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Sheng H, Ndeddy Aka RJ, Wu S. Lipopolysaccharide Core Truncation in Invasive Escherichia coli O157:H7 ATCC 43895 Impairs Flagella and Curli Biosynthesis and Reduces Cell Invasion Ability. Int J Mol Sci 2024; 25:9224. [PMID: 39273173 PMCID: PMC11394844 DOI: 10.3390/ijms25179224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Revised: 08/22/2024] [Accepted: 08/24/2024] [Indexed: 09/15/2024] Open
Abstract
Escherichia coli O157:H7 (E. coli O157) is known for causing severe foodborne illnesses such as hemorrhagic colitis and hemolytic uremic syndrome. Although E. coli O157 is typically regarded as an extracellular pathogen and a weak biofilm producer, some E. coli O157 strains, including a clinical strain ATCC 43895, exhibit a notable ability to invade bovine crypt cells and other epithelial cells, as well as to form robust biofilm. This invasive strain persists in the bovine host significantly longer than non-invasive strains. Various surface-associated factors, including lipopolysaccharides (LPS), flagella, and other adhesins, likely contribute to this enhanced invasiveness and biofilm formation. In this study, we constructed a series of LPS-core deletion mutations (waaI, waaG, waaF, and waaC) in E. coli O157 ATCC 43895, resulting in stepwise truncations of the LPS. This approach enabled us to investigate the effects on the biosynthesis of key surface factors, such as flagella and curli, and the ability of this invasive strain to invade host cells. We confirmed the LPS structure and found that all LPS-core mutants failed to form biofilms, highlighting the crucial role of core oligosaccharides in biofilm formation. Additionally, the LPS inner-core mutants ΔwaaF and ΔwaaC lost the ability to produce flagella and curli. Furthermore, these inner-core mutants exhibited a dramatic reduction in adherence to and invasion of epithelial cells (MAC-T), showing an approximately 100-fold decrease in cell invasion compared with the outer-core mutants (waaI and waaG) and the wild type. These findings underscore the critical role of LPS-core truncation in impairing flagella and curli biosynthesis, thereby reducing the invasion capability of E. coli O157 ATCC 43895.
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Affiliation(s)
- Haiqing Sheng
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID 83844, USA
| | - Robinson J Ndeddy Aka
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID 83844, USA
| | - Sarah Wu
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID 83844, USA
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Qin J, Hong Y, Morona R, Totsika M. O antigen biogenesis sensitises Escherichia coli K-12 to bile salts, providing a plausible explanation for its evolutionary loss. PLoS Genet 2023; 19:e1010996. [PMID: 37792901 PMCID: PMC10578602 DOI: 10.1371/journal.pgen.1010996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 10/16/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023] Open
Abstract
Escherichia coli K-12 is a model organism for bacteriology and has served as a workhorse for molecular biology and biochemistry for over a century since its first isolation in 1922. However, Escherichia coli K-12 strains are phenotypically devoid of an O antigen (OAg) since early reports in the scientific literature. Recent studies have reported the presence of independent mutations that abolish OAg repeating-unit (RU) biogenesis in E. coli K-12 strains from the same original source, suggesting unknown evolutionary forces have selected for inactivation of OAg biogenesis during the early propagation of K-12. Here, we show for the first time that restoration of OAg in E. coli K-12 strain MG1655 synergistically sensitises bacteria to vancomycin with bile salts (VBS). Suppressor mutants surviving lethal doses of VBS primarily contained disruptions in OAg biogenesis. We present data supporting a model where the transient presence and accumulation of lipid-linked OAg intermediates in the periplasmic leaflet of the inner membrane interfere with peptidoglycan sacculus biosynthesis, causing growth defects that are synergistically enhanced by bile salts. Lastly, we demonstrate that continuous bile salt exposure of OAg-producing MG1655 in the laboratory, can recreate a scenario where OAg disruption is selected for as an evolutionary fitness benefit. Our work thus provides a plausible explanation for the long-held mystery of the selective pressure that may have led to the loss of OAg biogenesis in E. coli K-12; this opens new avenues for exploring long-standing questions on the intricate network coordinating the synthesis of different cell envelope components in Gram-negative bacteria.
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Affiliation(s)
- Jilong Qin
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Yaoqin Hong
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Renato Morona
- School of Biological Sciences, Department of Molecular & Biomedical Sciences, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
| | - Makrina Totsika
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane, Queensland, Australia
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Pinto G, Minnich SA, Hovde CJ, Oliveira H, Smidt H, Almeida C, Azeredo J. The interactions of bacteriophage Ace and Shiga toxin-producing Escherichia coli during biocontrol. FEMS Microbiol Ecol 2021; 97:fiab105. [PMID: 34329454 PMCID: PMC8492476 DOI: 10.1093/femsec/fiab105] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 07/28/2021] [Indexed: 11/15/2022] Open
Abstract
Strictly lytic phages are considered powerful tools for biocontrol of foodborne pathogens. Safety issues needed to be addressed for the biocontrol of Shiga toxin-producing Escherichia coli (STEC) include: lysogenic conversion, Shiga toxin production through phage induction, and emergence/proliferation of bacteriophage insensitive mutants (BIMs). To address these issues, two new lytic phages, vB_EcoS_Ace (Ace) and vB_EcoM_Shy (Shy), were isolated and characterized for life cycle, genome sequence and annotation, pH stability and efficacy at controlling STEC growth. Ace was efficient in controlling host planktonic cells and did not stimulate the production of the Stx prophage or Shiga toxin. A single dose of phage did not lead to the selection of BIMs. However, when reintroduced, BIMs were detected after 24 h of incubation. The gain of resistance was associated with lower virulence, as a subset of BIMs failed to agglutinate with O157-specific antibody and were more sensitive to human serum complement. BIM's biofilm formation capacity and susceptibility to disinfectants was equal to that of the wild-type strain. Overall, this work demonstrated that phage Ace is a safe biocontrol agent against STEC contamination and that the burden of BIM emergence did not represent a greater risk in environmental persistence and human pathogenicity.
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Affiliation(s)
- Graça Pinto
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
- INIAV, IP-National Institute for Agrarian and Veterinary Research, Rua dos Lagidos, Lugar da Madalena, Vairão, Vila do Conde, Portugal
| | - Scott A Minnich
- Animal Veterinary and Food Science, University of Idaho, Moscow, Idaho, 83844-3025 USA
| | - Carolyn J Hovde
- Animal Veterinary and Food Science, University of Idaho, Moscow, Idaho, 83844-3025 USA
| | - Hugo Oliveira
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Carina Almeida
- INIAV, IP-National Institute for Agrarian and Veterinary Research, Rua dos Lagidos, Lugar da Madalena, Vairão, Vila do Conde, Portugal
| | - Joana Azeredo
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
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Wahlig TA, Stanton E, Godfrey JJ, Stasic AJ, Wong ACL, Kaspar CW. A Single Nucleotide Polymorphism in lptG Increases Tolerance to Bile Salts, Acid, and Staining of Calcofluor-Binding Polysaccharides in Salmonella enterica Serovar Typhimurium E40. Front Microbiol 2021; 12:671453. [PMID: 34149657 PMCID: PMC8208086 DOI: 10.3389/fmicb.2021.671453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
The outer membrane of Salmonella enterica plays an important role in combating stress encountered in the environment and hosts. The transport and insertion of lipopolysaccharides (LPS) into the outer membrane involves lipopolysaccharide transport proteins (LptA-F) and mutations in the genes encoding for these proteins are often lethal or result in the transport of atypical LPS that can alter stress tolerance in bacteria. During studies of heterogeneity in bile salts tolerance, S. enterica serovar Typhimurium E40 was segregated into bile salts tolerant and sensitive cells by screening for growth in TSB with 10% bile salts. An isolate (E40V) with a bile salts MIC >20% was selected for further characterization. Whole-genome sequencing of E40 and E40V using Illumina and PacBio SMRT technologies revealed a non-synonymous single nucleotide polymorphism (SNP) in lptG. Leucine at residue 26 in E40 was substituted with proline in E40V. In addition to growth in the presence of 10% bile salts, E40V was susceptible to novobiocin while E40 was not. Transcriptional analysis of E40 and E40V, in the absence of bile salts, revealed significantly greater (p < 0.05) levels of transcript in three genes in E40V; yjbE (encoding for an extracellular polymeric substance production protein), yciE (encoding for a putative stress response protein), and an uncharacterized gene annotated as an acid shock protein precursor (ASPP). No transcripts of genes were present at a greater level in E40 compared to E40V. Corresponding with the greater level of these transcripts, E40V had greater survival at pH 3.35 and staining of Calcofluor-binding polysaccharide (CBPS). To confirm the SNP in lptG was associated with these phenotypes, strain E40E was engineered from E40 to encode for the variant form of LptG (L26P). E40E exhibited the same differences in gene transcripts and phenotypes as E40V, including susceptibility to novobiocin, confirming the SNP was responsible for these differences.
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Affiliation(s)
- Taylor A Wahlig
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Eliot Stanton
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Jared J Godfrey
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Andrew J Stasic
- U. S. Food and Drug Administration, Center for Biologics Evaluation and Research, Washington, DC, United States
| | - Amy C L Wong
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Charles W Kaspar
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
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Ageorges V, Monteiro R, Leroy S, Burgess CM, Pizza M, Chaucheyras-Durand F, Desvaux M. Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation. FEMS Microbiol Rev 2021; 44:314-350. [PMID: 32239203 DOI: 10.1093/femsre/fuaa008] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/31/2020] [Indexed: 12/11/2022] Open
Abstract
Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.
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Affiliation(s)
- Valentin Ageorges
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Ricardo Monteiro
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Catherine M Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
| | | | - Frédérique Chaucheyras-Durand
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,Lallemand Animal Nutrition SAS, F-31702 Blagnac Cedex, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
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Ali A, Kolenda R, Khan MM, Weinreich J, Li G, Wieler LH, Tedin K, Roggenbuck D, Schierack P. Novel Avian Pathogenic Escherichia coli Genes Responsible for Adhesion to Chicken and Human Cell Lines. Appl Environ Microbiol 2020; 86:e01068-20. [PMID: 32769194 PMCID: PMC7531953 DOI: 10.1128/aem.01068-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 08/02/2020] [Indexed: 12/13/2022] Open
Abstract
Avian pathogenic Escherichia coli (APEC) is a major bacterial pathogen of commercial poultry contributing to extensive economic losses and contamination of the food chain. One of the initial steps in bacterial infection and successful colonization of the host is adhesion to the host cells. A random transposon mutant library (n = 1,300) of APEC IMT 5155 was screened phenotypically for adhesion to chicken (CHIC-8E11) and human (LoVo) intestinal epithelial cell lines. The detection and quantification of adherent bacteria were performed by a modified APEC-specific antibody staining assay using fluorescence microscopy coupled to automated VideoScan technology. Eleven mutants were found to have significantly altered adhesion to the cell lines examined. Mutated genes in these 11 "adhesion-altered mutants" were identified by arbitrary PCR and DNA sequencing. The genes were amplified from wild-type APEC IMT 5155, cloned, and transformed into the respective adhesion-altered mutants, and complementation was determined in adhesion assays. Here, we report contributions of the fdtA, rluD, yjhB, ecpR, and fdeC genes of APEC in adhesion to chicken and human intestinal cell lines. Identification of the roles of these genes in APEC pathogenesis will contribute to prevention and control of APEC infections.IMPORTANCE Avian pathogenic E. coli is not only pathogenic for commercial poultry but can also cause foodborne infections in humans utilizing the same attachment and virulence mechanisms. Our aim was to identify genes of avian pathogenic E. coli involved in adhesion to chicken and human cells in order to understand the colonization and pathogenesis of these bacteria. In contrast to the recent studies based on genotypic and bioinformatics data, we have used a combination of phenotypic and genotypic approaches for identification of novel genes contributing to adhesion in chicken and human cell lines. Identification of adhesion factors remains important, as antibodies elicited against such factors have shown potential to block colonization and ultimately prevent disease as prophylactic vaccines. Therefore, the data will augment the understanding of disease pathogenesis and ultimately in designing strategies against the infections.
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Affiliation(s)
- Aamir Ali
- National Institute for Biotechnology and Genetic Engineering College, Pakistan Institute of Engineering and Applied Sciences (NIBGE-C, PIEAS), Faisalabad, Pakistan
- Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
| | - Rafał Kolenda
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Muhammad Moman Khan
- Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
| | - Jörg Weinreich
- Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
| | - Ganwu Li
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | | | - Karsten Tedin
- Institute for Microbiology and Epizootics, Free University of Berlin, Berlin, Germany
| | - Dirk Roggenbuck
- Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
- Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus-Senftenberg, the Brandenburg Medical School Theodor Fontane and the University of Potsdam, Potsdam, Germany
| | - Peter Schierack
- Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
- Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus-Senftenberg, the Brandenburg Medical School Theodor Fontane and the University of Potsdam, Potsdam, Germany
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Escherichia coli O157:H7 Curli Fimbriae Promotes Biofilm Formation, Epithelial Cell Invasion, and Persistence in Cattle. Microorganisms 2020; 8:microorganisms8040580. [PMID: 32316415 PMCID: PMC7232329 DOI: 10.3390/microorganisms8040580] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/15/2020] [Indexed: 02/08/2023] Open
Abstract
Escherichia coli O157:H7 (O157) is noninvasive and a weak biofilm producer; however, a subset of O157 are exceptions. O157 ATCC 43895 forms biofilms and invades epithelial cells. Tn5 mutagenesis identified a mutation responsible for both phenotypes. The insertion mapped within the curli csgB fimbriae locus. Screening of O157 strains for biofilm formation and cell invasion identified a bovine and a clinical isolate with those characteristics. A single base pair A to T transversion, intergenic to the curli divergent operons csgDEFG and csgBAC, was present only in biofilm-producing and invasive strains. Using site-directed mutagenesis, this single base change was introduced into two curli-negative/noninvasive O157 strains and modified strains to form biofilms, produce curli, and gain invasive capability. Transmission electron microscopy (EM) and immuno-EM confirmed curli fibers. EM of bovine epithelial cells (MAC-T) co-cultured with curli-expressing O157 showed intracellular bacteria. The role of curli in O157 persistence in cattle was examined by challenging cattle with curli-positive and -negative O157 and comparing carriage. The duration of bovine colonization with the O157 curli-negative mutant was shorter than its curli-positive isogenic parent. These findings definitively demonstrate that a single base pair stably confers biofilm formation, epithelial cell invasion, and persistence in cattle.
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Jin X, Lee YJ, Hong SH. Canavalia ensiformis-derived lectin inhibits biofilm formation of enterohemorrhagic Escherichia coli and Listeria monocytogenes. J Appl Microbiol 2018; 126:300-310. [PMID: 30240117 DOI: 10.1111/jam.14108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 09/02/2018] [Accepted: 09/10/2018] [Indexed: 12/18/2022]
Abstract
AIM A lectin Concanavalin A (ConA) derived from Canavalia ensiformis (jack bean) exhibits high-binding affinity to carbohydrates on bacterial cell surfaces. The objective of this study was to inhibit the biofilm formation of the foodborne pathogens enterohemorrhagic Escherichia coli and Listeria monocytogenes using ConA prepared by a membrane-based extraction method. METHODS AND RESULTS ConA was extracted using a simple and inexpensive membrane method instead of a chromatography approach. The extracted ConA was effective in inhibiting biofilms of E. coli by 30-fold and L. monocytogenes by 140-fold. In addition, ConA decreased the swimming motility of enterohemorrhagic E. coli EDL933 (EHEC) by 37%, resulting in low biofilm formation, as ConA binding to the bacterial cell surfaces might cause a reduced capability to adhere due to low cellular motility. We confirmed that the extracted ConA contains active components at less than 10 kDa as well as ConA multimers (>30 kDa) that repress EHEC biofilms. Additionally, noncell-based mannose reduced the activity of ConA in inhibiting biofilms. CONCLUSIONS ConA extracted using the membrane-based method is active in inhibiting the biofilm formation by E. coli and L. monocytogenes via the mannose-binding affinity of ConA. SIGNIFICANCE AND IMPACT OF THE STUDY ConA can be used as a promising anti-adherent and antibiofilm agent in inhibiting biofilm formation by enterohemorrhagic E. coli and L. monocytogenes. The membrane-based extraction approach may be applied for the economic production of biologically active lectins.
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Affiliation(s)
- X Jin
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Y J Lee
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA
| | - S H Hong
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, USA
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Sharma VK, Schaut RG, Loving CL. Vaccination with killed whole-cells of Escherichia coli O157:H7 hha mutant emulsified with an adjuvant induced vaccine strain-specific serum antibodies and reduced E. coli O157:H7 fecal shedding in cattle. Vet Microbiol 2018; 219:190-199. [PMID: 29778196 DOI: 10.1016/j.vetmic.2018.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 03/30/2018] [Accepted: 04/03/2018] [Indexed: 01/15/2023]
Abstract
Escherichia coli O157:H7 (O157) can cause from a mild diarrheal illness to hemorrhagic colitis and hemolytic uremic syndrome in humans. Cattle are the primary reservoir for O157 and fecal shedding of O157 by these animals is a major risk factor in contamination of cattle hides and carcasses at slaughter. Vaccination is an important strategy to reduce fecal shedding of O157 in cattle. In this study, we evaluated the immunogenicity and efficacy of an inactivated vaccine strain of O157 formulated with an adjuvant. This vaccine strain was deleted of the hha gene enabling high level expression of the locus of enterocyte effacement (LEE) encoded proteins required for O157 colonization in cattle. The inactivated vaccine strain emulsified with the adjuvant or suspended in the phosphate-buffered saline (PBS) was injected in the neck muscles of two groups of weaned calves followed by a booster three weeks later with the corresponding formulation. Animals in groups 3 and 4 were injected similarly with the adjuvant and PBS, respectively. All animals were orally inoculated three weeks post-booster vaccination with a live culture of O157. The animals vaccinated with the adjuvanted vaccine showed higher serum antibody titers to the vaccine strain and shed O157 for a shorter duration and at lower numbers compared to the animals vaccinated with the non-adjuvanted vaccine, adjuvant-only, or PBS. Western blotting of the vaccine strain lysates showed higher immunoreactivity of serum IgG in vaccinated animals to several O157-specific proteins and lipopolysaccharides (LPS). The vaccination induced IgG showed specificity to LEE-encoded proteins and outer membrane LPS as LEE and waaL deletion mutants, unable to produce LEE proteins and synthesize high molecular weight LPS, respectively, yielded significantly lower antibody titers compared to the parent vaccine strain. The positive reactivity of the immune serum was also observed for purified LEE-encoded proteins EspA and EspB. In conclusion, the results of this animal study showed that a two-dose regimen of an adjuvanted vaccine is capable of inducing O157-specific immune response that directly or indirectly reduced fecal shedding of O157 in cattle.
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Affiliation(s)
- Vijay K Sharma
- USDA, ARS, National Animal Disease Center, Food Safety and Enteric Pathogens Research Unit, Ames, IA, 50010, USA.
| | - Robert G Schaut
- Oak Ridge Institute for Science and Education (ORISE)/ARS Research Participation Program, Oak Ridge, TN 37831
| | - Crystal L Loving
- USDA, ARS, National Animal Disease Center, Food Safety and Enteric Pathogens Research Unit, Ames, IA, 50010, USA
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O’Donoghue EJ, Sirisaengtaksin N, Browning DF, Bielska E, Hadis M, Fernandez-Trillo F, Alderwick L, Jabbari S, Krachler AM. Lipopolysaccharide structure impacts the entry kinetics of bacterial outer membrane vesicles into host cells. PLoS Pathog 2017; 13:e1006760. [PMID: 29186191 PMCID: PMC5724897 DOI: 10.1371/journal.ppat.1006760] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 12/11/2017] [Accepted: 11/17/2017] [Indexed: 11/19/2022] Open
Abstract
Outer membrane vesicles are nano-sized microvesicles shed from the outer membrane of Gram-negative bacteria and play important roles in immune priming and disease pathogenesis. However, our current mechanistic understanding of vesicle-host cell interactions is limited by a lack of methods to study the rapid kinetics of vesicle entry and cargo delivery to host cells. Here, we describe a highly sensitive method to study the kinetics of vesicle entry into host cells in real-time using a genetically encoded, vesicle-targeted probe. We found that the route of vesicular uptake, and thus entry kinetics and efficiency, are shaped by bacterial cell wall composition. The presence of lipopolysaccharide O antigen enables vesicles to bypass clathrin-mediated endocytosis, which enhances both their entry rate and efficiency into host cells. Collectively, our findings highlight the composition of the bacterial cell wall as a major determinant of secretion-independent delivery of virulence factors during Gram-negative infections.
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Affiliation(s)
- Eloise J. O’Donoghue
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Natalie Sirisaengtaksin
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, Texas, United States of America
| | - Douglas F. Browning
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Ewa Bielska
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Mohammed Hadis
- Institute of Microbiology and Infection, School of Chemistry, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Francisco Fernandez-Trillo
- Institute of Microbiology and Infection, School of Chemistry, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Luke Alderwick
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Sara Jabbari
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston, Houston, Texas, United States of America
- * E-mail:
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Xie F, Li G, Wang Y, Zhang Y, Zhou L, Wang C, Liu S, Liu S, Wang C. Pyridoxal phosphate synthases PdxS/PdxT are required for Actinobacillus pleuropneumoniae viability, stress tolerance and virulence. PLoS One 2017; 12:e0176374. [PMID: 28448619 PMCID: PMC5407770 DOI: 10.1371/journal.pone.0176374] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 04/10/2017] [Indexed: 11/29/2022] Open
Abstract
Pyridoxal 5’-phosphate (PLP) is an essential cofactor for numerous enzymes involved in a diversity of cellular processes in living organisms. Previous analysis of the Actinobacillus pleuropneumoniae S-8 genome sequence revealed the presence of pdxS and pdxT genes, which are implicated in deoxyxylulose 5-phosphate (DXP)-independent pathway of PLP biosynthesis; however, little is known about their roles in A. pleuropneumoniae pathogenicity. Our data demonstrated that A. pleuropneumoniae could synthesize PLP by PdxS and PdxT enzymes. Disruption of the pdxS and pdxT genes rendered the pathogen auxotrophic for PLP, and the defective growth as a result of these mutants was chemically compensated by the addition of PLP, suggesting the importance of PLP production for A. pleuropneumoniae growth and viability. Additionally, the pdxS and pdxT deletion mutants displayed morphological defects as indicated by irregular and aberrant shapes in the absence of PLP. The reduced growth of the pdxS and pdxT deletion mutants under osmotic and oxidative stress conditions suggests that the PLP synthases PdxS/PdxT are associated with the stress tolerance of A. pleuropneumoniae. Furthermore, disruption of the PLP biosynthesis pathway led to reduced colonization and attenuated virulence of A. pleuropneumoniae in the BALB/c mouse model. The data presented in this study reveal the critical role of PLP synthases PdxS/PdxT in viability, stress tolerance, and virulence of A. pleuropneumoniae.
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Affiliation(s)
- Fang Xie
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Gang Li
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Yalei Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Yanhe Zhang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Long Zhou
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Chengcheng Wang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Shuanghong Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Chunlai Wang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
- * E-mail:
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12
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Kuo CJ, Chen JW, Chiu HC, Teng CH, Hsu TI, Lu PJ, Syu WJ, Wang ST, Chou TC, Chen CS. Mutation of the Enterohemorrhagic Escherichia coli Core LPS Biosynthesis Enzyme RfaD Confers Hypersusceptibility to Host Intestinal Innate Immunity In vivo. Front Cell Infect Microbiol 2016; 6:82. [PMID: 27570746 PMCID: PMC4982379 DOI: 10.3389/fcimb.2016.00082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/02/2016] [Indexed: 11/13/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important foodborne pathogen causing severe diseases in humans worldwide. Currently, there is no specific treatment available for EHEC infection and the use of conventional antibiotics is contraindicated. Therefore, identification of potential therapeutic targets and development of effective measures to control and treat EHEC infection are needed. Lipopolysaccharides (LPS) are surface glycolipids found on the outer membrane of gram-negative bacteria, including EHEC, and LPS biosynthesis has long been considered as potential anti-bacterial target. Here, we demonstrated that the EHEC rfaD gene that functions in the biosynthesis of the LPS inner core is required for the intestinal colonization and pathogenesis of EHEC in vivo. Disruption of the EHEC rfaD confers attenuated toxicity in Caenorhabditis elegans and less bacterial colonization in the intestine of C. elegans and mouse. Moreover, rfaD is also involved in the control of susceptibility of EHEC to antimicrobial peptides and host intestinal immunity. It is worth noting that rfaD mutation did not interfere with the growth kinetics when compared to the wild-type EHEC cells. Taken together, we demonstrated that mutations of the EHEC rfaD confer hypersusceptibility to host intestinal innate immunity in vivo, and suggested that targeting the RfaD or the core LPS synthesis pathway may provide alternative therapeutic regimens for EHEC infection.
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Affiliation(s)
- Cheng-Ju Kuo
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Jenn-Wei Chen
- Center of Infectious Disease and Signaling Research, National Cheng Kung UniversityTainan, Taiwan
| | - Hao-Chieh Chiu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan UniversityTaipei, Taiwan
| | - Ching-Hao Teng
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Tai-I Hsu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Pei-Jung Lu
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Wan-Jr Syu
- Institute of Microbiology and Immunology, National Yang Ming UniversityTaipei, Taiwan
| | - Sin-Tian Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Ting-Chen Chou
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Chang-Shi Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
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13
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Al-Maleki AR, Mariappan V, Vellasamy KM, Tay ST, Vadivelu J. Altered Proteome of Burkholderia pseudomallei Colony Variants Induced by Exposure to Human Lung Epithelial Cells. PLoS One 2015; 10:e0127398. [PMID: 25996927 PMCID: PMC4440636 DOI: 10.1371/journal.pone.0127398] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 04/14/2015] [Indexed: 12/19/2022] Open
Abstract
Burkholderia pseudomallei primary diagnostic cultures demonstrate colony morphology variation associated with expression of virulence and adaptation proteins. This study aims to examine the ability of B. pseudomallei colony variants (wild type [WT] and small colony variant [SCV]) to survive and replicate intracellularly in A549 cells and to identify the alterations in the protein expression of these variants, post-exposure to the A549 cells. Intracellular survival and cytotoxicity assays were performed followed by proteomics analysis using two-dimensional gel electrophoresis. B. pseudomallei SCV survive longer than the WT. During post-exposure, among 259 and 260 protein spots of SCV and WT, respectively, 19 were differentially expressed. Among SCV post-exposure up-regulated proteins, glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase (CbbA) and betaine aldehyde dehydrogenase were associated with adhesion and virulence. Among the down-regulated proteins, enolase (Eno) is implicated in adhesion and virulence. Additionally, post-exposure expression profiles of both variants were compared with pre-exposure. In WT pre- vs post-exposure, 36 proteins were differentially expressed. Of the up-regulated proteins, translocator protein, Eno, nucleoside diphosphate kinase (Ndk), ferritin Dps-family DNA binding protein and peptidyl-prolyl cis-trans isomerase B were implicated in invasion and virulence. In SCV pre- vs post-exposure, 27 proteins were differentially expressed. Among the up-regulated proteins, flagellin, Eno, CbbA, Ndk and phenylacetate-coenzyme A ligase have similarly been implicated in adhesion, invasion. Protein profiles differences post-exposure provide insights into association between morphotypic and phenotypic characteristics of colony variants, strengthening the role of B. pseudomallei morphotypes in pathogenesis of melioidosis.
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Affiliation(s)
- Anis Rageh Al-Maleki
- Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kumutha Malar Vellasamy
- Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sun Tee Tay
- Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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14
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Rasmussen JA, Fletcher JR, Long ME, Allen LAH, Jones BD. Characterization of Francisella tularensis Schu S4 mutants identified from a transposon library screened for O-antigen and capsule deficiencies. Front Microbiol 2015; 6:338. [PMID: 25999917 PMCID: PMC4419852 DOI: 10.3389/fmicb.2015.00338] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/06/2015] [Indexed: 02/02/2023] Open
Abstract
The lipopolysaccharide (LPS) and O-antigen polysaccharide capsule structures of Francisella tularensis play significant roles in helping these highly virulent bacteria avoid detection within a host. We previously created pools of F. tularensis mutants that we screened to identify strains that were not reactive to a monoclonal antibody to the O-antigen capsule. To follow up previously published work, we characterize further seven of the F. tularensis Schu S4 mutant strains identified by our screen. These F. tularensis strains carry the following transposon mutations: FTT0846::Tn5, hemH::Tn5, wbtA::Tn5, wzy::Tn5, FTT0673p/prsA::Tn5, manB::Tn5, or dnaJ::Tn5. Each of these strains displayed sensitivity to human serum, to varying degrees, when compared to wild-type F. tularensis Schu S4. By Western blot, only FTT0846::Tn5, wbtA::Tn5, wzy::Tn5, and manB::Tn5 strains did not react to the capsule and LPS O-antigen antibody 11B7, although the wzy::Tn5 strain did have a single O-antigen reactive band that was detected by the FB11 monoclonal antibody. Of these strains, manB::Tn5 and FTT0846 appear to have LPS core truncations, whereas wbtA::Tn5 and wzy::Tn5 had LPS core structures that are similar to the parent F. tularensis Schu S4. These strains were also shown to have poor growth within human monocyte derived macrophages (MDMs) and bone marrow derived macrophages (BMDMs). We examined the virulence of these strains in mice, following intranasal challenge, and found that each was attenuated compared to wild type Schu S4. Our results provide additional strong evidence that LPS and/or capsule are F. tularensis virulence factors that most likely function by providing a stealth shield that prevents the host immune system from detecting this potent pathogen.
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Affiliation(s)
- Jed A Rasmussen
- Department of Microbiology, University of Iowa Carver College of Medicine Iowa City, IA, USA
| | - Joshua R Fletcher
- Genetics Program, University of Iowa Carver College of Medicine Iowa City, IA, USA
| | - Matthew E Long
- Molecular and Cellular Biology Program, University of Iowa Carver College of Medicine Iowa City, IA, USA
| | - Lee-Ann H Allen
- Department of Microbiology, University of Iowa Carver College of Medicine Iowa City, IA, USA ; Molecular and Cellular Biology Program, University of Iowa Carver College of Medicine Iowa City, IA, USA ; Department of Internal Medicine, University of Iowa Carver College of Medicine Iowa City, IA, USA
| | - Bradley D Jones
- Department of Microbiology, University of Iowa Carver College of Medicine Iowa City, IA, USA ; Genetics Program, University of Iowa Carver College of Medicine Iowa City, IA, USA
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15
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Baccus-Taylor GSH, Falloon OC, Henry N. Pressure resistance of cold-shocked Escherichia coli O157:H7 in ground beef, beef gravy and peptone water. J Appl Microbiol 2015; 118:1521-9. [PMID: 25766637 DOI: 10.1111/jam.12794] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/27/2015] [Accepted: 03/10/2015] [Indexed: 01/06/2023]
Abstract
AIMS (i) To study the effects of cold shock on Escherichia coli O157:H7 cells. (ii) To determine if cold-shocked E. coli O157:H7 cells at stationary and exponential phases are more pressure-resistant than their non-cold-shocked counterparts. (iii) To investigate the baro-protective role of growth media (0·1% peptone water, beef gravy and ground beef). METHODS AND RESULTS Quantitative estimates of lethality and sublethal injury were made using the differential plating method. There were no significant differences (P > 0·05) in the number of cells killed; cold-shocked or non-cold-shocked. Cells grown in ground beef (stationary and exponential phases) experienced lowest death compared with peptone water and beef gravy. Cold-shock treatment increased the sublethal injury to cells cultured in peptone water (stationary and exponential phases) and ground beef (exponential phase), but decreased the sublethal injury to cells in beef gravy (stationary phase). CONCLUSIONS Cold shock did not confer greater resistance to stationary or exponential phase cells pressurized in peptone water, beef gravy or ground beef. Ground beef had the greatest baro-protective effect. SIGNIFICANCE AND IMPACT OF THE STUDY Real food systems should be used in establishing food safety parameters for high-pressure treatments; micro-organisms are less resistant in model food systems, the use of which may underestimate the organisms' resistance.
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Affiliation(s)
- G S H Baccus-Taylor
- Food Science and Technology Unit, Department of Chemical Engineering, The University of the West Indies, St Augustine, Trinidad and Tobago, West Indies
| | - O C Falloon
- Food Science and Technology Unit, Department of Chemical Engineering, The University of the West Indies, St Augustine, Trinidad and Tobago, West Indies
| | - N Henry
- Food Science and Technology Unit, Department of Chemical Engineering, The University of the West Indies, St Augustine, Trinidad and Tobago, West Indies
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16
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Lu Z, Breidt F. Escherichia coli O157:H7 bacteriophage Φ241 isolated from an industrial cucumber fermentation at high acidity and salinity. Front Microbiol 2015; 6:67. [PMID: 25741324 PMCID: PMC4330901 DOI: 10.3389/fmicb.2015.00067] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/20/2015] [Indexed: 12/16/2022] Open
Abstract
A novel phage, Φ241, specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH ≤ 3.7) and salinity (≥5% NaCl) were high. The phage belongs to the Myoviridae family. Its latent period was 15 min and average burst size was 53 phage particles per infected cell. The phage was able to lyse 48 E. coli O157:H7 strains, but none of the 18 non-O157 strains (including E. coli O104:H7) or the 2 O antigen-negative mutants of O157:H7 strain, 43895Δper (also lacking H7 antigen) and F12 (still expressing H7 antigen). However, the phage was able to lyse a per-complemented strain (43895ΔperComp) which expresses O157 antigen. These results indicated that phage Φ241 is specific for O157 antigen, and E. coli strains lacking O157 antigen were resistant to the phage infection, regardless of the presence or absence of H7 antigen. SDS-PAGE profile revealed at least 13 structural proteins of the phage. The phage DNA was resistant to many commonly used restriction endonucleases, suggesting the presence of modified nucleotides in the phage genome. At the multiplicity of infection of 10, 3, or 0.3, the phage caused a rapid cell lysis within 1 or 2 h, resulting in 3.5- or 4.5-log-unit reduction in cell concentration. The high lytic activity, specificity and tolerance to low pH and high salinity make phage Φ241 a potentially ideal biocontrol agent of E. coli O157:H7 in various foods. To our knowledge, this is the first report on E. coli O157:H7 phage isolated from high acidity and salinity environment.
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Affiliation(s)
- Zhongjing Lu
- Department of Molecular and Cellular Biology, Kennesaw State UniversityKennesaw, GA, USA
| | - Fred Breidt
- USDA Agricultural Research Service – Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State UniversityRaleigh, NC, USA
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17
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Cote R, Katani R, Moreau MR, Kudva IT, Arthur TM, DebRoy C, Mwangi MM, Albert I, Raygoza Garay JA, Li L, Brandl MT, Carter MQ, Kapur V. Comparative analysis of super-shedder strains of Escherichia coli O157:H7 reveals distinctive genomic features and a strongly aggregative adherent phenotype on bovine rectoanal junction squamous epithelial cells. PLoS One 2015; 10:e0116743. [PMID: 25664460 PMCID: PMC4321836 DOI: 10.1371/journal.pone.0116743] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 12/12/2014] [Indexed: 12/13/2022] Open
Abstract
Shiga toxin-producing Escherichia coli O157:H7 (O157) are significant foodborne pathogens and pose a serious threat to public health worldwide. The major reservoirs of O157 are asymptomatic cattle which harbor the organism in the terminal recto-anal junction (RAJ). Some colonized animals, referred to as “super-shedders” (SS), are known to shed O157 in exceptionally large numbers (>104 CFU/g of feces). Recent studies suggest that SS cattle play a major role in the prevalence and transmission of O157, but little is known about the molecular mechanisms associated with super-shedding. Whole genome sequence analysis of an SS O157 strain (SS17) revealed a genome of 5,523,849 bp chromosome with 5,430 open reading frames and two plasmids, pO157 and pSS17, of 94,645 bp and 37,446 bp, respectively. Comparative analyses showed that SS17 is clustered with spinach-associated O157 outbreak strains, and belongs to the lineage I/II, clade 8, D group, and genotype 1, a subgroup of O157 with predicted hyper-virulence. A large number of non-synonymous SNPs and other polymorphisms were identified in SS17 as compared with other O157 strains (EC4115, EDL933, Sakai, TW14359), including in key adherence- and virulence-related loci. Phenotypic analyses revealed a distinctive and strongly adherent aggregative phenotype of SS17 on bovine RAJ stratified squamous epithelial (RSE) cells that was conserved amongst other SS isolates. Molecular genetic and functional analyses of defined mutants of SS17 suggested that the strongly adherent aggregative phenotype amongst SS isolates is LEE-independent, and likely results from a novel mechanism. Taken together, our study provides a rational framework for investigating the molecular mechanisms associated with SS, and strong evidence that SS O157 isolates have distinctive features and use a LEE-independent mechanism for hyper-adherence to bovine rectal epithelial cells.
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Affiliation(s)
- Rebecca Cote
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Robab Katani
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Matthew R. Moreau
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Indira T. Kudva
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, Iowa, United States of America
| | - Terrance M. Arthur
- Roman L. Hruska U.S. Meat Animal Research Center, Agricultural Research Service, U.S. Department of Agriculture, Clay Center, Nebraska, United States of America
| | - Chitrita DebRoy
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- E. coli Reference Center, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Michael M. Mwangi
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Istvan Albert
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Juan Antonio Raygoza Garay
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Lingling Li
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Maria T. Brandl
- Produce Safety and Microbiology, Research Unit, Agriculture Research Service, U.S. Department of Agriculture, Albany, California, United States of America
| | - Michelle Q. Carter
- Produce Safety and Microbiology, Research Unit, Agriculture Research Service, U.S. Department of Agriculture, Albany, California, United States of America
| | - Vivek Kapur
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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18
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Elhadidy M, Mohammed M. Interaction of Different Shiga Toxin–ProducingEscherichia coliSerotypes with Caco-2 Cells. Foodborne Pathog Dis 2014; 11:874-80. [DOI: 10.1089/fpd.2014.1780] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mohamed Elhadidy
- Department of Bacteriology, Mycology, and Immunology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Mahmoud Mohammed
- Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
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19
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Wang S, Czuchry D, Liu B, Vinnikova AN, Gao Y, Vlahakis JZ, Szarek WA, Wang L, Feng L, Brockhausen I. Characterization of two UDP-Gal:GalNAc-diphosphate-lipid β1,3-galactosyltransferases WbwC from Escherichia coli serotypes O104 and O5. J Bacteriol 2014; 196:3122-33. [PMID: 24957618 PMCID: PMC4135647 DOI: 10.1128/jb.01698-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/12/2014] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli displays O antigens on the outer membrane that play an important role in bacterial interactions with the environment. The O antigens of enterohemorrhagic E. coli O104 and O5 contain a Galβ1-3GalNAc disaccharide at the reducing end of the repeating unit. Several other O antigens contain this disaccharide, which is identical to the mammalian O-glycan core 1 or the cancer-associated Thomsen-Friedenreich (TF) antigen. We identified the wbwC genes responsible for the synthesis of the disaccharide in E. coli serotypes O104 and O5. To functionally characterize WbwC, an acceptor substrate analog, GalNAcα-diphosphate-phenylundecyl, was synthesized. WbwC reaction products were isolated by high-pressure liquid chromatography and analyzed by mass spectrometry, nuclear magnetic resonance, galactosidase and O-glycanase digestion, and anti-TF antibody. The results clearly showed that the Galβ1-3GalNAcα linkage was synthesized, confirming WbwCECO104 and WbwCECO5 as UDP-Gal:GalNAcα-diphosphate-lipid β1,3-Gal-transferases. Sequence analysis revealed a conserved DxDD motif, and mutagenesis showed the importance of these Asp residues in catalysis. The purified enzymes require divalent cations (Mn(2+)) for activity and are specific for UDP-Gal and GalNAc-diphosphate lipid substrates. WbwC was inhibited by bis-imidazolium salts having aliphatic chains of 18 to 22 carbons. This work will help to elucidate mechanisms of polysaccharide synthesis in pathogenic bacteria and provide technology for vaccine synthesis.
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Affiliation(s)
- Shuo Wang
- Department of Medicine and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Diana Czuchry
- Department of Medicine and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Bin Liu
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Anna N Vinnikova
- Department of Medicine and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Yin Gao
- Department of Medicine and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Jason Z Vlahakis
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada
| | - Walter A Szarek
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada
| | - Lei Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Lu Feng
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Inka Brockhausen
- Department of Medicine and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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20
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A mutation in rcsB, a gene encoding the core component of the Rcs cascade, enhances the virulence of Edwardsiella tarda. Res Microbiol 2014; 165:226-32. [PMID: 24631591 DOI: 10.1016/j.resmic.2014.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 02/27/2014] [Indexed: 12/22/2022]
Abstract
Edwardsiella tarda, a Gram-negative bacterium of the family Enterobacteriaceae, is the causative agent of the systemic disease edwardsiellosis, which is a major problem in aquaculture industry worldwide. Many virulence-related genes in E. tarda have been investigated, but the Rcs phosphorelay, a two-component pathway, which regulates several cell-surface-associated structures related to invasion and survival in host cells, has not yet been thoroughly studied. In the present study, an rcsB in-frame deletion mutant ΔrcsB was constructed through double-crossover allelic exchange. To complement the rcsB mutation, the ΔrcsB (pACYC184K-rcsB) mutant was constructed by transformation of a low-copy plasmid carrying the intact rcsB into the ΔrcsB mutant of E. tarda. Several virulence-associated characters of the mutants and wild-type strain were tested. Compared with wild-type strain EIB202, biofilm formation decreased significantly in ΔrcsB, while ΔrcsB (pACYC184K-rcsB) recovered the phenotype to some extent. In addition, the capacity for autoagglutination, the percentage of adherence and internalization to Epithelioma papulosum cyprini cells and lethality toward zebrafish embryos significantly increased in ΔrcsB. All these phenomena displayed by mutant ΔrcsB showed a certain degree of recovery, though incomplete, in strain ΔrcsB (pACYC184K-rcsB). Present results indicate that rcsB is involved in regulating the gene expression of virulence factors in E. tarda, as shown in other members of Enterobacteriaceae.
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21
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Isolation of Escherichia coli 0157:H7 strain from fecal samples of zoo animal. ScientificWorldJournal 2013; 2013:843968. [PMID: 24489514 PMCID: PMC3893011 DOI: 10.1155/2013/843968] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 09/29/2013] [Indexed: 11/21/2022] Open
Abstract
The isolation and characterization of Escherichia coli O157:H7 strains from 22 out of 174 fecal samples from petting zoo animals representing twenty-two different species (camel, lion, goats, zebra, bear, baboon monkey, Siberian monkey, deer, elk, llama, pony, horses, fox, kangaroo, wolf, porcupine, chickens, tiger, ostrich, hyena, dogs, and wildcats) were investigated. One petting Al-Zawraa zoological society of Baghdad was investigated for E. coli O157:H7 over a 16-month period that spanned two summer and two autumn seasons. Variation in the occurrence of E. coli O157:H7-positive petting zoo animals was observed, with animals being culture positive only in the summer months but not in the spring, autumn, or winter. E. coli O157:H7 isolates were distinguished by agglutination with E. coli O157:H7 latex reagent (Oxoid), identified among the isolates, which showed that multiple E. coli strains were isolated from one petting zoo animal, in which a single animal simultaneously shed multiple E. coli strains; E. coli O157:H7 was isolated only by selective enrichment culture of 2 g of petting zoo animal feces. In contrast, strains other than O157:H7 were cultured from feces of petting zoo animals without enrichment.
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Escherichia coli O157:H7 LPS O-side chains and pO157 are required for killing Caenorhabditis elegans. Biochem Biophys Res Commun 2013; 436:388-93. [DOI: 10.1016/j.bbrc.2013.05.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 05/27/2013] [Indexed: 01/13/2023]
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Visvalingam J, Hernandez-Doria JD, Holley RA. Examination of the genome-wide transcriptional response of Escherichia coli O157:H7 to cinnamaldehyde exposure. Appl Environ Microbiol 2013; 79:942-50. [PMID: 23183978 PMCID: PMC3568558 DOI: 10.1128/aem.02767-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/20/2012] [Indexed: 02/06/2023] Open
Abstract
Cinnamaldehyde is a natural antimicrobial that has been found to be effective against many food-borne pathogens, including Escherichia coli O157:H7. Although its antimicrobial effects have been well investigated, limited information is available on its effects at the molecular level. Sublethal treatment at 200 mg/liter cinnamaldehyde inhibited growth of E. coli O157:H7 at 37°C and for ≤2 h caused cell elongation, but from 2 to 4 h growth resumed and cells reverted to normal length. To understand this transient behavior, genome-wide transcriptional analysis of E. coli O157:H7 was performed at 2 and 4 h of exposure to cinnamaldehyde in conjunction with reverse-phase high-performance liquid chromatography (RP-HPLC) analysis for cinnamaldehyde and other cinnamic compounds. Drastically different gene expression profiles were obtained at 2 and 4 h. RP-HPLC analysis showed that cinnamaldehyde was structurally stable for at least 2 h. At 2 h of exposure, cinnamaldehyde induced expression of many oxidative stress-related genes and repressed expression of DNA, protein, O-antigen, and fimbrial synthetic genes. At 4 h, many cinnamaldehyde-induced repressive effects on E. coli O157:H7 gene expression were reversed, and cells became more motile and grew at a slightly higher rate. Data indicated that by 4 h, E. coli O157:H7 was able to convert cinnamaldehyde into the less toxic cinnamic alcohol using dehydrogenase/reductase enzymes (YqhD and DkgA). This is the first study to characterize the ability of E. coli O157:H7 to convert cinnamaldehyde into cinnamic alcohol which, in turn, showed that the antimicrobial activity of cinnamaldehyde is mainly attributable to its carbonyl aldehyde group.
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Affiliation(s)
| | | | - Richard A. Holley
- Department of Food Science, University of Manitoba, Winnipeg, Manitoba, Canada
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Gao Y, Vinnikova A, Brockhausen I. Functional identification of bacterial glucosyltransferase WbdN. Methods Mol Biol 2013; 1022:199-214. [PMID: 23765664 DOI: 10.1007/978-1-62703-465-4_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The outer membrane of gram-negative bacteria is stabilized by lipopolysaccharides (LPS). The O-antigenic polysaccharides of LPS are composed of repeating units that are exposed to and can interact with the environment. The glycosyltransferases that assemble these repeating units are encoded by the O-antigen gene cluster and utilize undecaprenol-phosphate-linked intermediates as natural acceptor substrates, and nucleotide sugars as donor substrates on the cytoplasmic face of the inner membrane. Many of the glycosyltransferase genes are known but the enzymatic functions of most of them remain to be identified. We describe here how the function of a recombinant glucosyltransferase WbdN from Escherichia coli O157 can be determined by NMR analysis of the enzyme product, using a synthetic acceptor substrate analog. A fluorescent acceptor substrate analog can be used in highly sensitive enzyme assays that allow the characterization of enzyme activity without the use of radioactive nucleotide sugar donor substrates.
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Affiliation(s)
- Yin Gao
- Department of Medicine, Division of Rheumatology, Queen's University, Kingston, Ontario, Canada
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25
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Synthesis of a fluorescent acceptor substrate for glycosyltransferases involved in the assembly of O-antigens of enterohemorrhagic Escherichia coli O157 and O5. Carbohydr Res 2013; 366:17-24. [DOI: 10.1016/j.carres.2012.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 11/13/2012] [Accepted: 11/15/2012] [Indexed: 11/23/2022]
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26
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Bertin Y, Chaucheyras-Durand F, Robbe-Masselot C, Durand A, de la Foye A, Harel J, Cohen PS, Conway T, Forano E, Martin C. Carbohydrate utilization by enterohaemorrhagic Escherichia coli O157:H7 in bovine intestinal content. Environ Microbiol 2012; 15:610-22. [PMID: 23126484 DOI: 10.1111/1462-2920.12019] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 10/01/2012] [Accepted: 10/02/2012] [Indexed: 12/16/2022]
Abstract
The bovine gastrointestinal (GI) tract is the main reservoir for enterohaemorrhagic Escherichia coli (EHEC) responsible for food-borne infections. Characterization of nutrients preferentially used by EHEC in the bovine intestine would help to develop ecological strategies to reduce EHEC carriage. However, the carbon sources that support the growth of EHEC in the bovine intestine are poorly documented. In this study, a very low concentration of glucose, the most abundant monomer included in the cattle dietary polysaccharides, was detected in bovine small intestine contents (BSIC) collected from healthy cows at the slaughterhouse. Six carbohydrates reported to be included in the mucus layer covering the enterocytes [galactose, N-acetyl-glucosamine (GlcNAc), N-acetyl- galactosamine (GalNAc), fucose, mannose and N-acetyl neuraminic acid (Neu5Ac)] have been quantified for the first time in BSIC and accounted for a total concentration of 4.2 mM carbohydrates. The genes required for enzymatic degradation of the six mucus-derived carbohydrates are highly expressed during the exponential growth of the EHEC strain O157:H7 EDL933 in BSIC and are more strongly induced in EHEC than in bovine commensal E. coli. In addition, EDL933 consumed the free monosaccharides present in the BSIC more rapidly than the resident microbiota and commensal E. coli, indicating a competitive ability of EHEC to catabolize mucus-derived carbohydrates in the bovine gut. Mutations of EDL933 genes required for the catabolism of each of these sugars have been constructed, and growth competitions of the mutants with the wild-type strain clearly demonstrated that mannose, GlcNAc, Neu5Ac and galactose catabolism confers a high competitive growth advantage to EHEC in BSIC and probably represents an ecological niche for EHEC strains in the bovine small intestine. The utilization of these mucus-derived monosaccharides by EDL933 is apparently required for rapid growth of EHEC in BSIC, and for maintaining a competitive growth rate as compared with that of commensal E. coli. The results suggest a strategy for O157:H7 E. coli survival in the bovine intestine, whereby EHEC rapidly consumes mucus-derived carbohydrates that are poorly consumed by bacteria belonging to the resident intestinal microbiota, including commensal E. coli.
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Affiliation(s)
- Yolande Bertin
- INRA, UR454 Microbiologie, 63122, Saint-Genès-Champanelle, France.
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Miyashita A, Iyoda S, Ishii K, Hamamoto H, Sekimizu K, Kaito C. Lipopolysaccharide O-antigen of enterohemorrhagic Escherichia coli O157:H7 is required for killing both insects and mammals. FEMS Microbiol Lett 2012; 333:59-68. [DOI: 10.1111/j.1574-6968.2012.02599.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 05/14/2012] [Indexed: 01/08/2023] Open
Affiliation(s)
- Atsushi Miyashita
- Laboratory of Microbiology; Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo; Bunkyo-ku; Tokyo; Japan
| | - Sunao Iyoda
- Department of Bacteriology; National Institute of Infectious Diseases; Shinjuku-ku; Tokyo; Japan
| | - Kenichi Ishii
- Laboratory of Microbiology; Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo; Bunkyo-ku; Tokyo; Japan
| | - Hiroshi Hamamoto
- Laboratory of Microbiology; Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo; Bunkyo-ku; Tokyo; Japan
| | - Kazuhisa Sekimizu
- Laboratory of Microbiology; Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo; Bunkyo-ku; Tokyo; Japan
| | - Chikara Kaito
- Laboratory of Microbiology; Graduate School of Pharmaceutical Sciences; The University of Tokyo; Hongo; Bunkyo-ku; Tokyo; Japan
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Gao Y, Liu B, Strum S, Schutzbach JS, Druzhinina TN, Utkina NS, Torgov VI, Danilov LL, Veselovsky VV, Vlahakis JZ, Szarek WA, Wang L, Brockhausen I. Biochemical characterization of WbdN, a β1,3-glucosyltransferase involved in O-antigen synthesis in enterohemorrhagic Escherichia coli O157. Glycobiology 2012; 22:1092-102. [PMID: 22556057 DOI: 10.1093/glycob/cws081] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The enterohemorrhagic O157 strain of Escherichia coli, which is one of the most well-known bacterial pathogens, has an O-antigen repeating unit structure with the sequence [-2-d-Rha4NAcα1-3-l-Fucα1-4-d-Glcβ1-3-d-GalNAcα1-]. The O-antigen gene cluster of E. coli O157 contains the genes responsible for the assembly of this repeating unit and includes wbdN. In spite of cloning many O-antigen genes, biochemical characterization has been done on very few enzymes involved in O-antigen synthesis. In this work, we expressed the wbdN gene in E. coli BL21, and the His-tagged protein was purified. WbdN activity was characterized using the donor substrate UDP-[(14)C]Glc and the synthetic acceptor substrate GalNAcα-O-PO(3)-PO(3)-(CH(2))(11)-O-Ph. The enzyme product was isolated by high pressure liquid chromatography, and mass spectrometry showed that one Glc residue was transferred to the acceptor by WbdN. Nuclear magnetic resonance analysis of the product structure indicated that Glc was β1-3 linked to GalNAc. WbdN contains a conserved DxD motif and requires divalent metal ions for full activity. WbdN activity has an optimal pH between 7 and 8 and is highly specific for UDP-Glc as the donor substrate. GalNAcα derivatives lacking the diphosphate group were inactive as substrates, and the enzyme did not transfer Glc to GlcNAcα-O-PO(3)-PO(3)-(CH(2))(11)-O-Ph. Our results illustrate that WbdN is a specific UDP-Glc:GalNAcα-diphosphate-lipid β1,3-Glc-transferase. The enzyme is a target for the development of inhibitors to block O157-antigen synthesis.
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Affiliation(s)
- Yin Gao
- Department of Medicine, Division of Rheumatology, Queen's University, Kingston, Ontario, Canada
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Sharma M, Lakshman S, Ferguson S, Ingram DT, Luo Y, Patel J. Effect of modified atmosphere packaging on the persistence and expression of virulence factors of Escherichia coli O157:H7 on shredded iceberg lettuce. J Food Prot 2011; 74:718-26. [PMID: 21549041 DOI: 10.4315/0362-028x.jfp-10-427] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Fresh-cut leafy greens contaminated with Escherichia coli O157:H7 have caused foodborne outbreaks. Packaging conditions, coupled with abusive storage temperatures of contaminated lettuce, were evaluated for their effect on the potential virulence of E. coli O157:H7. Shredded lettuce was inoculated with 5.58 and 3.98 log CFU E. coli O157:H7 per g and stored at 4 and 15°C, respectively, for up to 10 days. Lettuce was packaged under treatment A (modified atmosphere packaging conditions used for commercial fresh-cut produce, in gas-permeable film with N(2)), treatment B (near-ambient air atmospheric conditions in a gas-permeable film with microperforations), and treatment C (high-CO(2) and low-O(2) conditions in a gas-impermeable film). E. coli O157:H7 populations from each treatment were determined by enumeration of numbers on MacConkey agar containing nalidixic acid. RNA was extracted from packaged lettuce for analysis of expression of virulence factor genes stx(2), eae, ehxA, iha, and rfbE. E. coli O157:H7 populations on lettuce at 4°C under all treatments decreased, but most considerably so under treatment B over 10 days. At 15°C, E. coli O157:H7 populations increased by at least 2.76 log CFU/g under all treatments. At 15°C, expression of eae and iha was significantly greater under treatment B than it was under treatments A and C on day 3. Similarly, treatment B promoted significantly higher expression of stx(2), eae, ehxA, and rfbE genes on day 10, compared with treatments A and C at 15°C. Results indicate that storage under near-ambient air atmospheric conditions can promote higher expression levels of O157 virulence factors on lettuce, and could affect the severity of E. coli O157:H7 infections associated with leafy greens.
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Affiliation(s)
- Manan Sharma
- U.S. Department of Agriculture, Agricultural Research Service, Beltsville Area Research Center, Animal and Natural Resources Institute, Environmental Microbial and Food Safety Laboratory, Building 201, BARC-East, 10300 Baltimore Avenue, Beltsville, Maryland 20705, USA.
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Bazaka K, Jacob MV, Crawford RJ, Ivanova EP. Plasma-assisted surface modification of organic biopolymers to prevent bacterial attachment. Acta Biomater 2011; 7:2015-28. [PMID: 21194574 DOI: 10.1016/j.actbio.2010.12.024] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 12/01/2010] [Accepted: 12/20/2010] [Indexed: 12/30/2022]
Abstract
Despite many synthetic biomaterials having physical properties that are comparable or even superior to those of natural body tissues, they frequently fail due to the adverse physiological reactions they cause within the human body, such as infection and inflammation. The surface modification of biomaterials is an economical and effective method by which biocompatibility and biofunctionality can be achieved while preserving the favorable bulk characteristics of the biomaterial, such as strength and inertness. Amongst the numerous surface modification techniques available, plasma surface modification affords device manufacturers a flexible and environmentally friendly process that enables tailoring of the surface morphology, structure, composition, and properties of the material to a specific need. There are a vast range of possible applications of plasma modification in biomaterial applications, however, the focus of this review paper is on processes that can be used to develop surface morphologies and chemical structures for the prevention of adhesion and proliferation of pathogenic bacteria on the surfaces of in-dwelling medical devices. As such, the fundamental principles of bacterial cell attachment and biofilm formation are also discussed. Functional organic plasma polymerised coatings are also discussed for their potential as biosensitive interfaces, connecting inorganic/metallic electronic devices with their physiological environments.
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Affiliation(s)
- Kateryna Bazaka
- Electronic Materials Research Laboratory, School of Engineering and Physical Sciences, James Cook University, Townsville, Queensland, Australia
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31
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Crhanova M, Malcova M, Mazgajova M, Karasova D, Sebkova A, Fucikova A, Bortlicek Z, Pilousova L, Kyrova K, Dekanova M, Rychlik I. LPS structure influences protein secretion in Salmonella enterica. Vet Microbiol 2011; 152:131-7. [PMID: 21570779 DOI: 10.1016/j.vetmic.2011.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 04/09/2011] [Accepted: 04/14/2011] [Indexed: 12/14/2022]
Abstract
In this study we have compared protein secretion in the wild type of S. Typhimurium and the rfaC mutant. We found out that the rfaC mutant was defective in protein secretion. In addition, the rfaC mutant was defective in its invasion into an IPEC-J2 porcine epithelial cell line and also in motility in semisolid agar. Consistent with this, reduced flagella numbers were observed in the rfaC mutant. In the rfaC mutant, there were no defects in flagellin expression as detected by western blot and immune electron microscopy which demonstrated equal amounts of flagellin in the cytoplasm of both the rfaC mutant and the wild-type S. Typhimurium. However, in the wild-type strain only, the flagellin was assembled to spatially restricted areas on the inner side of cytoplasmic membrane. The oligosaccharide core of LPS is therefore required for the assembly of flagella and T3SS secretion machinery followed by protein secretion.
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Affiliation(s)
- M Crhanova
- Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic
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Eckert SE, Dziva F, Chaudhuri RR, Langridge GC, Turner DJ, Pickard DJ, Maskell DJ, Thomson NR, Stevens MP. Retrospective application of transposon-directed insertion site sequencing to a library of signature-tagged mini-Tn5Km2 mutants of Escherichia coli O157:H7 screened in cattle. J Bacteriol 2011; 193:1771-6. [PMID: 21278291 PMCID: PMC3067669 DOI: 10.1128/jb.01292-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 01/17/2011] [Indexed: 01/27/2023] Open
Abstract
Massively parallel sequencing of transposon-flanking regions assigned the genotype and fitness score to 91% of Escherichia coli O157:H7 mutants previously screened in cattle by signature-tagged mutagenesis (STM). The method obviates the limitations of STM and markedly extended the functional annotation of the prototype E. coli O157:H7 genome without further animal use.
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Affiliation(s)
- Sabine E. Eckert
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Francis Dziva
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Roy R. Chaudhuri
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Gemma C. Langridge
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Daniel J. Turner
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Derek J. Pickard
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Duncan J. Maskell
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Nicholas R. Thomson
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
| | - Mark P. Stevens
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom, Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, United Kingdom, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Bush Farm Road, Roslin, Midlothian EH25 9RG, United Kingdom
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Sheng H, Wang J, Lim JY, Davitt C, Minnich SA, Hovde CJ. Internalization of Escherichia coli o157:h7 by bovine rectal epithelial cells. Front Microbiol 2011; 2:32. [PMID: 21687423 PMCID: PMC3109292 DOI: 10.3389/fmicb.2011.00032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 02/06/2011] [Indexed: 01/06/2023] Open
Abstract
Escherichia coli O157:H7 (O157) causes human diarrheal disease and healthy cattle are its primary reservoir. O157 colonize the bovine epithelial mucosa at the recto-anal junction (RAJ). Previous studies show that O157 at this site are not eliminated by aggressive interventions including applications of O157-specific lytic bacteriophages and other bactericidal agents. We hypothesize that some O157 at the RAJ mucosa are protected from these killing agents by host cell internalization. To test this hypothesis, rectal biopsies from O157 culture positive and negative cattle were analyzed by fluorescent microscopy and subjected to gentamicin protection assays. GFP-labeled bacteria were found located deep within the tissue crypts and a small number of O157 were recovered from rectal biopsies after gentamicin treatment. Primary bovine rectal epithelial (PBRE) cell cultures were incubated with O157 and subjected to gentamicin protection assays. Strains ATCC 43895, 43894, Sakai, and WSU180 entered the PBRE cells with different levels of efficiency ranging from 0.18 to 19.38% of the inocula. Intracellular bacteria were confirmed to be within membrane-bounded vacuoles by electron microscopy. Cytochalasin D curtailed internalization of O157 indicating internalization was dependent on eukaryotic microfilament assembly. Strain ATCC 43895 exhibited the highest efficiency of internalization and survived for at least 24 h within PBRE cells. Deletion mutation of intimin or its receptor in ATCC 43895 did not reduce bacterial internalization. This strain produced more biofilm than the others tested. Retrospective analysis of cattle challenged with two O157 strains, showed ATCC 43895, the most efficient at host cell internalization, was most persistent.
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Affiliation(s)
- Haiqing Sheng
- School of Food Science, University of IdahoMoscow, ID, USA
| | - Jing Wang
- School of Food Science, University of IdahoMoscow, ID, USA
| | - Ji Youn Lim
- School of Food Science, University of IdahoMoscow, ID, USA
- Department of Chemistry, Stanford UniversityStanford, CA, USA
| | - Christine Davitt
- Franceschi Microscopy and Imaging Center, Washington State UniversityPullman, WA, USA
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Bacterial Extracellular Polysaccharides. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 715:213-26. [DOI: 10.1007/978-94-007-0940-9_13] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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35
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Vitamin B6 is required for full motility and virulence in Helicobacter pylori. mBio 2010; 1. [PMID: 21151756 PMCID: PMC3000542 DOI: 10.1128/mbio.00112-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 07/15/2010] [Indexed: 12/16/2022] Open
Abstract
Despite recent advances in our understanding of how Helicobacter pylori causes disease, the factors that allow this pathogen to persist in the stomach have not yet been fully characterized. To identify new virulence factors in H. pylori, we generated low-infectivity variants of a mouse-colonizing H. pylori strain using the classical technique of in vitro attenuation. The resulting variants and their highly infectious progenitor bacteria were then analyzed by global gene expression profiling. The gene expression levels of five open reading frames (ORFs) were significantly reduced in low-infectivity variants, with the most significant changes observed for ORFs HP1583 and HP1582. These ORFs were annotated as encoding homologs of the Escherichia coli vitamin B6 biosynthesis enzymes PdxA and PdxJ. Functional complementation studies with E. coli confirmed H. pylori PdxA and PdxJ to be bona fide homologs of vitamin B6 biosynthesis enzymes. Importantly, H. pylori PdxA was required for optimal growth in vitro and was shown to be essential for chronic colonization in mice. In addition to having a well-known metabolic role, vitamin B6 is necessary for the synthesis of glycosylated flagella and for flagellum-based motility in H. pylori. Thus, for the first time, we identify vitamin B6 biosynthesis enzymes as novel virulence factors in bacteria. Interestingly, pdxA and pdxJ orthologs are present in a number of human pathogens, but not in mammalian cells. We therefore propose that PdxA/J enzymes may represent ideal candidates for therapeutic targets against bacterial pathogens. Approximately half of the world’s population is infected with H. pylori, yet how H. pylori bacteria establish chronic infections in human hosts remains elusive. From gene array studies, we identified two genes as representing potentially novel colonization factors for H. pylori. These genes encoded enzymes involved in the synthesis of vitamin B6, an important molecule for many metabolic reactions in living organisms. Little is currently known regarding vitamin B6 biosynthesis in human pathogens. We showed that mutant H. pylori bacteria lacking an enzyme involved in de novo vitamin B6 biosynthesis, PdxA, were unable to synthesize motility appendages (flagella) and were unable to establish chronic colonization in mice. Thus, this work identifies vitamin B6 biosynthesis enzymes as novel virulence factors for bacterial pathogens. Interestingly, a number of human pathogens, but not their mammalian hosts, possess these genes, which suggests that Pdx enzymes may represent ideal candidates for new therapeutic targets.
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Yamanaka T, Sumita-Sasazaki Y, Sugimori C, Matsumoto-Mashimo C, Yamane K, Mizukawa K, Yoshida M, Hayashi H, Nambu T, Leung KP, Fukushima H. Biofilm-like structures and pathogenicity of Escherichia hermannii YS-11, a clinical isolate from a persistent apical periodontitis lesion. ACTA ACUST UNITED AC 2010; 59:456-65. [PMID: 20553325 DOI: 10.1111/j.1574-695x.2010.00700.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Escherichia hermannii, formerly classified as enteric group 11 of Escherichia coli, is considered to be nonpathogenic. In this report, we described some of the pathogenic properties of a viscous material-producing E. hermannii strain YS-11, which was clinically isolated from a persistent apical periodontitis lesion. YS-11 possessed cell surface-associated meshwork-like structures that are found in some biofilm-forming bacteria and its viscous materials contained mannose-rich exopolysaccharides. To further examine the biological effect of the extracellular viscous materials and the meshwork structures, we constructed a number of mutants using transposon mutagenesis. Strain 455, which has a transposon inserted into wzt, a gene that encodes an ATP-binding cassette transporter, lacked the expression of the cell surface-associated meshwork structures and the ability to produce extracellular materials. Complementation of the disrupted wzt in strain 455 with an intact wzt resulted in the restoration of these phenotypes. We also compared these strains in terms of their ability to induce abscess formation in mice as an indication of their pathogenicity. Strains with meshwork-like structures induced greater abscesses than those induced by strains that lacked such structures. These results suggest that the ability to produce mannose-rich exopolysaccharides and to form meshwork-like structures on E. hermannii might contribute to its pathogenicity.
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Affiliation(s)
- Takeshi Yamanaka
- Department of Bacteriology, Osaka Dental University, Hirakata-shi, Osaka, Japan.
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Chemical sensing in mammalian host-bacterial commensal associations. Proc Natl Acad Sci U S A 2010; 107:9831-6. [PMID: 20457895 DOI: 10.1073/pnas.1002551107] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mammalian gastrointestinal (GI) tract is colonized by a complex consortium of bacterial species. Bacteria engage in chemical signaling to coordinate population-wide behavior. However, it is unclear if chemical sensing plays a role in establishing mammalian host-bacterial commensal relationships. Enterohemorrhagic Escherichia coli (EHEC) is a deadly human pathogen but is a member of the GI flora in cattle, its main reservoir. EHEC harbors SdiA, a regulator that senses acyl-homoserine lactones (AHLs) produced by other bacteria. Here, we show that SdiA is necessary for EHEC colonization of cattle and that AHLs are prominent within the bovine rumen but absent in other areas of the GI tract. We also assessed the rumen metagenome of heifers, and we show that it is dominated by Clostridia and/or Bacilli but also harbors Bacteroidetes. Of note, some members of the Bacteroidetes phyla have been previously reported to produce AHLs. SdiA-AHL chemical signaling aids EHEC in gauging these GI environments, and promotes adaptation to a commensal lifestyle. We show that chemical sensing in the mammalian GI tract determines the niche specificity for colonization by a commensal bacterium of its natural animal reservoir. Chemical sensing may be a general mechanism used by commensal bacteria to sense and adapt to their mammalian hosts. Additionally, because EHEC is largely prevalent in cattle herds, interference with SdiA-mediated cattle colonization is an exciting alternative to diminish contamination of meat products and cross-contamination of produce crops because of cattle shedding of this human pathogen.
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Patrick S, Houston S, Thacker Z, Blakely GW. Mutational analysis of genes implicated in LPS and capsular polysaccharide biosynthesis in the opportunistic pathogen Bacteroides fragilis. MICROBIOLOGY-SGM 2009; 155:1039-1049. [PMID: 19332806 DOI: 10.1099/mic.0.025361-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The obligate anaerobe Bacteroides fragilis is a normal resident of the human gastrointestinal tract. The clinically derived B. fragilis strain NCTC 9343 produces an extensive array of extracellular polysaccharides (EPS), including antigenically distinct large, small and micro- capsules. The genome of NCTC 9343 encodes multiple gene clusters potentially involved in the biosynthesis of EPS, eight of which are implicated in production of the antigenically variable micro-capsule. We have developed a rapid and robust method for generating marked and markerless deletions, together with efficient electroporation using unmodified plasmid DNA to enable complementation of mutations. We show that deletion of a putative wzz homologue prevents production of high-molecular-mass polysaccharides (HMMPS), which form the micro-capsule. This observation suggests that micro-capsule HMMPS constitute the distal component of LPS in B. fragilis. The long chain length of this polysaccharide is strikingly different from classical enteric O-antigen, which consists of short-chain polysaccharides. We also demonstrate that deletion of a putative wbaP homologue prevents expression of the phase-variable large capsule and that expression can be restored by complementation. This suggests that synthesis of the large capsule is mechanistically equivalent to production of Escherichia coli group 1 and 4 capsules.
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Affiliation(s)
- Sheila Patrick
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Rd, Belfast BT9 7BL, UK
| | - Simon Houston
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Rd, Belfast BT9 7BL, UK
| | - Zubin Thacker
- Institute of Cell Biology, University of Edinburgh, Darwin Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
| | - Garry W Blakely
- Institute of Cell Biology, University of Edinburgh, Darwin Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
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Atomic force microscopy study of the role of LPS O-antigen on adhesion ofE. coli. J Mol Recognit 2009; 22:347-55. [DOI: 10.1002/jmr.955] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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O-antigen-negative Salmonella enterica serovar Typhimurium is attenuated in intestinal colonization but elicits colitis in streptomycin-treated mice. Infect Immun 2009; 77:2568-75. [PMID: 19364844 DOI: 10.1128/iai.01537-08] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Lipopolysaccharide (LPS) is a major constituent of the outer membrane and an important virulence factor of Salmonella enterica subspecies 1 serovar Typhimurium (serovar Typhimurium). To evaluate the role of LPS in eliciting intestinal inflammation in streptomycin-treated mice, we constructed an O-antigen-deficient serovar Typhimurium strain through deletion of the wbaP gene. The resulting strain was highly susceptible to human complement activity and the antimicrobial peptide mimic polymyxin B. Furthermore, it showed a severe defect in motility and an attenuated phenotype in a competitive mouse infection experiment, where the DeltawbaP strain (SKI12) was directly compared to wild-type Salmonella. Nevertheless, the DeltawbaP strain (SKI12) efficiently invaded HeLa cells in vitro and elicited acute intestinal inflammation in streptomycin-pretreated mice. Our experiments prove that the presence of complete LPS is not essential for in vitro invasion or for triggering acute colitis.
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Abstract
Enterohemorrhagic Escherichia coli serotype O157:H7 is a pathotype of diarrheagenic E. coli that produces one or more Shiga toxins, forms a characteristic histopathology described as attaching and effacing lesions, and possesses the large virulence plasmid pO157. The bacterium is recognized worldwide, especially in developed countries, as an emerging food-borne bacterial pathogen, which causes disease in humans and in some animals. Healthy cattle are the principal and natural reservoir of E. coli O157:H7, and most disease outbreaks are, therefore, due to consumption of fecally contaminated bovine foods or dairy products. In this review, we provide a general overview of E. coli O157:H7 infection, especially focusing on the bacterial characteristics rather than on the host responses during infection.
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Affiliation(s)
- Jang W Yoon
- Division of Molecular and Life Science, Hanyang University, Ansan 426-791, Korea
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