Biochemistry, Genetics and Molecular Biology › Endocrinology

Pathogenesis and Virulence of Escherichia coli

Works Count: 42327

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This cluster of papers focuses on the pathogenesis and virulence mechanisms of Escherichia coli, particularly in the context of urinary tract infections, Shiga toxin production, bacterial invasion, and genomic analysis. It also covers topics related to vaccine development and molecular pathogenesis.

Keywords

Escherichia coli; pathogenicity; virulence; genomic analysis; Shiga toxin; bacterial invasion; urinary tract infection; molecular pathogenesis; type III secretion system; vaccine development

Vero response to a cytotoxin of Escherichia coli

1977-12-01

Jack Konowalchuk , Joan I. Speirs , S. Stavrić

A cytotoxin was found in culture filtrates of a number of Escherichia coli strains that differed from the known heat-stable and heat-labile enterotoxins of E. coli. It was cytotoxic for … A cytotoxin was found in culture filtrates of a number of Escherichia coli strains that differed from the known heat-stable and heat-labile enterotoxins of E. coli. It was cytotoxic for Vero but not for Y-1 or CHO cells, and its effect on Vero was distinctly different from that of heat-labile enterotoxin. It was labile to heat and antigenically different from heat-labile enterotoxin, and membrane filtration indicated a molecular weight of 10,000 to 30,000.

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Detection and Characterization of Shiga Toxigenic Escherichia coli by Using Multiplex PCR Assays for stx 1 , stx 2 , eaeA , Enterohemorrhagic E. coli hlyA , rfb O111 , and rfb O157

1998-02-01

Adrienne W. Paton , James C. Paton

ABSTRACT Shiga toxigenic Escherichia coli (STEC) comprises a diverse group of organisms capable of causing severe gastrointestinal disease in humans. Within the STEC family, certain strains appear to be of … ABSTRACT Shiga toxigenic Escherichia coli (STEC) comprises a diverse group of organisms capable of causing severe gastrointestinal disease in humans. Within the STEC family, certain strains appear to be of greater virulence for humans, for example, those belonging to serogroups O111 and O157 and those with particular combinations of other putative virulence traits. We have developed two multiplex PCR assays for the detection and genetic characterization of STEC in cultures of feces or foodstuffs. Assay 1 utilizes four PCR primer pairs and detects the presence of stx 1 , stx 2 (including variants of stx 2 ), eaeA , and enterohemorrhagic E. coli hlyA , generating amplification products of 180, 255, 384, and 534 bp, respectively. Assay 2 uses two primer pairs specific for portions of the rfb (O-antigen-encoding) regions of E. coli serotypes O157 and O111, generating PCR products of 259 and 406 bp, respectively. The two assays were validated by testing 52 previously characterized STEC strains and observing 100% agreement with previous results. Moreover, assay 2 did not give a false-positive O157 reaction with enteropathogenic E. coli strains belonging to clonally related serogroup O55. Assays 1 and 2 detected STEC of the appropriate genotype in primary fecal cultures from five patients with hemolytic-uremic syndrome and three with bloody diarrhea. Thirty-one other primary fecal cultures from patients without evidence of STEC infection were negative.

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Associations between Virulence Factors of Shiga Toxin-ProducingEscherichia coliand Disease in Humans

1999-03-01

Patrick Boerlin , Scott A. McEwen , Franziska Boerlin-Petzold +3 more

ABSTRACT Associations between known or putative virulence factors of Shiga toxin-producing Escherichia coli and disease in humans were investigated. Univariate analysis and multivariate logistic regression analysis of a set of … ABSTRACT Associations between known or putative virulence factors of Shiga toxin-producing Escherichia coli and disease in humans were investigated. Univariate analysis and multivariate logistic regression analysis of a set of 237 isolates from 118 serotypes showed significant associations between the presence of genes for intimin ( eae ) and Shiga toxin 2 ( stx 2 ) and isolates from serotypes reported in humans. Similar associations were found with isolates from serotypes reported in hemorrhagic colitis and hemolytic-uremic syndrome. The enterohemorrhagic E. coli (EHEC) hemolysin gene was significantly associated with isolates from serotypes found in severe diseases in univariate analysis but not in multivariate logistic regression models. A strong association between the intimin and EHEC-hemolysin genes may explain the lack of statistical significance of EHEC hemolysin in these multivariate models, but a true lack of biological significance of the hemolysin in humans or in disease cannot be excluded. This result warrants further investigations of this topic. Multivariate analysis revealed an interaction between the eae and stx 2 genes, thus supporting the hypothesis of the synergism between the adhesin intimin and Shiga toxin 2. A strong statistical association was observed between the stx 2 gene and severity of disease for a set of 112 human isolates from eight major serotypes. A comparison of 77 isolates of bovine origin and 91 human isolates belonging to six major serotypes showed significant associations of the genes for Shiga toxin 1 and EspP protease with bovine isolates and an increased adherence on HEp-2 cell cultures for human isolates, particularly from diarrheic patients and healthy persons.

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The Epidemiology of Infections Caused by Escherichia coli O157: H7, Other Enterohemorrhagic E. coli, and the Associated Hemolytic Uremic Syndrome

1991-01-01

Patricia M. Griffin , Robert V. Tauxe

Journal Article The Epidemiology of Infections Caused by Escherichia coli O157: H7, Other Enterohemorrhagic E. coli , and the Associated Hemolytic Uremic Syndrome Get access Patricia M. Griffin, Patricia M. … Journal Article The Epidemiology of Infections Caused by Escherichia coli O157: H7, Other Enterohemorrhagic E. coli , and the Associated Hemolytic Uremic Syndrome Get access Patricia M. Griffin, Patricia M. Griffin Enteric Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control, Public Health Service, U.S. Department of Health and Human ServicesAtlanta, GA Dr. Patricia M. Griffin, Centers for Disease Control, Enteric Diseases Branch, Mail stop C09, Atlanta, GA 30333 Search for other works by this author on: Oxford Academic PubMed Google Scholar Robert V. Tauxe Robert V. Tauxe Enteric Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control, Public Health Service, U.S. Department of Health and Human ServicesAtlanta, GA Search for other works by this author on: Oxford Academic PubMed Google Scholar Epidemiologic Reviews, Volume 13, Issue 1, 1991, Pages 60–98, https://doi.org/10.1093/oxfordjournals.epirev.a036079 Published: 01 March 1991 Article history Published: 01 March 1991 Received: 22 March 1991 Revision received: 26 June 1991

Construction of an eae deletion mutant of enteropathogenic Escherichia coli by using a positive-selection suicide vector

1991-12-01

Michael S. Donnenberg , James B. Kaper

The ability to attach to epithelial cells, efface the microvillus surface, and disrupt the underlying cytoskeleton is characteristic of enteropathogenic Escherichia coli (EPEC). Recently, eae, a gene necessary for this … The ability to attach to epithelial cells, efface the microvillus surface, and disrupt the underlying cytoskeleton is characteristic of enteropathogenic Escherichia coli (EPEC). Recently, eae, a gene necessary for this phenomenon, was described (A. E. Jerse, J. Yu, B. D. Tall, and J. B. Kaper, Proc. Natl. Acad. Sci. USA 87:7839-7843, 1990). We report the use of a novel suicide vector containing the pir-dependent R6K replicon and the sacB gene of Bacillus subtilis to construct an eae deletion mutant of EPEC. This system enables positive selection for the loss of vector sequences. The resulting mutant, CVD206, is indistinguishable from the wild-type strain except for the loss of a 94-kDa outer membrane protein and attaching and effacing ability. Both the 94-kDa outer membrane protein and attaching and effacing ability are restored upon reintroduction of the eae gene on a plasmid. These results confirm the role of the eae gene in the attaching and effacing activity of EPEC and establish the utility of a new system for the construction of deletion mutations.

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Bacterial Adhesion and Entry into Host Cells

2006-02-01

Javier Pizarro‐Cerdá , Pascale Cossart

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Pathogenic Escherichia coli

2004-02-01

James B. Kaper , James P. Nataro , Harry L. T. Mobley

Genomic islands in pathogenic and environmental microorganisms

2004-04-21

Ulrich Dobrindt , Bianca Hochhut , Ute Hentschel +1 more

Presence of adherent Escherichia coli strains in ileal mucosa of patients with Crohn's disease

1998-12-01

Arlette Darfeuille–Michaud , Christel Neut , Nicolas Barnich +7 more

The population genetics of commensal Escherichia coli

2010-02-16

Olivier Tenaillon , David Skurnik , Bertrand Picard +1 more

Escherichia coli that Cause Diarrhea: Enterotoxigenic, Enteropathogenic, Enteroinvasive, Enterohemorrhagic, and Enteroadherent

1987-03-01

Myron M. Levine

There are four major categories of diarrheagenic Escherichia coli: enterotoxigenic (a major cause of travelers' diarrhea and infant diarrhea in less-developed countries), enteroinvasive (a cause of dysentery), enteropathogenic (an important … There are four major categories of diarrheagenic Escherichia coli: enterotoxigenic (a major cause of travelers' diarrhea and infant diarrhea in less-developed countries), enteroinvasive (a cause of dysentery), enteropathogenic (an important cause of infant diarrhea), and enterohemorrhagic (a cause of hemorrhagic colitis and hemolytic uremic syndrome). Besides manifesting distinct clinical patterns, these categories of E. coli differ in their epidemiology and pathogenesis and in their O:H serotypes. Common features (albeit distinct for each category) include plasmid-encoded virulence properties, characteristic interactions with intestinal mucosa, and elaboration of various types of enterotoxins or cytotoxins. A less-well-defined fifth category of diarrheagenic E. coli is that of enteroadherent E. coli, so far identifiable only by their pattern of adherence to Hep-2 cells in tissue culture.

Virulence factors in Escherichia coli urinary tract infection

1991-01-01

James R. Johnson

Uropathogenic strains of Escherichia coli are characterized by the expression of distinctive bacterial properties, products, or structures referred to as virulence factors because they help the organism overcome host defenses … Uropathogenic strains of Escherichia coli are characterized by the expression of distinctive bacterial properties, products, or structures referred to as virulence factors because they help the organism overcome host defenses and colonize or invade the urinary tract. Virulence factors of recognized importance in the pathogenesis of urinary tract infection (UTI) include adhesins (P fimbriae, certain other mannose-resistant adhesins, and type 1 fimbriae), the aerobactin system, hemolysin, K capsule, and resistance to serum killing. This review summarizes the virtual explosion of information regarding the epidemiology, biochemistry, mechanisms of action, and genetic basis of these urovirulence factors that has occurred in the past decade and identifies areas in need of further study. Virulence factor expression is more common among certain genetically related groups of E. coli which constitute virulent clones within the larger E. coli population. In general, the more virulence factors a strain expresses, the more severe an infection it is able to cause. Certain virulence factors specifically favor the development of pyelonephritis, others favor cystitis, and others favor asymptomatic bacteriuria. The currently defined virulence factors clearly contribute to the virulence of wild-type strains but are usually insufficient in themselves to transform an avirulent organism into a pathogen, demonstrating that other as-yet-undefined virulence properties await discovery. Virulence factor testing is a useful epidemiological and research tool but as yet has no defined clinical role. Immunological and biochemical anti-virulence factor interventions are effective in animal models of UTI and hold promise for the prevention of UTI in humans.

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Molecular mechanisms of Escherichia coli pathogenicity

2009-12-07

Matthew A. Croxen , B. Brett Finlay

Shiga-like toxins are neutralized by tailored multivalent carbohydrate ligands

2000-02-01

Pavel I. Kitov , Joanna Sadowska , George L. Mulvey +5 more

Angiogenins: a new class of microbicidal proteins involved in innate immunity

2003-01-27

Lora V. Hooper , Thaddeus S. Stappenbeck , Chieu V. Hong +1 more

Escherichia coli acid resistance: tales of an amateur acidophile

2004-10-20

John W. Foster

Escherichia coli O157:H7

1998-10-01

Paul S. Mead , Patricia M. Griffin

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Induction and Evasion of Host Defenses by Type 1-Piliated Uropathogenic Escherichia coli

1998-11-20

Matthew A. Mulvey , Yolanda S. López-Boado , Carole L. Wilson +4 more

Virtually all uropathogenic strains of Escherichia coli encode filamentous surface adhesive organelles called type 1 pili. High-resolution electron microscopy of infected mouse bladders revealed that type 1 pilus tips interacted … Virtually all uropathogenic strains of Escherichia coli encode filamentous surface adhesive organelles called type 1 pili. High-resolution electron microscopy of infected mouse bladders revealed that type 1 pilus tips interacted directly with the lumenal surface of the bladder, which is embedded with hexagonal arrays of integral membrane glycoproteins known as uroplakins. Attached pili were shortened and facilitated intimate contact of the bacteria with the uroplakin-coated host cells. Bacterial attachment resulted in exfoliation of host bladder epithelial cells as part of an innate host defense system. Exfoliation occurred through a rapid apoptosis-like mechanism involving caspase activation and host DNA fragmentation. Bacteria resisted clearance in the face of host defenses within the bladder by invading into the epithelium.

Bacteria–host communication: The language of hormones

2003-07-07

Vanessa Sperandio , Alfredo G. Torres , Bruce B. Jarvis +2 more

The interbacterial communication system known as quorum sensing (QS) utilizes hormone-like compounds referred to as autoinducers to regulate bacterial gene expression. Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is the agent … The interbacterial communication system known as quorum sensing (QS) utilizes hormone-like compounds referred to as autoinducers to regulate bacterial gene expression. Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is the agent responsible for outbreaks of bloody diarrhea in several countries. We previously proposed that EHEC uses a QS regulatory system to “sense” that it is within the intestine and activate genes essential for intestinal colonization. The QS system used by EHEC is the LuxS/autoinducer 2 (AI-2) system extensively involved in interspecies communication. The autoinducer AI-2 is a furanosyl borate diester whose synthesis depends on the enzyme LuxS. Here we show that an EHEC luxS mutant, unable to produce the bacterial autoinducer, still responds to a eukaryotic cell signal to activate expression of its virulence genes. We have identified this signal as the hormone epinephrine and show that β- and α-adrenergic antagonists can block the bacterial response to this hormone. Furthermore, using purified and in vitro synthesized AI-2 we showed that AI-2 is not the autoinducer involved in the bacterial signaling. EHEC produces another, previously undescribed autoinducer (AI-3) whose synthesis depends on the presence of LuxS. These results imply a potential cross-communication between the luxS /AI-3 bacterial QS system and the epinephrine host signaling system. Given that eukaryotic cell-to-cell signaling typically occurs through hormones, and that bacterial cell-to-cell signaling occurs through QS, we speculate that QS might be a “language” by which bacteria and host cells communicate.

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Bifidobacteria can protect from enteropathogenic infection through production of acetate

2011-01-01

Shinji Fukuda , Hidehiro Toh , Koji Hase +7 more

Genome sequence of enterohaemorrhagic Escherichia coli O157:H7

2001-01-01

Nicole T. Perna , Guy Plunkett , Valerie Burland +7 more

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A genetic locus of enterocyte effacement conserved among diverse enterobacterial pathogens.

1995-02-28

T K McDaniel , Karen G. Jarvis , Michael S. Donnenberg +1 more

Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli O157:H7 are intestinal pathogens that profoundly damage the microvilli and subapical cytoskeleton of epithelial cells. Here we report finding in EPEC a … Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli O157:H7 are intestinal pathogens that profoundly damage the microvilli and subapical cytoskeleton of epithelial cells. Here we report finding in EPEC a 35-kbp locus containing several regions implicated in formation of these lesions. DNA probes throughout this locus hybridize to E. coli O157:H7 and other pathogens of three genera that cause similar lesions but do not hybridize to avirulent members of the same species. The EPEC locus and a different virulence locus of uropathogenic E. coli insert into the E. coli chromosome at the identical site and share highly similar sequences near the point of insertion.

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A genetic locus of enteropathogenic Escherichia coli necessary for the production of attaching and effacing lesions on tissue culture cells.

1990-10-01

Ann E. Jerse , Jiaao Yu , Ben D. Tall +1 more

The ability of enteropathogenic Escherichia coli (EPEC) to form attaching and effacing intestinal lesions is a major characteristic of EPEC pathogenesis. Using TnphoA mutagenesis we have identified a chromosomal gene … The ability of enteropathogenic Escherichia coli (EPEC) to form attaching and effacing intestinal lesions is a major characteristic of EPEC pathogenesis. Using TnphoA mutagenesis we have identified a chromosomal gene (eae, for E. coli attaching and effacing) that is necessary for this activity. A DNA probe derived from this gene hybridizes to 100% of E. coli of EPEC serogroups that demonstrate attaching and effacing activity on tissue culture cells as well as other pathogenic E. coli that produce attaching and effacing intestinal lesions, such as RDEC-1 (an EPEC of weanling rabbits) and enterohemorrhagic E. coli. The predicted amino acid sequence derived from the nucleotide sequence of eae shows significant homology to that of the invasin of Yersinia pseudotuberculosis.

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Correlation of enterohemorrhagic Escherichia coli O157 prevalence in feces, hides, and carcasses of beef cattle during processing

2000-03-21

Robert O. Elder , James E. Keen , Gregory R. Siragusa +3 more

A survey was performed to estimate the frequency of enterohemorrhagic Escherichia coli O157:H7 or O157:nonmotile (EHEC O157) in feces and on hides within groups of fed cattle from single sources … A survey was performed to estimate the frequency of enterohemorrhagic Escherichia coli O157:H7 or O157:nonmotile (EHEC O157) in feces and on hides within groups of fed cattle from single sources (lots) presented for slaughter at meat processing plants in the Midwestern United States, as well as frequency of carcass contamination during processing from cattle within the same lots. Of 29 lots sampled, 72% had at least one EHEC O157-positive fecal sample and 38% had positive hide samples. Overall, EHEC O157 prevalence in feces and on hides was 28% (91 of 327) and 11% (38 of 355), respectively. Carcass samples were taken at three points during processing: preevisceration, postevisceration before antimicrobial intervention, and postprocessing after carcasses entered the cooler. Of 30 lots sampled, 87% had at least one EHEC O157-positive preevisceration sample, 57% of lots were positive postevisceration, and 17% had positive postprocessing samples. Prevalence of EHEC O157 in the three postprocessing samples was 43% (148 of 341), 18% (59 of 332) and 2% (6 of 330), respectively. Reduction in carcass prevalence from preevisceration to postprocessing suggests that sanitary procedures were effective within the processing plants. Fecal and hide prevalence were significantly correlated with carcass contamination (P = 0.001), indicating a role for control of EHEC O157 in live cattle.

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Shigella flexneri induces apoptosis in infected macrophages

1992-07-01

Arturo Zychlinsky , M.C. Prévost , Philippe Sansonetti

Shiga-toxin-producing Escherichia coli and haemolytic uraemic syndrome

2005-03-01

Phillip I. Tarr , Carrie A. Gordon , Wayne L. Chandler

Bacterial Invasion: The Paradigms of Enteroinvasive Pathogens

2004-04-08

Pascale Cossart , Philippe Sansonetti

Invasive bacteria actively induce their own uptake by phagocytosis in normally nonphagocytic cells and then either establish a protected niche within which they survive and replicate, or disseminate from cell … Invasive bacteria actively induce their own uptake by phagocytosis in normally nonphagocytic cells and then either establish a protected niche within which they survive and replicate, or disseminate from cell to cell by means of an actin-based motility process. The mechanisms underlying bacterial entry, phagosome maturation, and dissemination reveal common strategies as well as unique tactics evolved by individual species to establish infection.

Pathogenesis and Diagnosis of Shiga Toxin-Producing Escherichia coli Infections

1998-07-01

James C. Paton , Adrienne W. Paton

SUMMARY Since their initial recognition 20 years ago, Shiga toxin-producing Escherichia coli (STEC) strains have emerged as an important cause of serious human gastrointestinal disease, which may result in life-threatening … SUMMARY Since their initial recognition 20 years ago, Shiga toxin-producing Escherichia coli (STEC) strains have emerged as an important cause of serious human gastrointestinal disease, which may result in life-threatening complications such as hemolytic-uremic syndrome. Food-borne outbreaks of STEC disease appear to be increasing and, when mass-produced and mass-distributed foods are concerned, can involve large numbers of people. Development of therapeutic and preventative strategies to combat STEC disease requires a thorough understanding of the mechanisms by which STEC organisms colonize the human intestinal tract and cause local and systemic pathological changes. While our knowledge remains incomplete, recent studies have improved our understanding of these processes, particularly the complex interaction between Shiga toxins and host cells, which is central to the pathogenesis of STEC disease. In addition, several putative accessory virulence factors have been identified and partly characterized. The capacity to limit the scale and severity of STEC disease is also dependent upon rapid and sensitive diagnostic procedures for analysis of human samples and suspect vehicles. The increased application of advanced molecular technologies in clinical laboratories has significantly improved our capacity to diagnose STEC infection early in the course of disease and to detect low levels of environmental contamination. This, in turn, has created a potential window of opportunity for future therapeutic intervention.

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Test for Escherichia coli Enterotoxin Using Infant Mice: Application in a Study of Diarrhea in Children in Honolulu

1972-04-01

Andrew G. Dean , Y.-C. Ching , Randall G. Williams +1 more

In a new test for detection of Escherichia coli enterotoxin, supernates of broth cultures were injected into the stomachs of infant mice and fluid accumulation in the intestine was measured … In a new test for detection of Escherichia coli enterotoxin, supernates of broth cultures were injected into the stomachs of infant mice and fluid accumulation in the intestine was measured after 4 hr by weighing. Results with known positive and negative strains were comparable to those obtained with the rabbit-loop test, and the mouse test was easier to perform. Cholera toxin, unlike E. coli enterotoxin, did not dilate infant mouse intestine significantly, even in high concentrations. Use of the infant-mouse test in a study of 37 children with diarrhea in Honolulu revealed no enterotoxin-producing coliform bacteria in the stools. This is in contrast to studies reported from India, where such strains were found in a large proportion of undifferentiated cases of acute diarrhea in adults. None of 15 stock strains of E. coli serotypes generally thought to be enteropathogenic produced significant amounts of enterotoxin as measured by the test in mice.

Type V Protein Secretion Pathway: the Autotransporter Story

2004-12-01

Ian R. Henderson , Fernando Navarro‐García , Mickaël Desvaux +2 more

Gram-negative bacteria possess an outer membrane layer which constrains uptake and secretion of solutes and polypeptides. To overcome this barrier, bacteria have developed several systems for protein secretion. The type … Gram-negative bacteria possess an outer membrane layer which constrains uptake and secretion of solutes and polypeptides. To overcome this barrier, bacteria have developed several systems for protein secretion. The type V secretion pathway encompasses the autotransporter proteins, the two-partner secretion system, and the recently described type Vc or AT-2 family of proteins. Since its discovery in the late 1980s, this family of secreted proteins has expanded continuously, due largely to the advent of the genomic age, to become the largest group of secreted proteins in gram-negative bacteria. Several of these proteins play essential roles in the pathogenesis of bacterial infections and have been characterized in detail, demonstrating a diverse array of function including the ability to condense host cell actin and to modulate apoptosis. However, most of the autotransporter proteins remain to be characterized. In light of new discoveries and controversies in this research field, this review considers the autotransporter secretion process in the context of the more general field of bacterial protein translocation and exoprotein function.

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DiarrheagenicEscherichia coli

1998-01-01

James P. Nataro , James B. Kaper

Escherichia coli is the predominant nonpathogenic facultative flora of the human intestine. Some E. coli strains, however, have developed the ability to cause disease of the gastrointestinal, urinary, or central … Escherichia coli is the predominant nonpathogenic facultative flora of the human intestine. Some E. coli strains, however, have developed the ability to cause disease of the gastrointestinal, urinary, or central nervous system in even the most robust human hosts. Diarrheagenic strains of E. coli can be divided into at least six different categories with corresponding distinct pathogenic schemes. Taken together, these organisms probably represent the most common cause of pediatric diarrhea worldwide. Several distinct clinical syndromes accompany infection with diarrheagenic E. coli categories, including traveler's diarrhea (enterotoxigenic E. coli), hemorrhagic colitis and hemolytic-uremic syndrome (enterohemorrhagic E. coli), persistent diarrhea (enteroaggregative E. coli), and watery diarrhea of infants (entero-pathogenic E. coli). This review discusses the current level of understanding of the pathogenesis of the diarrheagenic E. coli strains and describes how their pathogenic schemes underlie the clinical manifestations, diagnostic approach, and epidemiologic investigation of these important pathogens.

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Pathogenicity Islands and the Evolution of Microbes

2000-10-01

Jörg Hacker , James B. Kaper

Virulence factors of pathogenic bacteria (adhesins, toxins, invasins, protein secretion systems, iron uptake systems, and others) may be encoded by particular regions of the prokaryotic genome termed pathogenicity islands. Pathogenicity … Virulence factors of pathogenic bacteria (adhesins, toxins, invasins, protein secretion systems, iron uptake systems, and others) may be encoded by particular regions of the prokaryotic genome termed pathogenicity islands. Pathogenicity islands were first described in human pathogens of the species Escherichia coli, but have recently been found in the genomes of various pathogens of humans, animals, and plants. Pathogenicity islands comprise large genomic regions [10-200 kilobases (kb) in size] that are present on the genomes of pathogenic strains but absent from the genomes of nonpathogenic members of the same or related species. The finding that the G+C content of pathogenicity islands often differs from that of the rest of the genome, the presence of direct repeats at their ends, the association of pathogenicity islands with transfer RNA genes, the presence of integrase determinants and other mobility loci, and their genetic instability argue for the generation of pathogenicity islands by horizontal gene transfer, a process that is well known to contribute to microbial evolution. In this article we review these and other aspects of pathogenicity islands and discuss the concept that they represent a subclass of genomic islands. Genomic islands are present in the majority of genomes of pathogenic as well as nonpathogenic bacteria and may encode accessory functions which have been previously spread among bacterial populations.

Real-Time Whole-Genome Sequencing for Routine Typing, Surveillance, and Outbreak Detection of Verotoxigenic Escherichia coli

2014-02-27

Katrine Joensen , Flemming Scheutz , Ole Lund +4 more

Fast and accurate identification and typing of pathogens are essential for effective surveillance and outbreak detection. The current routine procedure is based on a variety of techniques, making the procedure … Fast and accurate identification and typing of pathogens are essential for effective surveillance and outbreak detection. The current routine procedure is based on a variety of techniques, making the procedure laborious, time-consuming, and expensive. With whole-genome sequencing (WGS) becoming cheaper, it has huge potential in both diagnostics and routine surveillance. The aim of this study was to perform a real-time evaluation of WGS for routine typing and surveillance of verocytotoxin-producing Escherichia coli (VTEC). In Denmark, the Statens Serum Institut (SSI) routinely receives all suspected VTEC isolates. During a 7-week period in the fall of 2012, all incoming isolates were concurrently subjected to WGS using IonTorrent PGM. Real-time bioinformatics analysis was performed using web-tools (www.genomicepidemiology.org) for species determination, multilocus sequence type (MLST) typing, and determination of phylogenetic relationship, and a specific VirulenceFinder for detection of E. coli virulence genes was developed as part of this study. In total, 46 suspected VTEC isolates were characterized in parallel during the study. VirulenceFinder proved successful in detecting virulence genes included in routine typing, explicitly verocytotoxin 1 (vtx1), verocytotoxin 2 (vtx2), and intimin (eae), and also detected additional virulence genes. VirulenceFinder is also a robust method for assigning verocytotoxin (vtx) subtypes. A real-time clustering of isolates in agreement with the epidemiology was established from WGS, enabling discrimination between sporadic and outbreak isolates. Overall, WGS typing produced results faster and at a lower cost than the current routine. Therefore, WGS typing is a superior alternative to conventional typing strategies. This approach may also be applied to typing and surveillance of other pathogens.

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Extended Virulence Genotypes ofEscherichia coliStrains from Patients with Urosepsis in Relation to Phylogeny and Host Compromise

2000-01-01

James R. Johnson , Adam L. Stell

Among 75 urosepsis isolates of Escherichia coli, 29 virulence factor (VF) genes were detected by use of a novel polymerase chain reaction (PCR) assay. Compared with probe hybridization, the PCR … Among 75 urosepsis isolates of Escherichia coli, 29 virulence factor (VF) genes were detected by use of a novel polymerase chain reaction (PCR) assay. Compared with probe hybridization, the PCR assay's specificity was 100% and sensitivity 97.1%. fyuA (yersiniabactin: overall prevalence, 93%), traT (serum resistance, 68%), and a pathogenicity-associated island marker (71%) occurred in most strains from both compromised and noncompromised hosts. Present in <20% of strains each were sfaS, focG (F1C fimbriae), afaldra, bmaE (M fimbriae), gafD (G fimbriae), cnf1, edtB (cytolethal distending toxin), cvaC (colicin V), and ibeA (invasion of brain endothelium). Different VFs were variously confined to virulence-associated phylogenetic group B2 (as defined by multilocus enzyme electrophoresis); concentrated in group B2, but with spread beyond; or concentrated outside of group B2. These findings provide novel insights into the VFs of extraintestinal pathogenic E. coli and demonstrate the new PCR assay's utility for molecular epidemiological studies.

Recent Advances in Understanding Enteric Pathogenic Escherichia coli

2013-10-01

Matthew A. Croxen , Robyn J. Law , Roland W. Scholz +3 more

Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli … Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.

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Enterotoxigenic Escherichia coli in Developing Countries: Epidemiology, Microbiology, Clinical Features, Treatment, and Prevention

2005-07-01

Firdausi Qadri , Ann–Mari Svennerholm , Shah M. Faruque +1 more

ETEC is an underrecognized but extremely important cause of diarrhea in the developing world where there is inadequate clean water and poor sanitation. It is the most frequent bacterial cause … ETEC is an underrecognized but extremely important cause of diarrhea in the developing world where there is inadequate clean water and poor sanitation. It is the most frequent bacterial cause of diarrhea in children and adults living in these areas and also the most common cause of traveler's diarrhea. ETEC diarrhea is most frequently seen in children, suggesting that a protective immune response occurs with age. The pathogenesis of ETEC-induced diarrhea is similar to that of cholera and includes the production of enterotoxins and colonization factors. The clinical symptoms of ETEC infection can range from mild diarrhea to a severe cholera-like syndrome. The effective treatment of ETEC diarrhea by rehydration is similar to treatment for cholera, but antibiotics are not used routinely for treatment except in traveler's diarrhea. The frequency and characterization of ETEC on a worldwide scale are inadequate because of the difficulty in recognizing the organisms; no simple diagnostic tests are presently available. Protection strategies, as for other enteric infections, include improvements in hygiene and development of effective vaccines. Increases in antimicrobial resistance will dictate the drugs used for the treatment of traveler's diarrhea. Efforts need to be made to improve our understanding of the worldwide importance of ETEC.

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Organised Genome Dynamics in the Escherichia coli Species Results in Highly Diverse Adaptive Paths

2009-01-22

Marie Touchon , Claire Hoede , Olivier Tenaillon +7 more

The Escherichia coli species represents one of the best-studied model organisms, but also encompasses a variety of commensal and pathogenic strains that diversify by high rates of genetic change. We … The Escherichia coli species represents one of the best-studied model organisms, but also encompasses a variety of commensal and pathogenic strains that diversify by high rates of genetic change. We uniformly (re-) annotated the genomes of 20 commensal and pathogenic E. coli strains and one strain of E. fergusonii (the closest E. coli related species), including seven that we sequenced to completion. Within the approximately 18,000 families of orthologous genes, we found approximately 2,000 common to all strains. Although recombination rates are much higher than mutation rates, we show, both theoretically and using phylogenetic inference, that this does not obscure the phylogenetic signal, which places the B2 phylogenetic group and one group D strain at the basal position. Based on this phylogeny, we inferred past evolutionary events of gain and loss of genes, identifying functional classes under opposite selection pressures. We found an important adaptive role for metabolism diversification within group B2 and Shigella strains, but identified few or no extraintestinal virulence-specific genes, which could render difficult the development of a vaccine against extraintestinal infections. Genome flux in E. coli is confined to a small number of conserved positions in the chromosome, which most often are not associated with integrases or tRNA genes. Core genes flanking some of these regions show higher rates of recombination, suggesting that a gene, once acquired by a strain, spreads within the species by homologous recombination at the flanking genes. Finally, the genome's long-scale structure of recombination indicates lower recombination rates, but not higher mutation rates, at the terminus of replication. The ensuing effect of background selection and biased gene conversion may thus explain why this region is A+T-rich and shows high sequence divergence but low sequence polymorphism. Overall, despite a very high gene flow, genes co-exist in an organised genome.

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Epidemiology ofEscherichia coliO157:H7 Outbreaks, United States, 1982–2002

2005-04-01

Josefa M. Rangel , P.H. Sparling , Collen Crowe +2 more

Escherichia coli O157:H7 causes 73,000 illnesses in the United States annually. We reviewed E. coli O157 outbreaks reported to Centers for Disease Control and Prevention (CDC) to better understand the … Escherichia coli O157:H7 causes 73,000 illnesses in the United States annually. We reviewed E. coli O157 outbreaks reported to Centers for Disease Control and Prevention (CDC) to better understand the epidemiology of E. coli O157. E. coli O157 outbreaks (>or=2 cases of E. coli O157 infection with a common epidemiologic exposure) reported to CDC from 1982 to 2002 were reviewed. In that period, 49 states reported 350 outbreaks, representing 8,598 cases, 1,493 (17%) hospitalizations, 354 (4%) hemolytic uremic syndrome cases, and 40 (0.5%) deaths. Transmission route for 183 (52%) was foodborne, 74 (21%) unknown, 50 (14%) person-to-person, 31 (9%) waterborne, 11 (3%) animal contact, and 1 (0.3%) laboratory-related. The food vehicle for 75 (41%) foodborne outbreaks was ground beef, and for 38 (21%) outbreaks, produce.

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Common themes in microbial pathogenicity revisited

1997-06-01

B. Brett Finlay , Stanley Falkow

Bacterial pathogens employ a number of genetic strategies to cause infection and, occasionally, disease in their hosts. Many of these virulence factors and their regulatory elements can be divided into … Bacterial pathogens employ a number of genetic strategies to cause infection and, occasionally, disease in their hosts. Many of these virulence factors and their regulatory elements can be divided into a smaller number of groups based on the conservation of similar mechanisms. These common themes are found throughout bacterial virulence factors. For example, there are only a few general types of toxins, despite a large number of host targets. Similarly, there are only a few conserved ways to build the bacterial pilus and nonpilus adhesins used by pathogens to adhere to host substrates. Bacterial entry into host cells (invasion) is a complex mechanism. However, several common invasion themes exist in diverse microorganisms. Similarly, once inside a host cell, pathogens have a limited number of ways to ensure their survival, whether remaining within a host vacuole or by escaping into the cytoplasm. Avoidance of the host immune defenses is key to the success of a pathogen. Several common themes again are employed, including antigenic variation, camouflage by binding host molecules, and enzymatic degradation of host immune components. Most virulence factors are found on the bacterial surface or secreted into their immediate environment, yet virulence factors operate through a relatively small number of microbial secretion systems. The expression of bacterial pathogenicity is dependent upon complex regulatory circuits. However, pathogens use only a small number of biochemical families to express distinct functional factors at the appropriate time that causes infection. Finally, virulence factors maintained on mobile genetic elements and pathogenicity islands ensure that new strains of pathogens evolve constantly. Comprehension of these common themes in microbial pathogenicity is critical to the understanding and study of bacterial virulence mechanisms and to the development of new "anti-virulence" agents, which are so desperately needed to replace antibiotics.

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Extensive mosaic structure revealed by the complete genome sequence of uropathogenic Escherichia coli

2002-12-05

Rodney A. Welch , Valerie Burland , Guy Plunkett +7 more

We present the complete genome sequence of uropathogenic Escherichia coli , strain CFT073. A three-way genome comparison of the CFT073, enterohemorrhagic E. coli EDL933, and laboratory strain MG1655 reveals that, … We present the complete genome sequence of uropathogenic Escherichia coli , strain CFT073. A three-way genome comparison of the CFT073, enterohemorrhagic E. coli EDL933, and laboratory strain MG1655 reveals that, amazingly, only 39.2% of their combined (nonredundant) set of proteins actually are common to all three strains. The pathogen genomes are as different from each other as each pathogen is from the benign strain. The difference in disease potential between O157:H7 and CFT073 is reflected in the absence of genes for type III secretion system or phage- and plasmid-encoded toxins found in some classes of diarrheagenic E. coli . The CFT073 genome is particularly rich in genes that encode potential fimbrial adhesins, autotransporters, iron-sequestration systems, and phase-switch recombinases. Striking differences exist between the large pathogenicity islands of CFT073 and two other well-studied uropathogenic E. coli strains, J96 and 536. Comparisons indicate that extraintestinal pathogenic E. coli arose independently from multiple clonal lineages. The different E. coli pathotypes have maintained a remarkable synteny of common, vertically evolved genes, whereas many islands interrupting this common backbone have been acquired by different horizontal transfer events in each strain.

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Infection by verocytotoxin-producing Escherichia coli

1989-01-01

Mohamed A. Karmali

Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a newly recognized group of enteric pathogens which are increasingly being recognized as common causes of diarrhea in some geographic settings. Outbreak studies indicate … Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a newly recognized group of enteric pathogens which are increasingly being recognized as common causes of diarrhea in some geographic settings. Outbreak studies indicate that most patients with VTEC infection develop mild uncomplicated diarrhea. However, a significant risk of two serious and potentially life-threatening complications, hemorrhagic colitis and the hemolytic uremic syndrome, makes VTEC infection a public health problem of serious concern. The main reservoirs of VTEC appear to be the intestinal tracts of animals, and foods of animal (especially bovine) origin are probably the principal sources for human infection. The term VT refers to a family of subunit exotoxins with high biological activity. Individual VTEC strains elaborate one or both of at least two serologically distinct, bacteriophage-mediated VTs (VT1 and VT2) which are closely related to Shiga toxin and are thus also referred to as Shiga-like toxins. The holotoxins bind to cells, via their B subunits, to a specific receptor which is probably the glycolipid, globotriosyl ceramide (Gb3). Binding is followed by internalization of the A subunit, which, after it is proteolytically nicked and reduced to the A1 fragment, inhibits protein synthesis in mammalian cells by inactivating 60S ribosomal subunits through selective structural modification of 28S ribosomal ribonucleic acid. The mechanism of VTEC diarrhea is still controversial, and the relative roles of locally acting VT and "attaching and effacing adherence" of VTEC to the mucosa have yet to be resolved. There is increasing evidence that hemolytic uremic syndrome and possibly hemorrhagic colitis result from the systemic action of VT on vascular endothelial cells. The role of antitoxic immunity in preventing the systemic complications of VTEC infection is being explored. Antibiotics appear to be contraindicated in the treatment of VTEC infection. The most common VTEC serotype associated with human disease is O157:H7, but over 50 different VT-positive O:H serotypes have now been identified. The best strategies for diagnosing human VTEC infection include testing for the presence of free VT in fecal filtrates and examining fecal cultures for VTEC by means of deoxyribonucleic acid probes that specify genes encoding VT1 and VT2. Both methods are currently confined to specialized laboratories and await commercial development for wider use. In the meantime, most laboratories should continue to screen for the most common human VTEC serotype, O157:H7, using a sorbitol-containing MacConkey medium.

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Enteropathogenic E. coli (EPEC) Transfers Its Receptor for Intimate Adherence into Mammalian Cells

1997-11-01

Brendan Kenny , Rebekah DeVinney , Markus Stein +3 more

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Sex and virulence in Escherichia coli: an evolutionary perspective

2006-05-04

Thierry Wirth , Daniel Falush , Ruiting Lan +7 more

Pathogenic Escherichia coli cause over 160 million cases of dysentery and one million deaths per year, whereas non-pathogenic E. coli constitute part of the normal intestinal flora of healthy mammals … Pathogenic Escherichia coli cause over 160 million cases of dysentery and one million deaths per year, whereas non-pathogenic E. coli constitute part of the normal intestinal flora of healthy mammals and birds. The evolutionary pathways underlying this dichotomy in bacterial lifestyle were investigated by multilocus sequence typing of a global collection of isolates. Specific pathogen types [enterohaemorrhagic E. coli, enteropathogenic E. coli, enteroinvasive E. coli, K1 and Shigella] have arisen independently and repeatedly in several lineages, whereas other lineages contain only few pathogens. Rates of evolution have accelerated in pathogenic lineages, culminating in highly virulent organisms whose genomic contents are altered frequently by increased rates of homologous recombination; thus, the evolution of virulence is linked to bacterial sex. This long-term pattern of evolution was observed in genes distributed throughout the genome, and thereby is the likely result of episodic selection for strains that can escape the host immune response.

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Actin accumulation at sites of bacterial adhesion to tissue culture cells: basis of a new diagnostic test for enteropathogenic and enterohemorrhagic Escherichia coli

1989-04-01

Stuart Knutton , Thomas J. Baldwin , P. H. Williams +1 more

Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) adhere to the intestinal mucosa and produce an attaching and effacing (AE) lesion in the brush border microvillous membrane; the AE … Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) adhere to the intestinal mucosa and produce an attaching and effacing (AE) lesion in the brush border microvillous membrane; the AE lesion is characterized by localized destruction of microvilli and intimate attachment of bacteria to the apical enterocyte membrane. A similar lesion is seen when bacteria adhere in vitro to a variety of human tissue culture cell lines. In both cases, dense concentrations of microfilaments are present in the apical cytoplasm beneath attached bacteria. Using a fluorescein-labeled phallotoxin, we have shown that these microfilaments are composed of actin. Cells infected with EPEC and EHEC strains known from electron microscopic studies to produce the AE lesion all exhibited intense spots of fluorescence which corresponded in size and position with each adherent bacterium; cells infected with adherent E. coli strains known not to produce the AE lesion did not produce this striking pattern of fluorescence and were indistinguishable from uninfected control cells. These results indicate that such site-specific concentrations of cytoskeletal actin are characteristic of the AE membrane lesion and can form the basis of a simple, highly sensitive diagnostic test for EPEC and EHEC.

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Revisiting the STEC Testing Approach: Using espK and espV to Make Enterohemorrhagic Escherichia coli (EHEC) Detection More Reliable in Beef

2016-01-22

Sabine Delannoy , Byron D. Chaves , Sarah A. Ison +5 more

Current methods for screening Enterohemorrhagic Escherichia coli (EHEC) O157 and non-O157 in beef enrichments typically rely on the molecular detection of stx, eae, and serogroup-specific wzx or wzy gene fragments. … Current methods for screening Enterohemorrhagic Escherichia coli (EHEC) O157 and non-O157 in beef enrichments typically rely on the molecular detection of stx, eae, and serogroup-specific wzx or wzy gene fragments. As these genetic markers can also be found in some non-EHEC strains, a number of 'false positive' results are obtained. Here, we explore the suitability of five novel molecular markers, espK, espV, ureD, Z2098, and CRISPRO26:H11 as candidates for a more accurate screening of EHEC strains of greater clinical significance in industrialized countries. Of the 1,739 beef enrichments tested, 180 were positive for both stx and eae genes. Ninety (50%) of these tested negative for espK, espV, ureD, and Z2098, but twelve out of these negative samples were positive for the CRISPRO26:H11 gene marker specific for a newly emerging virulent EHEC O26:H11 French clone. We show that screening for stx, eae, espK, and espV, in association with the CRISPRO26:H11 marker is a better approach to narrow down the EHEC screening step in beef enrichments. The number of potentially positive samples was reduced by 48.88% by means of this alternative strategy compared to the European and American reference methods, thus substantially improving the discriminatory power of EHEC screening systems. This approach is in line with the EFSA (European Food Safety Authority) opinion on pathogenic STEC published in 2013.

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Hemorrhagic Colitis Associated with a RareEscherichia coliSerotype

1983-03-24

Lee W. Riley , Robert S. Remis , Steven D. Helgerson +7 more

We investigated two outbreaks of an unusual gastrointestinal illness that affected at least 47 people in Oregon and Michigan in February through March and May through June 1982. The illness … We investigated two outbreaks of an unusual gastrointestinal illness that affected at least 47 people in Oregon and Michigan in February through March and May through June 1982. The illness was characterized by severe crampy abdominal pain, initially watery diarrhea followed by grossly bloody diarrhea, and little or no fever. It was associated with eating at restaurants belonging to the same fast-food restaurant chain in Oregon (P less than 0.005) and Michigan (P = 0.0005) and with eating any of three sandwiches containing three ingredients in common (beef patty, rehydrated onions, and pickles). Stool cultures did not yield previously recognized pathogens. However, a rare Escherichia coli serotype, O157:H7, that was not invasive or toxigenic by standard tests was isolated from 9 of 12 stools collected within four days of onset of illness in both outbreaks combined, and from a beef patty from a suspected lot of meat in Michigan. The only known previous isolation of this serotype was from a sporadic case of hemorrhagic colitis in 1975. This report describes a clinically distinctive gastrointestinal illness associated with E. coli O157:H7, apparently transmitted by undercooked meat.

The Risk of the Hemolytic–Uremic Syndrome after Antibiotic Treatment ofEscherichia coliO157:H7 Infections

2000-06-29

Craig S. Wong , Srdjan Jelačić , Rebecca L. Habeeb +2 more

Children with gastrointestinal infections caused by Escherichia coli O157:H7 are at risk for the hemolytic–uremic syndrome. Whether antibiotics alter this risk is unknown. Children with gastrointestinal infections caused by Escherichia coli O157:H7 are at risk for the hemolytic–uremic syndrome. Whether antibiotics alter this risk is unknown.

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Epidemic Profile of Shiga-Toxin–ProducingEscherichia coliO104:H4 Outbreak in Germany

2011-06-22

Christina Frank , Dirk Werber , Jakob P. Cramer +7 more

We describe an outbreak of gastroenteritis and the hemolytic-uremic syndrome caused by Shiga-toxin-producing Escherichia coli in Germany in May, June, and July, 2011. The consumption of sprouts was identified as … We describe an outbreak of gastroenteritis and the hemolytic-uremic syndrome caused by Shiga-toxin-producing Escherichia coli in Germany in May, June, and July, 2011. The consumption of sprouts was identified as the most likely vehicle of infection.We analyzed data from reports in Germany of Shiga-toxin-producing E. coli gastroenteritis and the hemolytic-uremic syndrome and clinical information on patients presenting to Hamburg University Medical Center (HUMC). An outbreak case was defined as a reported case of the hemolytic-uremic syndrome or of gastroenteritis in a patient infected by Shiga-toxin-producing E. coli, serogroup O104 or serogroup unknown, with an onset of disease during the period from May 1 through July 4, 2011, in Germany.A total of 3816 cases (including 54 deaths) were reported in Germany, 845 of which (22%) involved the hemolytic-uremic syndrome. The outbreak was centered in northern Germany and peaked around May 21 to 22. Most of the patients in whom the hemolytic-uremic syndrome developed were adults (88%; median age, 42 years), and women were overrepresented (68%). The estimated median incubation period was 8 days, with a median of 5 days from the onset of diarrhea to the development of the hemolytic-uremic syndrome. Among 59 patients prospectively followed at HUMC, the hemolytic-uremic syndrome developed in 12 (20%), with no significant differences according to sex or reported initial symptoms and signs. The outbreak strain was typed as an enteroaggregative Shiga-toxin-producing E. coli O104:H4, producing extended-spectrum beta-lactamase.In this outbreak, caused by an unusual E. coli strain, cases of the hemolytic-uremic syndrome occurred predominantly in adults, with a preponderance of cases occurring in women. The hemolytic-uremic syndrome developed in more than 20% of the identified cases.

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Diarrheagenic Escherichia coli

2016-11-05

Tânia A. T. Gomes , Waldir P. Elias , Isabel C. A. Scaletsky +5 more

Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in … Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.

Control of diarrhea and intestinal damage caused by enteropathogenic Escherichia coli using infant formula fermented with Lacticaseibacillus paracasei BMK2005: in vitro and in vivo evidences

2025-06-25

Kamel Bendjeddou , Amel Ait Meddour , Ahmed Adjebli +3 more | World Journal of Microbiology and Biotechnology

Structure of lymphostatin, a large multi-functional virulence factor of pathogenic Escherichia coli

2025-06-25

Matthias Grießmann , Tim Rasmussen , Vanessa J. Flegler +7 more | Nature Communications

Epidemiologic and Genomic Investigation of Sexually Transmitted Shigella sonnei, England

2025-06-24

Hannah Charles , David R. Greig , Craig Swift +6 more | Emerging infectious diseases

Shigellosis is a bacterial infection that causes enteric illness and can be sexually transmitted, particularly among gay, bisexual, and other men who have sex with men. Multiple extensively drug-resistant Shigella … Shigellosis is a bacterial infection that causes enteric illness and can be sexually transmitted, particularly among gay, bisexual, and other men who have sex with men. Multiple extensively drug-resistant Shigella strains have been detected through genomic surveillance and are associated with plasmids carrying the gene variant blaCTX-M-27 in the United Kingdom. We report an increase in possible sexually transmitted cases of Shigella bacteria carrying the blaCTX-M-15 gene variant, which was previously associated with travel. In 2023, there were 117 cases belonging to the 10 single-nucleotide polymorphism linkage cluster t10.1814. Although this cluster has been documented in England since August 2019, genetic analyses revealed that the blaCTX-M-15 gene variant entered the lineage on a novel resistance plasmid coinciding with the first outbreak case. Our analysis highlights the shifting antimicrobial resistance landscape of sexually transmitted Shigella bacteria. Parallel emergence of resistance determinants against third-generation cephalosporins in sexual transmission networks suggests high levels of antimicrobial selection pressure.

Inhibiting Multidrug Resistant Shigella flexneri using Comparative Genomics Guided In vitro and In Silico Screening

2025-06-23

Sarmishta Mukhopadhyay , Fernando Berton Zanchi , Gaurab Aditya Dhar +2 more | Journal of Ethnopharmacology

Isolation, Pathotyping and Drug Susceptibility Pattern of Escherichia coli Isolates from Diarrheic Piglets

2025-06-21

Das Adwitiya , Dilip Kumar Sarma , Rajeev Kumar Sharma +5 more | Indian Journal of Animal Research

Background: Multidrug resistant strains of Escherichia coli have been causing worldwide outbreaks of food borne diseases in recent years. The emergence of antibiotic-resistant strains of E. coli and the occurrence … Background: Multidrug resistant strains of Escherichia coli have been causing worldwide outbreaks of food borne diseases in recent years. The emergence of antibiotic-resistant strains of E. coli and the occurrence of transmissible drug resistance among the organism has amplified the complications associated with its control and treatment measures. Data associated with the prevalence, virulence factors and antimicrobial susceptibility of E. coli isolates are needed to be studied in order to develop an effective control strategy for colibacillosis in piggeries. The goal of the investigation was to study the antimicrobial susceptibility pattern and pathotyping of E. coli isolates from diarrhoeic piglets. Methods: 102 rectal swab samples were collected from diarrhoeic piglets of ICAR-AICRP/MSP on Pig, College of Veterinary Science, Assam Agricultural University, Khanapara, ICAR-National Research Centre on Pig, Rani, Guwahati, Assam and from different unorganized farms of the state. These samples were then inoculated in Luria Bertani (LB) broth and incubated aerobically at 37oC for 24 hours followed by sub culturing them in MacConkey’s lactose agar (MLA) and Eosin Methylene Blue (EMB) agar for purification of the suspected E. coli isolates. The isolates were characterized by biochemical tests and motility tests and were pathotyped based on detection of specific virulence genes by multiplex Polymerase Chain Reaction (PCR). Result: Out of 102 rectal swab samples examined, 92 (90.2%) yielded E. coli which included 41 (91.12%) of 45 samples collected from ICAR-AICRP/MSP on Pig, College of Veterinary Science, Assam Agricultural University, Khanapara and 32 (88.89%) of 36 samples from ICAR-National Research Centre on Pig, Rani, Guwahati, Assam and 19 (90.48%) of 21 samples from different unorganized farms. All the 92 E. coli isolates were examined for the presence of stx1, est1, elt1 and eaeA genes using specific primers. Among these isolates, 25 (27.17%) were positive for stx1 gene, 18(19.56%) for est1 gene, 6(6.52%) for elt1 gene, 3 (3.26%) for both genes est1 and elt1 and 12 (13.04%) for eaeA gene. Antimicrobial susceptibility pattern of the isolates revealed that the highest percentage (71.74%) of the isolates were resistant to tetracycline and the least (4.34%) to imipenem.

Phenotypic and genotypic characterization of biofilm-producing avian pathogenic Escherichia coli (APEC) isolates from Algerian poultry: associations between antimicrobial resistance and virulence genes

2025-06-21

Sarah Saci , Karim Houalı , Rossana Schena +6 more | Veterinary Research Communications

Modulation of cytokine expression by E. coli Nissle 1917 and its OMV in intestinal epithelial cell line HT-29

2025-06-21

Seyed Amir Hossein Hamidzadeh , Asal Katebi , Leila Hatami-Giklou Jajan +3 more | Immunobiology

Inflammatory bowel disease (IBD) is a chronic disease recognized as an autoimmune disorder. The purpose of this is to determine the impact of the E. coli strain Nissle 1917 (EcN) … Inflammatory bowel disease (IBD) is a chronic disease recognized as an autoimmune disorder. The purpose of this is to determine the impact of the E. coli strain Nissle 1917 (EcN) and its outer membrane vesicles (OMVs) on cytokine gene expression in an IBD cell line model (HT29) in the hope that these effects will guide the development of interventional therapeutic strategies for IBD. First, the cell viability of HT-29 cells treated with EcN and OMVs was evaluated using the MTT assay. Then, inflamed HT29 cells were inoculated with EcN bacteria (multiplicity of infection (MOI) 10, 100), and extracted OMVs (10, 50 μg/ml). Subsequently, cells were harvested for RNA extraction; followed by expression analysis using real-time PCR and also the evaluation of cytokines by ELISA assay. TNF-α, IL-12, and IL-1β mRNA expression was decreased in EcN bacteria (MOI 10 and 100) and OMV 10 μg/ml group. IL-6 mRNA increased in the MOI 100 of ECN group but decreased in OMV μg/ml, despite elevated IL-6 protein levels in the OMV 50 μg/ml. Notably, no detectable secretion of IL-12, TNF-α, or IL-1β was observed in ELISA assays, suggesting post-transcriptional regulation or low sensitivity. The findings revealed that EcN (MOI 10 and 100) enhanced anti-inflammatory IL-10 production, whereas OMV 10 μg/ml showed superior suppression on mRNA level compared to OMV 50 μg/ml.

Diarrheagenic Escherichia coli in children under five in the Americas: Prevalence, pathotype distribution, and socioenvironmental drivers

2025-06-20

Diego Fernando López Muñoz , Beatriz Giraldo Ospina , Cristian Alexander Vega Mosquera +3 more | medRxiv (Cold Spring Harbor Laboratory)

Abstract Aim To characterize the prevalence, pathotype distribution, and socioenvironmental drivers of diarrheagenic Escherichia coli (DEC) in children under five in the Americas. Methods A systematic review and meta-analysis of … Abstract Aim To characterize the prevalence, pathotype distribution, and socioenvironmental drivers of diarrheagenic Escherichia coli (DEC) in children under five in the Americas. Methods A systematic review and meta-analysis of studies (2015-2024) from PubMed, Scopus, Springer, SciELO, LILACS and Web of Science were conducted. Eligible studies reported DEC prevalence in children ≤ 5 years with acute diarrhea using molecular/microbiological diagnostics. Results Thirteen studies (7,485 participants) were included. Pooled DEC prevalence was 28.3% (95% CI: 21.6-35.7). PCR detected 1.4-fold higher prevalence than culture. Regional disparities included EPEC dominance in the Andean highlands (50.0%) and EAEC/EHEC co-occurrence in Amazonia (EAEC 8x post-hurricane). Limited water access (aOR 3.2) and poor sanitation were key risk factors; a 10% increase in water access reduced EPEC burden by 17%. Conclusion DEC poses a significant health burden in the Americas, with pathotype distribution linked to socioeconomic inequities. Molecular diagnostics are crucial for surveillance, and policy should prioritize WASH infrastructure and equitable diagnostics access to mitigate morbidity, antimicrobial resistance, and climate-amplified outbreaks. Summary Regional variations in the prevalence of diarrhoeagenic Escherichia coli and associated risk factors in children under five in the Americas were poorly understood, necessitating a systematic review. The study found a prevalence of 28.3%, with regional disparities and socioeconomic factors such as limited access to water driving infections. Improved water, sanitation and hygiene infrastructure, as well as molecular diagnostics, are critical for reducing paediatric diarrhoeal morbidity and antimicrobial resistance.

Exploring the Epidemiology and Genetic Complexity of Escherichia coli in Vertically Integrated Pig Production Systems Using Whole Genome Sequencing

2025-06-18

Anna Vilaró , L. Serra , Emma Solé +5 more | Veterinary Microbiology

Escherichia coli is a major pathogen responsible for enteric diseases in swine. This study aims to assess the genetic diversity, virulence factors, and antimicrobial resistance genes of E. coli isolated … Escherichia coli is a major pathogen responsible for enteric diseases in swine. This study aims to assess the genetic diversity, virulence factors, and antimicrobial resistance genes of E. coli isolated from diarrheic pigs within Spanish integrated production systems. Metadata, including epidemiological data and minimum inhibitory concentration (MIC), was collected for 350 clinical isolates reported to the laboratory between 2018 and 2022. MIC analysis using Ward's hierarchical clustering identified 17 phenotypic resistance clusters. A subset of 206 isolates, representing different production pyramids and phenotypic clusters, was selected for whole genome sequencing (WGS). In silico serotyping and multilocus sequence typing revealed high genetic diversity, with predominant serotypes O138:H14, O147:H14, O141:H4, and O108:H39, and sequence types ST10 and ST42. Only three ST131 isolates were found in a single production pyramid suggesting that swine associated ST131 is not contributing significantly to the epidemiology of human infections associated to this ST. Isolates were classified into six phylogroups, with phylogroup A being the most represented. AMR profiling identified a high percentage of resistance (> 50 %) to tetracyclines, aminoglycosides, quinolones, trimethoprim and sulphonamides, while resistance to third-generation cephalosporins and colistin remained low (< 25 %). Comparative genomic analysis demonstrated high genetic diversity within production pyramids, although, some clones persisted over time, suggesting transmission within batches. Statistical analyses found no association between genetic traits and farm origins, although outbreaks often involved clones with minimal SNP differences. This study underscores the complexity of E. coli transmission in swine and highlights the need for genomic surveillance to monitor AMR.

Draft genome sequence of a multidrug-resistant Escherichia coli O13/O129:H11 isolate from imported beef in Saudi Arabia

2025-06-17

Othman I. Aljurayyad , Elaf A. Alshdokhi , Mohammed I. Mujallad +7 more | Microbiology Resource Announcements

ABSTRACT Escherichia coli , typically harmless, resides in the gut. However, certain strains are lethal pathogens. Here, we report a draft genome sequence of a multidrug resistance E. coli O13/O129 … ABSTRACT Escherichia coli , typically harmless, resides in the gut. However, certain strains are lethal pathogens. Here, we report a draft genome sequence of a multidrug resistance E. coli O13/O129 (food source) in Saudi Arabia. O-antigen of E. coli O13/O129 is closely related to Shigella flexneri (causative agent of shigellosis).

Serogroup Prevalence, Virulence Profile and Antibiotic Resistance of Avian Pathogenic Escherichia coli Isolated from Broiler Chicken

2025-06-16

Showkat Ahmad Shah , Masood Saleem Mir , Shayaib A. Kamil +7 more | Veterinary Sciences

Avian pathogenic Escherichia coli (APEC) causes avian colibacillosis, leading to significant economic losses and concerns for food safety in the poultry industry. This study focused on examining the virulence gene … Avian pathogenic Escherichia coli (APEC) causes avian colibacillosis, leading to significant economic losses and concerns for food safety in the poultry industry. This study focused on examining the virulence gene profile, antibiotic resistance prevalence, and resistance patterns of APEC isolates. A total of 250 bacterial strains were collected from birds affected by colibacillosis. Serogrouping revealed diverse serotypes, with O2 being the most common (16%), followed by O1, O8, and O76. All isolates tested positive for at minimum one virulence gene, with 7.2% carrying all five targeted genes, particularly in serogroups O1, O8, O45, and O88. The most detected gene was iss, present in 79.6% of isolates, followed by tsh, iucC, sitA, and papC. The antibiotic resistance analysis showed that all isolates exhibited multidrug resistance, although they remained susceptible to gentamicin, amikacin, ciprofloxacin, and chloramphenicol. Moreover, specific antibiotic resistance genes were known in the isolates, with tetA detected in 54.8%, tetB in 51.7%, sul1 in 50%, and aadA1 in 29.2%. These findings highlight the widespread antibiotic resistance in chicken carcasses, which poses a hazard to human health in terms of transfer of resistance to humans, reduced effectiveness of antibiotics and impaired ability to contain infectious diseases. Therefore, it is crucial to implement strict monitoring programs to regulate antibiotic usage in poultry production.

Genome-wide Screening of the Escherichia coli Keio Knockout Collection Identifies Genetic Determinants of Epetraborole Hypersusceptibility

2025-06-13

Anara Babayeva , Bekir Çöl | European Journal of Clinical Microbiology & Infectious Diseases

Complete sequence of the avian pathogenic Escherichia coli strain VTB96933v containing a novel conjugative antimicrobial resistance and virulence IncI1-ST114-ColBM plasmid

2025-06-12

Zhuohao Wang , David J. Gerber , Vincent Perreten | Microbiology Resource Announcements

ABSTRACT The complete sequence of a South African avian pathogenic Escherichia coli was obtained through short and long read consensus-based assembly. It consists of a 5,120,371 bp chromosome and two … ABSTRACT The complete sequence of a South African avian pathogenic Escherichia coli was obtained through short and long read consensus-based assembly. It consists of a 5,120,371 bp chromosome and two plasmids, one of 86,932 and the other of 161,786 bp. The latter is a novel conjugative ColBM plasmid type IncI1-ST114, containing antimicrobial resistance and APEC-associated virulence genes.

Enteropathogenic Escherichia coli revisited - new insights into old EPEC isolates using whole genome sequencing

2025-06-12

Alexander Kehl , Lynette Bader , Agnes Kaiping +4 more | International Journal of Medical Microbiology

Enterohemorrhagic E. coli (EHEC) and the microbiome

2025-06-12

Quentin Perraud , Vanessa Sperandio | PLoS Pathogens

LDL receptor–mediated endocytosis of Escherichia coli α-hemolysin mediates renal epithelial toxicity

2025-06-12

Hunter W. Kuhn , Madeleine R. Smither , Rachel J. Jin +6 more | Proceedings of the National Academy of Sciences

The α-hemolysin (HlyA) of uropathogenic Escherichia coli (UPEC) is a pore-forming toxin (PFT) that is thought to function by disrupting the host cell plasma membrane. Although CD18 (LFA-1) has been … The α-hemolysin (HlyA) of uropathogenic Escherichia coli (UPEC) is a pore-forming toxin (PFT) that is thought to function by disrupting the host cell plasma membrane. Although CD18 (LFA-1) has been implicated as a receptor on myeloid cells, the mechanisms underlying HlyA cytotoxicity to epithelial cells are poorly defined. Here, we show that HlyA secretion by UPEC markedly intensifies renal tubular epithelial injury in a murine model of ascending pyelonephritis. A CRISPR-Cas9 loss-of-function screen in renal collecting duct cells revealed an unexpected requirement for clathrin-mediated endocytosis in HlyA-induced cytotoxicity. Following internalization, HlyA triggered lysosomal permeabilization, resulting in protease leakage, cytoplasmic acidification, and mitochondrial impairment, culminating in rapid epithelial cell death—a pathway distinct from canonical membrane-disrupting mechanisms of other PFTs. Moreover, we identify the low-density lipoprotein receptor (LDLR) as a critical epithelial receptor for HlyA; genetic ablation or competitive inhibition of the HlyA–LDLR interaction fully abrogated cytotoxicity. Our findings detail a paradigm for HlyA function in which epithelial toxicity relies on LDLR-mediated endocytic uptake rather than plasma membrane poration. These mechanistic insights illuminate potential therapeutic strategies to attenuate HlyA-mediated tissue damage during UPEC infections.

Design of a Targeted Amplicon Sequencing Panel for Detection of Foodborne Pathogens and its Application in Detection of Spiked Shiga Toxin-Producing Escherichia coli in Romaine Lettuce

2025-06-12

Isha R. Patel , Mark K. Mammel , Jayanthi Gangiredla +1 more | Research Square (Research Square)

<title>Abstract</title> Background: Contamination of leafy greens with foodborne pathogens like Shiga toxin–producing <italic>Escherichia coli</italic> (STEC) poses a public health concern as 40 documented outbreaks in the United States and Canada … <title>Abstract</title> Background: Contamination of leafy greens with foodborne pathogens like Shiga toxin–producing <italic>Escherichia coli</italic> (STEC) poses a public health concern as 40 documented outbreaks in the United States and Canada occurred between 2009–2018. Early detection and identification of foodborne pathogens helps mitigate outbreaks. One way to implement this is through the application of next-generation sequencing (NGS) methods which offer high throughput, resolution, and sensitivity for both detection and identification of foodborne pathogens. Here we demonstrate the use of a custom targeted amplicon sequencing (TAS) panel targeting 135 known human foodborne pathogens. Despite the scope and power of NGS methods, technical challenges remain in detecting low levels of pathogens in contaminated food. Using a quasimetagenomics approach, this study demonstrates that compared to whole metagenomic sequencing (WMS), targeted amplicon sequencing (TAS) is a rapid and sensitive NGS based method for detecting low levels of pathogens as demonstrated with spiked STEC in bagged chopped ready-to-eat (RTE) romaine lettuce. Results Here we evaluate the utility, specificity, and limit of detection of a targeted amplicon sequencing (TAS) approach for detection and identification of STEC in spiked RTE romaine lettuce. Romaine lettuce was inoculated with STEC at different concentrations. Post inoculation, cells were harvested using a modified version of the Bacteriological Analytical Methods (BAM), at 0.5 h, 5 h and 6 h from primary enrichments and DNA was isolated. DNA libraries were prepared for whole metagenome sequencing (WMS) as well as TAS. Data obtained indicate that TAS is more sensitive than WMS at not only detecting the pathogen at the species level, but also at detecting virulence markers such as <italic>stx1</italic> and <italic>stx2.</italic> Conclusions The targeted sequencing approach described here provides a rapid and sensitive molecular method to detect and identify foodborne pathogenic bacteria. As proof of principle, we use STEC spiked RTE romaine lettuce to demonstrate the applicability of TAS in foodborne pathogen detection.

The fusion subunit vaccine L-DBF protects aged mice against heterologous lethal Shigella challenge after prior exposure

2025-06-05

Md. Shafiullah Parvej , Ti Lu , Suhrid Maiti +7 more | Frontiers in Immunology

Shigellosis is among the top causes of bacterial diarrhea with significantly high morbidity and mortality for children under five years of age in low- and middle-income countries. Unfortunately, there are … Shigellosis is among the top causes of bacterial diarrhea with significantly high morbidity and mortality for children under five years of age in low- and middle-income countries. Unfortunately, there are currently no licensed vaccines to prevent shigellosis. Our laboratory has developed the protein-based subunit vaccine candidate L-DBF by fusing the type III secretion system proteins IpaB and IpaD with the mucosal adjuvant LTA1, the active moiety of the heat-labile toxin from enterotoxigenic Escherichia coli . L-DBF delivered intranasally has been shown to protect against multiple serotypes of Shigella using the lethal pulmonary mice model. In recent work, we showed that even following prior infection with two sublethal doses of S. flexneri 2a in adult mice, L-DBF effectively cross-protects mice from a potentially lethal challenge with S. sonnei in addition to S. flexneri . We therefore wanted to know whether a prior sublethal infection by S. flexneri or S. sonnei would impact the protective immune response elicited by L-DBF against heterologous lethal infections in an aged mouse model. Elderly mice were subjected to a single sublethal dose of S. flexneri or S. sonnei prior to vaccination with L-DBF. We found that pre-exposed mice receiving L-DBF developed heterologous cross-protection against both S. flexneri and S. sonnei lethal challenge doses. This contrasts with unvaccinated mice that succumbed to the lethal challenge, despite a single homologous or heterologous pre-exposure to Shigella spp. Thus, L-DBF is a strong candidate for a protective shigellosis vaccine in all age groups to protect against commonly encountered Shigella serotypes in both naïve hosts and those pre-exposed with homologous or heterologous Shigella serotypes.

The control strategies for E. coli O157:H7 in food processing at the physical, chemical and biological levels

2025-06-05

CM Xu , Z. Xin , Roch‐Chui Yu +3 more | Frontiers in Microbiology

In recent years, the infectious diseases caused by pathogenic microorganisms have become one of the most prominent public health issues, which seriously endangers people’s lives and leads to significant economic … In recent years, the infectious diseases caused by pathogenic microorganisms have become one of the most prominent public health issues, which seriously endangers people’s lives and leads to significant economic losses. Studies have shown that the Shiga toxin produced by Escherichia coli O157:H7 ( E. coli O157:H7) can cause severe diseases, such as hemorrhagic colitis, diarrhea, hemolytic uremic syndrome, etc. For the purpose of improving people’s health level and quality of life, it is quite important and necessary to further deepen the research on the antibacterial methods for pathogenic bacteria. In this work, we mainly summarized the control strategies for E. coli O157:H7 in food processing from the physical, chemical and biological levels, and summarized their own antibacterial mechanisms as well as the advantages and weaknesses. In general, physical methods are effective in eliminating E. coli O157:H7, but some are costly, complex, and may compromise food quality. Chemical methods, such as acidic preservatives and chlorine-based disinfectants, can also pose health risks with long-term and excessive use. In contrast, biological methods, although somewhat expensive, tend to provide safer and more environmentally friendly approaches with effective antimicrobial effects.

Vat-Mediated Mucus Penetration Enables Genotoxic Activity of pks+ Escherichia coli

2025-06-03

Héloïse Chat , Léa Girondier , Guillaume Dalmasso +7 more | International Journal of Molecular Sciences

Colibactin toxin-producing Escherichia coli (pks+ E. coli) strains are associated with the occurrence of colorectal cancer in humans. These strains induce DNA damage when in close contact with the cells … Colibactin toxin-producing Escherichia coli (pks+ E. coli) strains are associated with the occurrence of colorectal cancer in humans. These strains induce DNA damage when in close contact with the cells of the intestinal epithelium. Therefore, maintaining the integrity of the mucus layer that covers the intestinal epithelial mucosa is crucial for counteracting the effects of colibactin. The Vat protein is a mucin protease capable of degrading MUC2 mucus proteins that was previously described in adherent and invasive Escherichia coli strains. Our work shows that the vat gene is found in the genome of all pks+ E. coli strains isolated from patients with colon cancer. In mucus-producing HT29-16E cells, we demonstrated that the Vat protein of E. coli pks+ allows bacteria to penetrate mucus and to reach the epithelial cells. Cells infected with the E. coli pks + vat- strain show a reduction in γ-H2AX staining, a marker of DNA damage. Infection of ApcMin/+ mice with the E. coli pks + vat+ strain or the E. coli pks + vat- mutant revealed that Vat enhances the ability of pks+ E. coli strains to colonize the intestinal mucosa and, in turn, their pro-carcinogenic effects. This study reveals that Vat promotes crossing of the intestinal mucus layer, gut colonization, and the carcinogenicity of pks+ E. coli.

Comment on: A case of intercurrent shigellosis and rectal gonorrhea in an acutely unwell febrile returned traveler by Fuller et al.

2025-06-01

Robert Taylor , Lewis C. E. Mason , Claire Jenkins +3 more | Therapeutic Advances in Infectious Disease

Genomic epidemiology of avian pathogenic Escherichia coli in two broiler colibacillosis outbreaks in Finland

2025-06-01

Mia Biström , Pia Vennerström , Taru Lienemann +3 more | Veterinary Microbiology

Regulatory Role of ISEcp1 and Spacer Sequences in blaCTX-M-Mediated Cephalosporin Resistance in Shigella

2025-06-01

Hui Zhang , Siyu He , Xin Pang +5 more | Journal of Global Antimicrobial Resistance

Extended-spectrum β-lactamases, especially CTX-M enzymes, play a critical role in cephalosporin resistance in several bacterial species. The ISEcp1 insertion sequence, a mobile genetic element, regulates the high expression and horizontal … Extended-spectrum β-lactamases, especially CTX-M enzymes, play a critical role in cephalosporin resistance in several bacterial species. The ISEcp1 insertion sequence, a mobile genetic element, regulates the high expression and horizontal transfer of the blaCTX-M gene. Diverse types of spacer regions exist, the length of which varies across the different types of blaCTX-M genes and their upstream ISEcp1 elements. In this study, we aimed to investigate the distribution and role of ISEcp1 and different length spacers in antibiotic-resistant Shigella. We selected 1,393 cephalosporin-resistant Shigella strains isolated from China between 2004 and 2016 to analyze the distribution of ISEcp1 and spacers using PCR and sequencing. To functionally evaluate the role of these elements, we designed different combinations of ISEcp1, spacer sequences, and blaCTX-M gene fragments to generate and express recombinant plasmids containing these fragments in Escherichia coli. We then assessed the cephalosporin resistance phenotype of recombinant clones using the E-TEST method. The carriage rate of ISEcp1 in cephalosporin-resistant Shigella was 90.09%, with an ISEcp1-CTX-M element carriage rate of 67.19%, and was significantly higher in the blaCTX-M-9 group than that in the blaCTX-M-1 group. Moreover, E. coli strains containing different combinations exhibited varying bacterial resistance to β-lactam antibiotics, indicating the regulatory role of ISEcp1 and spacers. Our results demonstrate that the configuration of ISEcp1, spacer sequences, and blaCTX-M in plasmids fosters a robust resistance phenotype against various cephalosporins, providing new insights into antimicrobial resistance mechanisms and an important basis for developing novel anti-resistance drugs.

Mass spectrometric analysis of lipid-linked oligosaccharide heterogeneity in genetically modified E. coli used for glycoconjugate bacterial vaccine production

2025-06-01

Leva Palubeckaite , Alan B. Moran , Dario A. T. Cramer +7 more | Carbohydrate Polymers

- Phenotypic and genomic characterization of beta-lactamase-producing Escherichia coli in migratory geese in West Texas, United States

2025-06-01

Yamima Tasnim , Md. Kaisar Rahman , Cherissa Abdul-Hamid +1 more | One Health

Corrigendum to “Distribution of virulence genes and antimicrobial resistance of Escherichia coli isolated from hospitalized neonates: A multi-center study across China” [Heliyon Volume 10, Issue 16, August 30, 2024, Article e35991]

2025-06-01

Yuting Guo , Ruiqi Xiao , Jinxing Feng +7 more | Heliyon