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Súkeníková L, Černý V, Věcek J, Petrásková P, Novotná O, Vobruba Š, Michalčíková T, Procházka J, Kolářová L, Prokešová L, Hrdý J. The Impact of Escherichia coli Probiotic Strain O83:K24:H31 on the Maturation of Dendritic Cells and Immunoregulatory Functions In Vitro and In Vivo. Cells 2022; 11:cells11101624. [PMID: 35626660 PMCID: PMC9140140 DOI: 10.3390/cells11101624] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/27/2022] [Accepted: 05/07/2022] [Indexed: 11/25/2022] Open
Abstract
Early postnatal events are important for the development of the neonatal immune system. Harboring the pioneering microorganisms forming the microbiota of the neonatal gastrointestinal tract is important for priming the immune system, as well as inducing appropriate tolerance to the relatively innocuous environmental antigens and compounds of normal healthy microbiota. Early postnatal supplementation of suitable, safe probiotics could accelerate this process. In the current study, the immunomodulatory capacity of the probiotic strain of Escherichia coli O83:K24:H31 (EcO83) was characterized in vitro and in vivo. We compared the capacity of EcO83 with and without hemolytic activity on selected immune characteristics in vitro as determined by flow cytometry and quantitative real-time PCR. Both strains with and without hemolytic activity exerted comparable capacity on the maturation of dendritic cells while preserving the induction of interleukin 10 (Il10) expression in dendritic cells and T cells cocultured with EcO83 primed dendritic cells. Early postnatal supplementation with EcO83 led to massive but transient colonization of the neonatal gastrointestinal tract, as detected by in vivo bioimaging. Early postnatal EcO83 administration promoted gut barrier function by increasing the expression of claudin and occludin and the expression of Il10. Early postnatal EcO83 application promotes maturation of the neonatal immune system and promotes immunoregulatory and gut barrier functions.
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Affiliation(s)
- Lenka Súkeníková
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
- Faculty of Science, Charles University, 128 00 Prague, Czech Republic
| | - Viktor Černý
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
| | - Jan Věcek
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
| | - Petra Petrásková
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
| | - Olga Novotná
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
| | - Šimon Vobruba
- Czech Academy of Sciences, 142 20 Prague, Czech Republic;
| | - Tereza Michalčíková
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, 252 50 Vestec, Czech Republic; (T.M.); (J.P.)
| | - Jan Procházka
- Czech Centre for Phenogenomics, Institute of Molecular Genetics, Czech Academy of Sciences, 252 50 Vestec, Czech Republic; (T.M.); (J.P.)
| | - Libuše Kolářová
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
| | - Ludmila Prokešová
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
| | - Jiří Hrdý
- First Faculty of Medicine, Charles University and General University Hospital, 121 08 Prague, Czech Republic; (L.S.); (V.Č.); (J.V.); (P.P.); (O.N.); (L.K.); (L.P.)
- Correspondence: ; Tel.: +420-224968473
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Zwicker C, Sarate P, Drinić M, Ambroz K, Korb E, Smole U, Köhler C, Wilson MS, Kozakova H, Sebo P, Kverka M, Wiedermann U, Schabussova I. Prophylactic and therapeutic inhibition of allergic airway inflammation by probiotic Escherichia coli O83. J Allergy Clin Immunol 2018; 142:1987-1990.e7. [DOI: 10.1016/j.jaci.2018.07.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 07/15/2018] [Accepted: 07/31/2018] [Indexed: 11/26/2022]
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Chamoun MN, Sullivan MJ, Ulett GC. Quantification of bacteriuria caused by Hemolysin-positive Escherichia coli in human and mouse urine using quantitative polymerase chain reaction (qPCR) targeting hlyD. J Microbiol Methods 2018; 152:173-178. [DOI: 10.1016/j.mimet.2018.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/10/2018] [Accepted: 08/12/2018] [Indexed: 12/21/2022]
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Wassenaar TM. Insights from 100 Years of Research with Probiotic E. Coli. Eur J Microbiol Immunol (Bp) 2016; 6:147-161. [PMID: 27766164 PMCID: PMC5063008 DOI: 10.1556/1886.2016.00029] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 01/03/2023] Open
Abstract
A century ago, Alfred Nissle discovered that intentional intake of particular strains of Escherichia coli could treat patients suffering from infectious diseases. Since then, one of these strains became the most frequently used probiotic E. coli in research and was applied to a variety of human conditions. Here, properties of that E. coli Nissle 1917 strain are compared with other commercially available E. coli probiotic strains, with emphasis on their human applications. A literature search formed the basis of a summary of research findings reported for the probiotics Mutaflor, Symbioflor 2, and Colinfant. The closest relatives of the strains in these products are presented, and their genetic content, including the presence of virulence, genes is discussed. A similarity to pathogenic strains causing urinary tract infections is noticeable. Historic trends in research of probiotics treatment for particular human conditions are identified. The future of probiotic E. coli may lay in what Alfred Nissle originally discovered: to treat gastrointestinal infections, which nowadays are often caused by antibiotic-resistant pathogens.
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Affiliation(s)
- Trudy M. Wassenaar
- Molecular Microbiology and Genomics Consultants, Tannenstrasse 7, 55576 Zotzenheim, Germany
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Crémet L, Broquet A, Brulin B, Jacqueline C, Dauvergne S, Brion R, Asehnoune K, Corvec S, Heymann D, Caroff N. Pathogenic potential of Escherichia coli clinical strains from orthopedic implant infections towards human osteoblastic cells. Pathog Dis 2015; 73:ftv065. [PMID: 26333570 DOI: 10.1093/femspd/ftv065] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2015] [Indexed: 01/18/2023] Open
Abstract
Escherichia coli is one of the first causes of Gram-negative orthopedic implant infections (OII), but little is known about the pathogenicity of this species in such infections that are increasing due to the ageing of the population. We report how this pathogen interacts with human osteoblastic MG-63 cells in vitro, by comparing 20 OII E. coli strains to two Staphylococcus aureus and two Pseudomonas aeruginosa strains. LDH release assay revealed that 6/20 (30%) OII E. coli induced MG-63 cell lysis whereas none of the four control strains was cytotoxic after 4 h of coculture. This high cytotoxicity was associated with hemolytic properties and linked to hlyA gene expression. We further showed by gentamicin protection assay and confocal microscopy that the non-cytotoxic E. coli were not able to invade MG-63 cells unlike S. aureus strains (internalization rate <0.01% for the non-cytotoxic E. coli versus 8.88 ± 2.31% and 4.60 ± 0.42% for both S. aureus). The non-cytotoxic E. coli also demonstrated low adherence rates (<7%), the most adherent E. coli eliciting higher IL-6 and TNF-α mRNA expression in the osteoblastic cells. Either highly cytotoxic or slightly invasive OII E. coli do not show the same infection strategies as S. aureus towards osteoblasts.
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Affiliation(s)
- Lise Crémet
- UPRES EA3826, Laboratory of Clinical and Experimental Therapeutics of Infections., Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France Department of Bacteriology-Hygiene, Nantes University Hospital, F-44000 Nantes, France
| | - Alexis Broquet
- UPRES EA3826, Laboratory of Clinical and Experimental Therapeutics of Infections., Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France
| | - Bénédicte Brulin
- INSERM, UMR 957, Pathophysiology of Bone Resorption Laboratory and Therapy of Primary Bone Tumors, Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France
| | - Cédric Jacqueline
- UPRES EA3826, Laboratory of Clinical and Experimental Therapeutics of Infections., Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France
| | - Sandie Dauvergne
- UPRES EA3826, Laboratory of Clinical and Experimental Therapeutics of Infections., Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France
| | - Régis Brion
- INSERM, UMR 957, Pathophysiology of Bone Resorption Laboratory and Therapy of Primary Bone Tumors, Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France
| | - Karim Asehnoune
- UPRES EA3826, Laboratory of Clinical and Experimental Therapeutics of Infections., Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France Department of Bacteriology-Hygiene, Nantes University Hospital, F-44000 Nantes, France INSERM, UMR 957, Pathophysiology of Bone Resorption Laboratory and Therapy of Primary Bone Tumors, Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France Intensive Care Unit, Anesthesia and Critical Care Department, Nantes University Hospital, F-44000 Nantes, France
| | - Stéphane Corvec
- UPRES EA3826, Laboratory of Clinical and Experimental Therapeutics of Infections., Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France Department of Bacteriology-Hygiene, Nantes University Hospital, F-44000 Nantes, France
| | - Dominique Heymann
- INSERM, UMR 957, Pathophysiology of Bone Resorption Laboratory and Therapy of Primary Bone Tumors, Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France
| | - Nathalie Caroff
- UPRES EA3826, Laboratory of Clinical and Experimental Therapeutics of Infections., Medicine Faculty, University of Nantes, 1, rue G. Veil, F-44000 Nantes, France
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Ristow LC, Welch RA. Hemolysin of uropathogenic Escherichia coli: A cloak or a dagger? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:538-45. [PMID: 26299820 DOI: 10.1016/j.bbamem.2015.08.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/05/2015] [Accepted: 08/18/2015] [Indexed: 01/27/2023]
Abstract
Hemolysin from uropathogenic Escherichia coli (UPEC) is a hemolytic and cytotoxic protein active against a broad range of species and cell types. Expression of hemolysin correlates with severity of infection, as up to 78% of UPEC isolates from pyelonephritis cases express hemolysin. Despite decades of research on hemolysin activity, the mechanism of intoxication and the function of hemolysin in UPEC infection remain elusive. Early in vitro research established the role of hemolysin as a lytic protein at high doses. It is hypothesized that hemolysin is secreted at sublytic doses in vivo and recent research has focused on understanding the more subtle effects of hemolysin both in vitro and in elegant infection models in vivo, including inoculation by micropuncture of individual kidney nephrons. As the field continues to evolve, comparisons of hemolysin function in isolates from a range of UTI infections will be important for delineating the role of this toxin. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Laura C Ristow
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Rodney A Welch
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA.
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Rödiger S, Kramer T, Frömmel U, Weinreich J, Roggenbuck D, Guenther S, Schaufler K, Schröder C, Schierack P. Intestinal Escherichia coli colonization in a mallard duck population over four consecutive winter seasons. Environ Microbiol 2015; 17:3352-61. [PMID: 25684458 DOI: 10.1111/1462-2920.12807] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/31/2015] [Accepted: 02/01/2015] [Indexed: 01/04/2023]
Abstract
We report the population structure and dynamics of one Escherichia coli population of wild mallard ducks in their natural environment over four winter seasons, following the characterization of 100 isolates each consecutive season. Macro-restriction analysis was used to define isolates variously as multi- or 1-year pulsed-field gel electrophoresis (PFGE) types. Isolates were characterized genotypically based on virulence-associated genes (VAGs), phylogenetic markers, and phenotypically based on haemolytic activity, antimicrobial resistance, adhesion to epithelial cells, microcin production, motility and carbohydrate metabolism. Only 12 out of 220 PFGE types were detectable over more than one winter, and classified as multi-year PFGE types. There was a dramatic change of PFGE types within two winter seasons. Nevertheless, the genetic pool (VAGs) and antimicrobial resistance pattern remained remarkably stable. The high diversity and dynamics of this E. coli population were also demonstrated by the occurrence of PFGE subtypes and differences between isolates of one PFGE type (based on VAGs, antimicrobial resistance and adhesion rates). Multi- and 1-year PFGE types differed in antimicrobial resistance, VAGs and adhesion. Other parameters were not prominent colonization factors. In conclusion, the high diversity, dynamics and stable genetic pool of an E. coli population seem to enable their successful colonization of host animal population over time.
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Affiliation(s)
- Stefan Rödiger
- Fakultät für Naturwissenschaften, Brandenburgische Technische Universität Cottbus - Senftenberg, Großenhainer Str. 57, 01968, Senftenberg, Germany
| | - Toni Kramer
- Fakultät für Naturwissenschaften, Brandenburgische Technische Universität Cottbus - Senftenberg, Großenhainer Str. 57, 01968, Senftenberg, Germany
| | - Ulrike Frömmel
- Fakultät für Naturwissenschaften, Brandenburgische Technische Universität Cottbus - Senftenberg, Großenhainer Str. 57, 01968, Senftenberg, Germany
| | - Jörg Weinreich
- Fakultät für Naturwissenschaften, Brandenburgische Technische Universität Cottbus - Senftenberg, Großenhainer Str. 57, 01968, Senftenberg, Germany
| | - Dirk Roggenbuck
- Fakultät für Naturwissenschaften, Brandenburgische Technische Universität Cottbus - Senftenberg, Großenhainer Str. 57, 01968, Senftenberg, Germany.,GA Generic Assays GmbH, Ludwig-Erhard-Ring 3, 15827, Dahlewitz, Germany
| | - Sebastian Guenther
- Institute of Microbiology and Epizootics, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - Katharina Schaufler
- Institute of Microbiology and Epizootics, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - Christian Schröder
- Fakultät für Naturwissenschaften, Brandenburgische Technische Universität Cottbus - Senftenberg, Großenhainer Str. 57, 01968, Senftenberg, Germany
| | - Peter Schierack
- Fakultät für Naturwissenschaften, Brandenburgische Technische Universität Cottbus - Senftenberg, Großenhainer Str. 57, 01968, Senftenberg, Germany
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Enderle JL, Miller AL, Pyles RB. Quantification of bacterial uropathogens in preclinical samples using real-time PCR assays. Curr Microbiol 2013; 68:220-6. [PMID: 24114413 DOI: 10.1007/s00284-013-0465-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 08/23/2013] [Indexed: 12/21/2022]
Abstract
Uropathogenic Escherichia coli (UPEC) and Staphylococcus saprophyticus (S. saprophyticus) are responsible for the majority of community-acquired urinary tract infections (UTI). Agar plating, a gold standard for detection of bacterial uropathogens, is labor intensive, limited for distinguishing between environmental contaminants and pathogens, and fails to effectively detect mixed infections. A reliable method for specific and sensitive quantitative assessment of infections would allow cost-effective evaluation of large numbers of experimental samples. A methodology such as quantitative PCR (qPCR) addresses the limitations of agar plating. We developed and validated highly specific and sensitive qPCR assays to assist researchers in the evaluation of potential vaccines and interventions in preclinical models of UPEC and S. saprophyticus UTI. The developed UPEC PCR targeted a highly conserved region of the UPEC hemolysin D (hlyD) gene that reproducibly detected type strains CFT073 and J96 over a 9 log range with high precision. To quantify S. saprophyticus genomes, a separate qPCR assay targeting the Trk transport gene was developed with an 8 log range. Neither assay detected bacterial species predicted to be sample contaminants. Using our optimized workflow that includes automated steps, up to 200 urine or tissue samples can be processed in as few as 3 h. Additionally, sequence comparisons of our primers and probe to other UTI bacterial strains indicated the broad applicability of these assays. These optimized qPCR assays provide a cost-effective and time-saving method for quantification of bacterial burdens in tissues and body fluids to assess the effectiveness of candidate vaccines or interventions.
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Affiliation(s)
- Janet L Enderle
- University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77554-0436, USA,
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Wiles TJ, Mulvey MA. The RTX pore-forming toxin α-hemolysin of uropathogenic Escherichia coli: progress and perspectives. Future Microbiol 2013; 8:73-84. [PMID: 23252494 DOI: 10.2217/fmb.12.131] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Members of the RTX family of protein toxins are functionally conserved among an assortment of bacterial pathogens. By disrupting host cell integrity through their pore-forming and cytolytic activities, this class of toxins allows pathogens to effectively tamper with normal host cell processes, promoting pathogenesis. Here, we focus on the biology of RTX toxins by describing salient properties of a prototype member, α-hemolysin, which is often encoded by strains of uropathogenic Escherichia coli. It has long been appreciated that RTX toxins can have distinct effects on host cells aside from outright lysis. Recently, advances in modeling and analysis of host-pathogen interactions have led to novel findings concerning the consequences of pore formation during host-pathogen interactions. We discuss current progress on longstanding questions concerning cell specificity and pore formation, new areas of investigation that involve toxin-mediated perturbations of host cell signaling cascades and perspectives on the future of RTX toxin investigation.
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Affiliation(s)
- Travis J Wiles
- Division of Microbiology & Immunology, Pathology Department, University of Utah, 15 North Medical Drive East #2100, Salt Lake City, UT 84112-0565, USA
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10
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General and molecular microbiology and microbial genetics in the IM CAS. J Ind Microbiol Biotechnol 2010; 37:1227-39. [DOI: 10.1007/s10295-010-0859-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 08/20/2010] [Indexed: 11/28/2022]
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Floyd RV, Winstanley C, Bakran A, Wray S, Burdyga TV. Modulation of ureteric Ca signaling and contractility in humans and rats by uropathogenic E. coli. Am J Physiol Renal Physiol 2010; 298:F900-8. [PMID: 20130119 DOI: 10.1152/ajprenal.00468.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ascending urinary tract infections, a significant cause of kidney damage, are predominantly caused by uropathogenic Escherichia coli (UPEC). However, the role and mechanism of changes in ureteric function during infection are poorly understood. We therefore investigated the effects of UPEC on Ca signaling and contractions in rat (n = 17) and human (n = 6) ureters. Ca transients and force were measured and effects of UPEC on the urothelium were monitored in live tissues. In both species, luminal exposure of ureters to UPEC strains J96 and 536 caused significant time-dependent decreases in phasic and high K depolarization-induced contractility, associated with decreases in the amplitude and duration of the Ca transients. These changes were significant after 3-5 h and irreversible over the next 5 h. The infection causes increased activity of K channels, causing inhibition of voltage-gated Ca entry, and K channel blockers could reverse the effects of UPEC on ureteric function. A smaller direct effect on Ca entry also occurs. Nonpathogenic E. coli (TG2) or abluminal application of UPEC did not produce changes in Ca signaling or contractility. UPEC exposure also caused significant impairment of urothelial barrier function; luminal application of the Ca channel blocker nifedipine caused a reduction in contractions as it entered the tissue, an effect not observed in untreated ureters. Thus, UPEC impairs ureteric contractility in a Ca-dependent manner, largely caused by stimulation of potassium channels and this mechanism is dependent on host-urothelium interaction.
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Affiliation(s)
- Rachel V Floyd
- Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool, UK.
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Hemolysin of uropathogenic Escherichia coli evokes extensive shedding of the uroepithelium and hemorrhage in bladder tissue within the first 24 hours after intraurethral inoculation of mice. Infect Immun 2008; 76:2978-90. [PMID: 18443089 DOI: 10.1128/iai.00075-08] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many uropathogenic Escherichia coli (UPEC) strains produce both hemolysin (Hly) and cytotoxic necrotizing factor type 1 (CNF1), and the loci for these toxins are often linked. The conclusion that Hly and CNF1 contribute to urovirulence is supported by the results of epidemiological studies associating the severity of urinary tract infections (UTIs) with toxin production by UPEC isolates. Additionally, we previously reported that mouse bladders and rat prostates infected with UPEC strain CP9 exhibit a more profound inflammatory response than the organs from animals challenged with CP9cnf(1) and that CNF1 decreases the antimicrobial activities of polymorphonuclear leukocytes. More recently, we created an Hly mutant, CP9Delta hlyA(1)::cat, and showed that it was less hemolytic and destructive for cultured bladder cells than CP9 was. Here we evaluated the relative effects of mutations in hlyA(1) or cnf(1) alone or together on the pathogenicity of CP9 in a mouse model of ascending UTI. To do this, we constructed an hlyA(1)-complemented clone of CP9Delta hlyA(1)::cat and an hlyA(1) cnf(1) CP9 double mutant. We found that Hly had no influence on bacterial colonization of the bladder or kidneys in single or mixed infections with the wild type and CP9Delta hlyA(1)::cat but that it did provoke sloughing of the uroepithelium and bladder hemorrhage within the first 24 h after challenge. Finally, we confirmed that CNF1 expression induces bladder inflammation and, in particular, as shown in this study, submucosal edema. From these data, we speculate that Hly and CNF1 may be largely responsible for the signs and symptoms of cystitis in humans infected with toxigenic UPEC.
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