano T. Phage display and Shiga toxin neutralizers. Toxicon 2016; 113:60-9. [DOI: 10.1016/j.toxicon.2016.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 02/03/2016] [Accepted: 02/11/2016] [Indexed: 02/01/2023]
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The Locus of Enterocyte Effacement and Associated Virulence Factors of Enterohemorrhagic Escherichia coli. Microbiol Spectr 2016; 2:EHEC-0007-2013. [PMID: 26104209 DOI: 10.1128/microbiolspec.ehec-0007-2013] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A subset of Shiga toxin-producing Escherichia coli strains, termed enterohemorrhagic E. coli (EHEC), is defined in part by the ability to produce attaching and effacing (A/E) lesions on intestinal epithelia. Such lesions are characterized by intimate bacterial attachment to the apical surface of enterocytes, cytoskeletal rearrangements beneath adherent bacteria, and destruction of proximal microvilli. A/E lesion formation requires the locus of enterocyte effacement (LEE), which encodes a Type III secretion system that injects bacterial proteins into host cells. The translocated proteins, termed effectors, subvert a plethora of cellular pathways to the benefit of the pathogen, for example, by recruiting cytoskeletal proteins, disrupting epithelial barrier integrity, and interfering with the induction of inflammation, phagocytosis, and apoptosis. The LEE and selected effectors play pivotal roles in intestinal persistence and virulence of EHEC, and it is becoming clear that effectors may act in redundant, synergistic, and antagonistic ways during infection. Vaccines that target the function of the Type III secretion system limit colonization of reservoir hosts by EHEC and may thus aid control of zoonotic infections. Here we review the features and functions of the LEE-encoded Type III secretion system and associated effectors of E. coli O157:H7 and other Shiga toxin-producing E. coli strains.
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Contributions of EspA Filaments and Curli Fimbriae in Cellular Adherence and Biofilm Formation of Enterohemorrhagic Escherichia coli O157:H7. PLoS One 2016; 11:e0149745. [PMID: 26900701 PMCID: PMC4764202 DOI: 10.1371/journal.pone.0149745] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 02/04/2016] [Indexed: 12/14/2022] Open
Abstract
In Escherichia coli O157:H7 (O157), the filamentous structure of the type III secretion system is produced from the polymerization of the EspA protein. EspA filaments are essential for O157 adherence to epithelial cells. In previous studies, we demonstrated that O157 hha deletion mutants showed increased adherence to HEp-2 cells and produced abundant biofilms. Transcriptional analysis revealed increased expression of espA as well as the csgA gene, which encodes curli fimbriae that are essential for biofilm formation. In the present study, we constructed hha espA, hha csgA, and hha csgA espA deletion mutants to determine the relative importance of EspA and CsgA in O157 adherence to HEp-2 cells and biofilm formation. In vitro adherence assays, conducted at 37°C in a tissue culture medium containing 0.1% glucose, showed that HEp-2 cell adherence required EspA because hha espA and hha csgA espA mutants adhered to HEp-2 cells at higher levels only when complemented with an espA-expressing plasmid. Biofilm assays performed at 28°C in a medium lacking glucose showed dependency of biofilm formation on CsgA; however EspA was not produced under these conditions. Despite production of detectable levels of EspA at 37°C in media supplemented with 0.1% glucose, the biofilm formation occurred independent of EspA. These results indicate dependency of O157 adherence to epithelial cells on EspA filaments, while CsgA promoted biofilm formation under conditions mimicking those found in the environment (low temperature with nutrient limitations) and in the digestive tract of an host animal (higher temperature and low levels of glucose).
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De la Cruz MA, Morgan JK, Ares MA, Yáñez-Santos JA, Riordan JT, Girón JA. The Two-Component System CpxRA Negatively Regulates the Locus of Enterocyte Effacement of Enterohemorrhagic Escherichia coli Involving σ(32) and Lon protease. Front Cell Infect Microbiol 2016; 6:11. [PMID: 26904510 PMCID: PMC4742615 DOI: 10.3389/fcimb.2016.00011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/18/2016] [Indexed: 12/05/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a significant cause of serious human gastrointestinal disease worldwide. EHEC strains contain a pathogenicity island called the locus of enterocyte effacement (LEE), which encodes virulence factors responsible for damaging the gut mucosa. The Cpx envelope stress response of E. coli is controlled by a two-component system (TCS) consisting of a sensor histidine kinase (CpxA) and a cytoplasmic response regulator (CpxR). In this study, we investigated the role of CpxRA in the expression of LEE-encoded virulence factors of EHEC. We found that a mutation in cpxA significantly affected adherence of EHEC to human epithelial cells. Analysis of this mutant revealed the presence of high levels of CpxR which repressed transcription of grlA and ler, the main positive virulence regulators of the LEE, and influenced negatively the production of the type 3 secretion system–associated EspABD translocator proteins. It is known that CpxR activates rpoH (Sigma factor 32), which in turns activates transcription of the lon protease gene. We found that transcription levels of ler and grlA were significantly increased in the lon and cpxA lon mutants suggesting that lon is involved in down-regulating LEE genes. In addition, the Galleria mellonella model of infection was used to analyze the effect of the loss of the cpx and lon genes in EHEC's ability to kill the larvae. We found that the cpxA mutant was significantly deficient at killing the larvae however, the cpxA lon mutant which overexpresses LEE genes in vitro, was unable to kill the larvae, suggesting that virulence in the G. mellonella model is T3SS independent and that CpxA modulates virulence through a yet unknown EHEC-specific factor. Our data provides new insights and broadens our scope into the complex regulatory network of the LEE in which the CpxA sensor kinase plays an important role in a cascade involving both global and virulence regulators.
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Affiliation(s)
- Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI-IMSSMexico City, Mexico; Emerging Pathogens Institute, University of FloridaGainesville, FL, USA
| | - Jason K Morgan
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida Tampa, FL, USA
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI-IMSS Mexico City, Mexico
| | - Jorge A Yáñez-Santos
- Facultad de Estomatología, Benemerita Universidad Autonoma de Puebla Puebla, Mexico
| | - James T Riordan
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida Tampa, FL, USA
| | - Jorge A Girón
- Emerging Pathogens Institute, University of FloridaGainesville, FL, USA; Centro de Deteccion Biomolecular, Benemerita Universidad Autonoma de PueblaPuebla, Mexico
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Genomic diversity of EPEC associated with clinical presentations of differing severity. Nat Microbiol 2016; 1:15014. [PMID: 27571975 DOI: 10.1038/nmicrobiol.2015.14] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/06/2015] [Indexed: 01/01/2023]
Abstract
Enteropathogenic Escherichia coli (EPEC) are diarrhoeagenic E. coli, and are a significant cause of gastrointestinal illness among young children in developing countries. Typical EPEC are identified by the presence of the bundle-forming pilus encoded by a virulence plasmid, which has been linked to an increased severity of illness, while atypical EPEC lack this feature. Comparative genomics of 70 total EPEC from lethal (LI), non-lethal symptomatic (NSI) or asymptomatic (AI) cases of diarrhoeal illness in children enrolled in the Global Enteric Multicenter Study was used to investigate the genomic differences in EPEC isolates obtained from individuals with various clinical outcomes. A comparison of the genomes of isolates from different clinical outcomes identified genes that were significantly more prevalent in EPEC isolates of symptomatic and lethal outcomes than in EPEC isolates of asymptomatic outcomes. These EPEC isolates exhibited previously unappreciated phylogenomic diversity and combinations of virulence factors. These comparative results highlight the diversity of the pathogen, as well as the complexity of the EPEC virulence factor repertoire.
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Is Shiga Toxin-Negative Escherichia coli O157:H7 Enteropathogenic or Enterohemorrhagic Escherichia coli? Comprehensive Molecular Analysis Using Whole-Genome Sequencing. J Clin Microbiol 2015; 53:3530-8. [PMID: 26311863 PMCID: PMC4609726 DOI: 10.1128/jcm.01899-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 08/20/2015] [Indexed: 12/24/2022] Open
Abstract
The ability of Escherichia coli O157:H7 to induce cellular damage leading to disease in humans is related to numerous virulence factors, most notably the stx gene, encoding Shiga toxin (Stx) and carried by a bacteriophage. Loss of the Stx-encoding bacteriophage may occur during infection or culturing of the strain. Here, we collected stx-positive and stx-negative variants of E. coli O157:H7/NM (nonmotile) isolates from patients with gastrointestinal complaints. Isolates were characterized by whole-genome sequencing (WGS), and their virulence properties and phylogenetic relationship were determined. Because of the presence of the eae gene but lack of the bfpA gene, the stx-negative isolates were considered atypical enteropathogenic E. coli (aEPEC). However, they had phenotypic characteristics similar to those of the Shiga toxin-producing E. coli (STEC) isolates and belonged to the same sequence type, ST11. Furthermore, EPEC and STEC isolates shared similar virulence genes, the locus of enterocyte effacement region, and plasmids. Core genome phylogenetic analysis using a gene-by-gene typing approach showed that the sorbitol-fermenting (SF) stx-negative isolates clustered together with an SF STEC isolate and that one non-sorbitol-fermenting (NSF) stx-negative isolate clustered together with NSF STEC isolates. Therefore, these stx-negative isolates were thought either to have lost the Stx phage or to be a progenitor of STEC O157:H7/NM. As detection of STEC infections is often based solely on the identification of the presence of stx genes, these may be misdiagnosed in routine laboratories. Therefore, an improved diagnostic approach is required to manage identification, strategies for treatment, and prevention of transmission of these potentially pathogenic strains.
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Amin AS, Hsu CY, Darwish SF, Ghosh P, AbdEl-Fatah EM, Behour TS, Talaat AM. Ecology and genomic features of infection with Mycobacterium avium subspecies paratuberculosis in Egypt. MICROBIOLOGY-SGM 2015; 161:807-18. [PMID: 25667007 DOI: 10.1099/mic.0.000051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 02/02/2015] [Indexed: 01/27/2023]
Abstract
Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) is the causative agent of paratuberculosis, or Johne's disease, in cattle, with potential involvement in cases of Crohn's disease in humans. Johne's disease is found worldwide and is economically important for both beef and dairy industries. In an effort to characterize this important infection in Egypt, we analysed the ecological and genomic features of recent isolates of M. paratuberculosis. In this report, we examined 26 Holstein dairy herds distributed throughout Egypt, from 2010 to 2013. Using PCR analysis of faecal samples, we estimated a mean herd-level prevalence of 65.4 %, with animal-level infection that reached a mean of 13.6 % among animals suffering from diarrhoea. Whole genome sequencing of field isolates identified numerous single nucleotide polymorphisms among field isolates relative to the standard M. paratuberculosis K10 genome. Interestingly, the virulence of M. paratuberculosis isolates from Egypt revealed diverse virulence phenotypes in the murine model of paratuberculosis, with significant differences in tissue colonization, particularly during the chronic stage of infection. Overall, our analysis confirmed that Johne's disease is a newly identified problem in Egypt and indicated that M. paratuberculosis has potentially diverse genotypes that impact its virulence. Further ecological mapping and genomic analysis of M. paratuberculosis will enhance our understanding of the transmission and evolutionary dynamics of this pathogen under natural field conditions.
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Affiliation(s)
- Adel S Amin
- Biotechnology Research Unit, Animal Reproduction Research Institute (ARRI), Giza, Egypt
| | - Chung-Yi Hsu
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Samah F Darwish
- Biotechnology Research Unit, Animal Reproduction Research Institute (ARRI), Giza, Egypt
| | - Pallab Ghosh
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Eman M AbdEl-Fatah
- Biotechnology Research Unit, Animal Reproduction Research Institute (ARRI), Giza, Egypt
| | - Tahani S Behour
- Biotechnology Research Unit, Animal Reproduction Research Institute (ARRI), Giza, Egypt
| | - Adel M Talaat
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA Department of Food Hygiene and Control, Faculty of Veterinary Medicine Cairo University, Giza, Egypt
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Abstract
Adhesins are a group of proteins in enterohemorrhagic Escherichia coli (EHEC) that are involved in the attachment or colonization of this pathogen to abiotic (plastic or steel) and biological surfaces, such as those found in bovine and human intestines. This review provides the most up-to-date information on these essential adhesion factors, summarizing important historical discoveries and analyzing the current and future state of this research. In doing so, the proteins intimin and Tir are discussed in depth, especially regarding their role in the development of attaching and effacing lesions and in EHEC virulence. Further, a series of fimbrial proteins (Lpf1, Lpf2, curli, ECP, F9, ELF, Sfp, HCP, and type 1 fimbriae) are also described, emphasizing their various contributions to adherence and colonization of different surfaces and their potential use as genetic markers in detection and classification of different EHEC serotypes. This review also discusses the role of several autotransporter proteins (EhaA-D, EspP, Saa and Sab, and Cah), as well as other proteins associated with adherence, such as flagella, EibG, Iha, and OmpA. While these proteins have all been studied to varying degrees, all of the adhesins summarized in this chapter have been linked to different stages of the EHEC life cycle, making them good targets for the development of more effective diagnostics and therapeutics.
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Affiliation(s)
- Brian D. McWilliams
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, 77555. USA
| | - Alfredo G. Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, 77555. USA
- Department of Pathology and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, 77555. USA
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Morgan JK, Ortiz JA, Riordan JT. The role for TolA in enterohemorrhagic Escherichia coli pathogenesis and virulence gene transcription. Microb Pathog 2014; 77:42-52. [DOI: 10.1016/j.micpath.2014.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/14/2014] [Accepted: 10/21/2014] [Indexed: 01/16/2023]
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Tobe T, Yen H, Takahashi H, Kagayama Y, Ogasawara N, Oshima T. Antisense transcription regulates the expression of the enterohemorrhagic Escherichia coli virulence regulatory gene ler in response to the intracellular iron concentration. PLoS One 2014; 9:e101582. [PMID: 25006810 PMCID: PMC4090186 DOI: 10.1371/journal.pone.0101582] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/08/2014] [Indexed: 12/12/2022] Open
Abstract
Enteric pathogens, such as enterohemorrhagic E. coli (EHEC) O157:H7, encounter varying concentrations of iron during their life cycle. In the gastrointestinal tract, the amount of available free iron is limited because of absorption by host factors. EHEC and other enteric pathogens have developed sophisticated iron-responsive systems to utilize limited iron resources, and these systems are primarily regulated by the Fur repressor protein. The iron concentration could be a signal that controls gene expression in the intestines. In this study, we explored the role of iron in LEE (locus for enterocyte effacement) virulence gene expression in EHEC. In contrast to the expression of Fur-regulated genes, the expression of LEE genes was greatly reduced in fur mutants irrespective of the iron concentration. The expression of the ler gene, the LEE-encoded master regulator, was affected at a post-transcription step by fur mutation. Further analysis showed that the loss of Fur affected the translation of the ler gene by increasing the intracellular concentration of free iron, and the transcription of the antisense strand was necessary for regulation. The results indicate that LEE gene expression is closely linked to the control of intracellular free iron homeostasis.
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Affiliation(s)
- Toru Tobe
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- * E-mail:
| | - Hilo Yen
- Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, Chiba, Chiba, Japan
| | - Yoko Kagayama
- Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Naotake Ogasawara
- Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Taku Oshima
- Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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Mitra A, Fay PA, Vendura KW, Alla Z, Carroll RK, Shaw LN, Riordan JT. σ(N) -dependent control of acid resistance and the locus of enterocyte effacement in enterohemorrhagic Escherichia coli is activated by acetyl phosphate in a manner requiring flagellar regulator FlhDC and the σ(S) antagonist FliZ. Microbiologyopen 2014; 3:497-512. [PMID: 24931910 PMCID: PMC4287178 DOI: 10.1002/mbo3.183] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 04/30/2014] [Accepted: 05/15/2014] [Indexed: 12/02/2022] Open
Abstract
In enterohemorrhagic Escherichia coli (EHEC), sigma factor N (σN) regulates glutamate-dependent acid resistance (GDAR) and the locus of enterocyte effacement (LEE); discrete genetic systems that are required for transmission and virulence of this intestinal pathogen. Regulation of these systems requires nitrogen regulatory protein C, NtrC, and is a consequence of NtrC-σN-dependent reduction in the activity of sigma factor S (σS). This study elucidates pathway components and stimuli for σN-directed regulation of GDAR and the LEE in EHEC. Deletion of fliZ, the product of which reduces σS activity, phenocopied rpoN (σN) and ntrC null strains for GDAR and LEE control, acid resistance, and adherence. Upregulation of fliZ by NtrC-σN was shown to be indirect and required an intact flagellar regulator flhDC. Activation of flhDC by NtrC-σN and FlhDC-dependent regulation of GDAR and the LEE was dependent on σN-promoter flhDP2, and a newly described NtrC upstream activator sequence. Addition of ammonium chloride significantly altered expression of GDAR and LEE, acid resistance, and adherence, independently of rpoN, ntrC, and the NtrC sensor kinase, ntrB. Altering the availability of NtrC phosphodonor acetyl phosphate by growth without glucose, with acetate addition, or by deletion of acetate kinase ackA, abrogated NtrC-σN-dependent control of flhDC, fliZ, GDAR, and the LEE.
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Affiliation(s)
- Avishek Mitra
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida, 33620
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Kumar A, Taneja N, Sharma M. An epidemiological and environmental study of Shiga toxin-producing Escherichia coli in India. Foodborne Pathog Dis 2014; 11:439-46. [PMID: 24796582 DOI: 10.1089/fpd.2013.1613] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens of worldwide importance, but a shortage of data exists for STEC isolation from India. Therefore, an epidemiological and environmental study that covers a large geographic area in north India was conducted. Ruminant stool samples (n=650) were collected from 59 dairies. Meat samples (n=450) were collected from local abattoirs and the main slaughterhouse of the region. Additionally, 600 human cases of diarrhea and hemolytic uremic syndrome were screened for STEC. Isolates were characterized for the virulence gene profiles and for the serogroups and were submitted to molecular typing by the multilocus variable-number tandem-repeat analysis (MLVA). Overall, 12.3% of animal stool samples and 6.3% of mutton samples (n=160) were positive for STEC. Additionally, STEC were isolated from 1.7% and 1.6% of watery (n=290) and bloody (n=310) stool specimens, respectively. Animal stool isolates were significantly more prevalent in hilly areas (p<0.05) than in plain areas. Polymerase chain reaction demonstrated the presence of stx1, stx2, hly, espP, saa, toxB, and iha genes in 117 (83.5%), 94 (67.1%), 77 (55%), 33 (23%), 62 (44.2%), 29 (20.7%), and 51 (36%) of the isolates, respectively. Five new serogroups (O55, O33, O173, O165, and O136) are being reported for the first time from India. Four isolates from serogroup O103 were found in mutton and stool specimens of cattle and humans (n=160). One isolate from serogroup O104 was isolated from a mutton sample. MLVA suggested the potential transmission of STEC from contaminated meat and bovine sources. This study confirms the frequent contamination of mutton samples (24%), whereas chicken and pork samples were negative for STEC. This study demonstrates the presence of STEC that carry a large repertoire of virulence genes and the potential transmission of STEC from contaminated mutton and animal stools in north India.
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Affiliation(s)
- Ajay Kumar
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research , Chandigarh, India
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Levine JA, Hansen AM, Michalski JM, Hazen TH, Rasko DA, Kaper JB. H-NST induces LEE expression and the formation of attaching and effacing lesions in enterohemorrhagic Escherichia coli. PLoS One 2014; 9:e86618. [PMID: 24466172 PMCID: PMC3897749 DOI: 10.1371/journal.pone.0086618] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/17/2013] [Indexed: 11/19/2022] Open
Abstract
Background Enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli are important causes of morbidity and mortality worldwide. These enteric pathogens contain a type III secretion system (T3SS) responsible for the attaching and effacing (A/E) lesion phenotype. The T3SS is encoded by the locus of enterocyte effacement (LEE) pathogenicity island. The H-NS-mediated repression of LEE expression is counteracted by Ler, the major activator of virulence gene expression in A/E pathogens. A regulator present in EPEC, H-NST, positively affects expression of H-NS regulon members in E. coli K-12, although the effect of H-NST on LEE expression and virulence of A/E pathogens has yet-to-be determined. Results We examine the effect of H-NST on LEE expression and A/E lesion formation on intestinal epithelial cells. We find that H-NST positively affects the levels of LEE-encoded proteins independently of ler and induces A/E lesion formation. We demonstrate H-NST binding to regulatory regions of LEE1 and LEE3, the first report of DNA-binding by H-NST. We characterize H-NST mutants substituted at conserved residues including Ala16 and residues Arg60 and Arg63, which are part of a potential DNA-binding domain. The single mutants A16V, A16L, R60Q and the double mutant R60Q/R63Q exhibit a decreased effect on LEE expression and A/E lesion formation. DNA mobility shift assays reveal that these residues are important for H-NST to bind regulatory LEE DNA targets. H-NST positively affects Ler binding to LEE DNA in the presence of H-NS, and thereby potentially helps Ler displace H-NS bound to DNA. Conclusions H-NST induces LEE expression and A/E lesion formation likely by counteracting H-NS-mediated repression. We demonstrate that H-NST binds to DNA and identify arginine residues that are functionally important for DNA-binding. Our study suggests that H-NST provides an additional means for A/E pathogens to alleviate repression of virulence gene expression by H-NS to promote virulence capabilities.
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Affiliation(s)
- Jonathan A. Levine
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Graduate Program in Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, United States of America
| | - Anne-Marie Hansen
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jane M. Michalski
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Tracy H. Hazen
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - David A. Rasko
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - James B. Kaper
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Lin CN, Sun WSW, Lu HY, Ng SC, Liao YS, Syu WJ. Protein interactions and regulation of EscA in enterohemorrhagic E. coli. PLoS One 2014; 9:e85354. [PMID: 24454847 PMCID: PMC3890302 DOI: 10.1371/journal.pone.0085354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/26/2013] [Indexed: 11/18/2022] Open
Abstract
Infections caused by enterohemorrhagic Escherichia coli (EHEC) can lead to diarrhea with abdominal cramps and sometimes are complicated by severe hemolytic uremic syndrome. EHEC secretes effector proteins into host cells through a type III secretion system that is composed of proteins encoded by a chromosomal island, locus for the enterocyte effacement (LEE). EspA is the major component of the filamentous structure connecting the bacteria and the host's cells. Synthesis and secretion of EspA must be carefully controlled since the protein is prone to polymerize. CesAB, CesA2, and EscL have been identified as being able to interact with EspA. Furthermore, the intracellular level of EspA declines when cesAB, cesA2, and escL are individually deleted. Here, we report a LEE gene named l0033, which also affects the intracellular level of EspA. We renamed l0033 as escA since its counterpart in enteropathogenic E. coli has been recently described. Similar to CesAB, EscL, and CesA2, EscA interacts with EspA and enhances the protein stability of EspA. However, EscA is also able to interact with inner membrane-associated EscL, CesA2, and EscN, but not with cytoplasmic CesAB. In terms of gene organizations, escA locates in LEE3. Expression of EscA is faithfully regulated via Mpc, the first gene product of LEE3. Since Mpc is tightly regulated to low level, we suggest that EscA is highly synchronized and critical to the process of escorting EspA to its final destination.
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Affiliation(s)
- Ching-Nan Lin
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Wei-Sheng W. Sun
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan, Republic of China
- Taiwan International Graduate Program in Molecular Medicine, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Hui-Yin Lu
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Swee-Chuan Ng
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Ying-Shu Liao
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Wan-Jr Syu
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
- Taiwan International Graduate Program in Molecular Medicine, Academia Sinica, Taipei, Taiwan, Republic of China
- * E-mail:
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Protection of mice against Shiga toxin 2 (Stx2)-associated damage by maternal immunization with a Brucella lumazine synthase-Stx2 B subunit chimera. Infect Immun 2014; 82:1491-9. [PMID: 24421050 DOI: 10.1128/iai.00027-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Hemolytic-uremic syndrome (HUS) is defined as the triad of anemia, thrombocytopenia, and acute kidney injury. Enterohemorrhagic Shiga toxin (Stx)-producing Escherichia coli (EHEC), which causes a prodromal hemorrhagic enteritis, remains the most common etiology of the typical or epidemic form of HUS. Because no licensed vaccine or effective therapy is presently available for human use, we recently developed a novel immunogen based on the B subunit of Shiga toxin 2 (Stx2B) and the enzyme lumazine synthase from Brucella spp. (BLS) (BLS-Stx2B). The aim of this study was to analyze maternal immunization with BLS-Stx2B as a possible approach for transferring anti-Stx2 protection to the offspring. BALB/c female mice were immunized with BLS-Stx2B before mating. Both dams and pups presented comparable titers of anti-Stx2B antibodies in sera and fecal extracts. Moreover, pups were totally protected against a lethal dose of systemic Stx2 injection up to 2 to 3 months postpartum. In addition, pups were resistant to an oral challenge with an Stx2-producing EHEC strain at weaning and did not develop any symptomatology associated with Stx2 toxicity. Fostering experiments demonstrated that anti-Stx2B neutralizing IgG antibodies were transmitted through breast-feeding. Pups that survived the EHEC infection due to maternally transferred immunity prolonged an active and specific immune response that protected them against a subsequent challenge with intravenous Stx2. Our study shows that maternal immunization with BLS-Stx2B was very effective at promoting the transfer of specific antibodies, and suggests that preexposure of adult females to this immunogen could protect their offspring during the early phase of life.
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Morgan JK, Vendura KW, Stevens SM, Riordan JT. RcsB determines the locus of enterocyte effacement (LEE) expression and adherence phenotype of Escherichia coli O157 : H7 spinach outbreak strain TW14359 and coordinates bicarbonate-dependent LEE activation with repression of motility. MICROBIOLOGY-SGM 2013; 159:2342-2353. [PMID: 23985143 DOI: 10.1099/mic.0.070201-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The 2006 US spinach outbreak of Escherichia coli O157 : H7, characterized by unusually severe disease, has been attributed to a strain (TW14359) with enhanced pathogenic potential, including elevated virulence gene expression, robust adherence and the presence of novel virulence factors. This study proposes a mechanism for the unique virulence expression and adherence phenotype of this strain, and further expands the role for regulator RcsB in control of the E. coli locus of enterocyte effacement (LEE) pathogenicity island. Proteomic analysis of TW14359 revealed a virulence proteome consistent with previous transcriptome studies that included elevated levels of the LEE regulatory protein Ler and type III secretion system (T3SS) proteins, secreted T3SS effectors and Shiga toxin 2. Basal levels of the LEE activator and Rcs phosphorelay response regulator, RcsB, were increased in strain TW14359 relative to O157 : H7 strain Sakai. Deletion of rcsB eliminated inherent differences between these strains in ler expression, and in T3SS-dependent adherence. A reciprocating regulatory pathway involving RcsB and LEE-encoded activator GrlA was identified and predicted to co-ordinate LEE activation with repression of the flhDC flagellar regulator and motility. Overexpression of grlA was shown to increase RcsB levels, but did not alter expression from promoters driving rcsB transcription. Expression of rcsDB and RcsB was determined to increase in response to physiological levels of bicarbonate, and bicarbonate-dependent stimulation of the LEE was shown to be dependent on an intact Rcs system and ler activator grvA. The results of this study significantly broaden the role for RcsB in enterohaemorrhagic E. coli virulence regulation.
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Affiliation(s)
- Jason K Morgan
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA
| | - Khoury W Vendura
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA
| | - Stanley M Stevens
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA
| | - James T Riordan
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA
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Discrimination of enterohemorrhagic Escherichia coli (EHEC) from non-EHEC strains based on detection of various combinations of type III effector genes. J Clin Microbiol 2013; 51:3257-62. [PMID: 23884997 DOI: 10.1128/jcm.01471-13] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) strains comprise a subgroup of Shiga-toxin (Stx)-producing E. coli (STEC) and are characterized by a few serotypes. Among these, seven priority STEC serotypes (O26:H11, O45:H2, O103:H2, O111:H8, O121:H19, O145:H28, and O157:H7) are most frequently implicated in severe clinical illness worldwide. Currently, standard methods using stx, eae, and O-serogroup-specific gene sequences for detecting the top 7 EHEC serotypes bear the disadvantage that these genes can be found in non-EHEC strains as well. Here, we explored the suitability of ureD, espV, espK, espN, Z2098, and espM1 genes and combinations thereof as candidates for a more targeted EHEC screening assay. For a very large panel of E. coli strains (n = 1,100), which comprised EHEC (n = 340), enteropathogenic E. coli (EPEC) (n = 392), STEC (n = 193), and apathogenic strains (n = 175), we showed that these genetic markers were more prevalent in EHEC (67.1% to 92.4%) than in EPEC (13.3% to 45.2%), STEC (0.5% to 3.6%), and apathogenic E. coli strains (0 to 2.9%). It is noteworthy that 38.5% of the EPEC strains that tested positive for at least one of these genetic markers belonged to the top 7 EHEC serotypes, suggesting that such isolates might be Stx-negative derivatives of EHEC. The associations of espK with either espV, ureD, or Z2098 were the best combinations for more specific and sensitive detection of the top 7 EHEC strains, allowing detection of 99.3% to 100% of these strains. In addition, detection of 93.7% of the EHEC strains belonging to other serotypes than the top 7 offers a possibility for identifying new emerging EHEC strains.
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Different Effects of Six Antibiotics and Ten Traditional Chinese Medicines on Shiga Toxin Expression by Escherichia coli O157:H7. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:121407. [PMID: 23956764 PMCID: PMC3730174 DOI: 10.1155/2013/121407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 06/17/2013] [Accepted: 06/22/2013] [Indexed: 11/17/2022]
Abstract
This study compared the effects of ten types of traditional Chinese medicines (TCMs) and six different antibiotics on E. coli O157:H7 Shiga toxin gene (stx2) mRNA expression level based on real-time PCR and the expression level of Stx toxin using an ELISA quantitative assay. We also compared their effects on the induction of the SOS response. The results clearly indicated that all ten TCMs had negative results in the SOS response induction test, while most TCMs did not increase the levels of stx2 mRNA and the Stx toxin. Some TCMs did increase the mRNA levels of the stx2 gene and the Stx toxin level, but their increases were much lower than those caused by antibiotics. With the exception of cefotaxime, the six antibiotics increased the Stx toxin level and increased the stx2 gene mRNA level. With the exceptions of cefotaxime and tetracycline, the antibiotics increased the SOS induction response. These results suggest that TCMs may have advantages compared with antibiotics, when treating E. coli O157:H7; TCMs did not greatly increase Stx toxin production and release.
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Thanabalasuriar A, Kim J, Gruenheid S. The inhibition of COPII trafficking is important for intestinal epithelial tight junction disruption during enteropathogenic Escherichia coli and Citrobacter rodentium infection. Microbes Infect 2013; 15:738-44. [PMID: 23747681 DOI: 10.1016/j.micinf.2013.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 04/04/2013] [Accepted: 05/13/2013] [Indexed: 11/24/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) are bacterial pathogens that cause severe illnesses in humans. Citrobacter rodentium is a related mouse pathogen that serves as a small animal model for EPEC and EHEC infections. EPEC, EHEC and C. rodentium translocate bacterial virulence proteins directly into host intestinal cells via a type III secretion system (T3SS). Non-LEE-encoded effector A (NleA) is a T3SS effector that is common to EPEC, EHEC and C. rodentium. NleA interacts with and inhibits the mammalian COPII complex, impairing cellular secretion; this interaction is required for bacterial virulence. Although diarrhea is a hallmark of EPEC, EHEC and C. rodentium infections, the underlying mechanisms are not well characterized. One of the essential functions of the intestine is to maintain a barrier between the lumen and submucosa. Tight junctions seal the space between adjacent epithelial cells creating this barrier. Consequently, it is thought that the disruption of intestinal epithelial tight junctions by EPEC, EHEC, and C. rodentium could result in a loss of barrier function. In this study, we demonstrate that NleA mediated COPII inhibition is required for EPEC- and C. rodentium-mediated disruption of tight junction proteins and increases in fecal water content.
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Affiliation(s)
- Ajitha Thanabalasuriar
- Department of Microbiology and Immunology, McGill University, 3649 Promenade Sir William Osler, Montreal, Quebec H3G 0B1, Canada
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Interactions between LPS moieties and macrophage pattern recognition receptors. Vet Immunol Immunopathol 2013; 152:28-36. [DOI: 10.1016/j.vetimm.2012.09.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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49
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Towards a molecular definition of enterohemorrhagic Escherichia coli (EHEC): detection of genes located on O island 57 as markers to distinguish EHEC from closely related enteropathogenic E. coli strains. J Clin Microbiol 2013; 51:1083-8. [PMID: 23325824 DOI: 10.1128/jcm.02864-12] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Among strains of Shiga-toxin (Stx) producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are associated with severe clinical illness in humans. These strains are also called enterohemorrhagic E. coli (EHEC), and the development of methods for their reliable detection from food has been challenging thus far. PCR detection of major EHEC virulence genes stx1, stx2, eae, and O-serogroup-specific genes is useful but does not identify EHEC strains specifically. Searching for the presence of additional genes issued from E. coli O157:H7 genomic islands OI-122 and OI-71 increases the specificity but does not clearly discriminate EHEC from enteropathogenic E. coli (EPEC) strains. Here, we identified two putative genes, called Z2098 and Z2099, from the genomic island OI-57 that were closely associated with EHEC and their stx-negative derivative strains (87% for Z2098 and 91% for Z2099). Z2098 and Z2099 were rarely found in EPEC (10% for Z2098 and 12% for Z2099), STEC (2 and 15%), and apathogenic E. coli (1% each) strains. Our findings indicate that Z2098 and Z2099 are useful genetic markers for a more targeted diagnosis of typical EHEC and new emerging EHEC strains.
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Hansen AM, Jin DJ. SspA up-regulates gene expression of the LEE pathogenicity island by decreasing H-NS levels in enterohemorrhagic Escherichia coli. BMC Microbiol 2012; 12:231. [PMID: 23051860 PMCID: PMC3539938 DOI: 10.1186/1471-2180-12-231] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 10/09/2012] [Indexed: 11/29/2022] Open
Abstract
Background Enterohemorrhagic Escherichia coli (EHEC) colonizes the intestinal epithelium and causes attaching and effacing (A/E) lesions. Expression of virulence genes, particularly those from the locus of the enterocyte effacement (LEE) pathogenicity island is required for the formation of a type three secretion system, which induces A/E lesion formation. Like other horizontally acquired genetic elements, expression of the LEE is negatively regulated by H-NS. In the non-pathogenic Escherichia coli K-12 strain the stringent starvation protein A (SspA) inhibits accumulation of H-NS, and thereby allows de-repression of the H-NS regulon during the stationary phase of growth. However, the effect of SspA on the expression of H-NS-controlled virulence genes in EHEC is unknown. Results Here we assess the effect of SspA on virulence gene expression in EHEC. We show that transcription of virulence genes including those of the LEE is decreased in an sspA mutant, rendering the mutant strain defective in forming A/E lesions. A surface exposed pocket of SspA is functionally important for the regulation of the LEE and for the A/E phenotype. Increased expression of ler alleviates LEE expression in an sspA mutant, suggesting that the level of Ler in the mutant is insufficient to counteract H-NS-mediated repression. We demonstrate that the H-NS level is two-fold higher in an sspA mutant compared to wild type, and that the defects of the sspA mutant are suppressed by an hns null mutation, indicating that hns is epistatic to sspA in regulating H-NS repressed virulence genes. Conclusions SspA positively regulates the expression of EHEC virulence factors by restricting the intracellular level of H-NS. Since SspA is conserved in many bacterial pathogens containing horizontally acquired pathogenicity islands controlled by H-NS, our study suggests a common mechanism whereby SspA potentially regulates the expression of virulence genes in these pathogens.
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Affiliation(s)
- Anne-Marie Hansen
- Transcription Control Section, Gene Regulation and Chromosome Biology Laboratory, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
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