1
|
Recombinant Escherichia coli BL21 with LngA Variants from ETEC E9034A Promotes Adherence to HT-29 Cells. Pathogens 2023; 12:pathogens12020337. [PMID: 36839609 PMCID: PMC9962868 DOI: 10.3390/pathogens12020337] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023] Open
Abstract
The CS21 pilus produced by enterotoxigenic Escherichia coli (ETEC) is involved in adherence to HT-29 intestinal cells. The CS21 pilus assembles proteins encoded by 14 genes clustered into the lng operon. AIM This study aimed to determine whether E. coli BL21 (ECBL) transformed with the lng operon lacking the lngA gene (pE9034AΔlngA) and complemented in trans with lngA variants of ETEC clinical strains, as well as point substitutions, exhibited modified adherence to HT-29 cells. METHODS A kanamycin cassette was used to replace the lngA gene in the lng operon of the E9034A strain, and the construct was transformed into the ECBL strain. The pJET1.2 vector carrying lngA genes with allelic variants was transformed into ECBLpE9034AΔlngA (ECBLΔlngA). The point substitutions were performed in the pJETlngAFMU073332 vector. RESULTS Bioinformatic alignment analysis of the LngA proteins showed hypervariable regions and clustered the clinical ETEC strains into three groups. Variations in amino acid residues affect the adherence percentages of recombinant ECBL strains with lngA variants and site-specific mutations with HT-29 cells. CONCLUSION In this study, ECBL carrying the lng operon harboring lngA variants of six clinical ETEC strains, as well as point substitutions, exerted an effect on the adherence of ECBL to HT-29 cells, thereby confirming the importance of the CS21 pilus in adherence.
Collapse
|
2
|
Pokharel P, Dhakal S, Dozois CM. The Diversity of Escherichia coli Pathotypes and Vaccination Strategies against This Versatile Bacterial Pathogen. Microorganisms 2023; 11:344. [PMID: 36838308 PMCID: PMC9965155 DOI: 10.3390/microorganisms11020344] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/03/2023] Open
Abstract
Escherichia coli (E. coli) is a gram-negative bacillus and resident of the normal intestinal microbiota. However, some E. coli strains can cause diseases in humans, other mammals and birds ranging from intestinal infections, for example, diarrhea and dysentery, to extraintestinal infections, such as urinary tract infections, respiratory tract infections, meningitis, and sepsis. In terms of morbidity and mortality, pathogenic E. coli has a great impact on public health, with an economic cost of several billion dollars annually worldwide. Antibiotics are not usually used as first-line treatment for diarrheal illness caused by E. coli and in the case of bloody diarrhea, antibiotics are avoided due to the increased risk of hemolytic uremic syndrome. On the other hand, extraintestinal infections are treated with various antibiotics depending on the site of infection and susceptibility testing. Several alarming papers concerning the rising antibiotic resistance rates in E. coli strains have been published. The silent pandemic of multidrug-resistant bacteria including pathogenic E. coli that have become more difficult to treat favored prophylactic approaches such as E. coli vaccines. This review provides an overview of the pathogenesis of different pathotypes of E. coli, the virulence factors involved and updates on the major aspects of vaccine development against different E. coli pathotypes.
Collapse
Affiliation(s)
- Pravil Pokharel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Sabin Dhakal
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Charles M. Dozois
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
- Pasteur Network, Laval, QC H7V 1B7, Canada
| |
Collapse
|
3
|
Smith EM, Grassel CL, Papadimas A, Foulke-Abel J, Barry EM. The role of CFA/I in adherence and toxin delivery by ETEC expressing multiple colonization factors in the human enteroid model. PLoS Negl Trop Dis 2022; 16:e0010638. [PMID: 35881640 PMCID: PMC9355178 DOI: 10.1371/journal.pntd.0010638] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/05/2022] [Accepted: 07/07/2022] [Indexed: 01/10/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a primary causative agent of diarrhea in travelers and young children in low-to-middle-income countries (LMICs). ETEC adhere to intestinal epithelia via colonization factors (CFs) and secrete heat-stable toxin (ST) and/or heat-labile toxin (LT), causing dysregulated cellular ion transport and water secretion. ETEC isolates often harbor genes encoding more than one CF that are targets as vaccine antigens. CFA/I is a major CF that is associated with ETEC that causes moderate-to-severe diarrhea and plays an important role in pathogenesis. The Global Enteric Multicenter Study finding that 78% of CFA/I-expressing ETEC also encode the minor CF CS21 prompted investigation of the combined role of these two CFs. Western blots and electron microscopy demonstrated growth media-dependent and strain-dependent differences in CFA/I and CS21 expression. The critical role of CFA/I in adherence by ETEC strains expressing CFA/I and CS21 was demonstrated using the human enteroid model and a series of CFA/I- and CS21-specific mutants. Furthermore, only anti-CFA/I antibodies inhibited adherence by global ETEC isolates expressing CFA/I and CS21. Delivery of ST and resulting cGMP secretion was measured in supernatants from infected enteroid monolayers, and strain-specific ST delivery and time-dependent cGMP production was observed. Interestingly, cGMP levels were similar across wildtype and CF-deficient strains, reflecting a limitation of this static aerobic infection model. Despite adherence by ETEC and delivery of ST, the enteroid monolayer integrity was not disrupted, as shown by the lack of decrease in transepithelial electrical resistance and the lack of IL-8 cytokines produced during infection. Taken together, these data demonstrate that targeting CFA/I in global clinical CFA/I-CS21 strains is sufficient for adherence inhibition, supporting a vaccine strategy that focuses on blocking major CFs. In addition, the human enteroid model has significant utility for the study of ETEC pathogenesis and evaluation of vaccine-induced functional antibody responses.
Collapse
Affiliation(s)
- Emily M. Smith
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Christen L. Grassel
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Antonia Papadimas
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jennifer Foulke-Abel
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Eileen M. Barry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| |
Collapse
|
4
|
Zhang Y, Tan P, Zhao Y, Ma X. Enterotoxigenic Escherichia coli: intestinal pathogenesis mechanisms and colonization resistance by gut microbiota. Gut Microbes 2022; 14:2055943. [PMID: 35358002 PMCID: PMC8973357 DOI: 10.1080/19490976.2022.2055943] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in children and travelers in developing countries. ETEC is characterized by the ability to produce major virulence factors including colonization factors (CFs) and enterotoxins, that bind to specific receptors on epithelial cells and induce diarrhea. The gut microbiota is a stable and sophisticated ecosystem that performs a range of beneficial functions for the host, including protection against pathogen colonization. Understanding the pathogenic mechanisms of ETEC and the interaction between the gut microbiota and ETEC represents not only a research need but also an opportunity and challenge to develop precautions for ETEC infection. Herein, this review focuses on recent discoveries about ETEC etiology, pathogenesis and clinical manifestation, and discusses the colonization resistances mediated by gut microbiota, as well as preventative strategies against ETEC with an aim to provide novel insights that can reduce the adverse effect on human health.
Collapse
Affiliation(s)
- Yucheng Zhang
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Peng Tan
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Ying Zhao
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| | - Xi Ma
- State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China,CONTACT Xi Ma State Key Laboratory of Animal Nutrition, Department of Animal Nutrition and Feed Science, China Agricultural University, Beijing, China
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Ares MA, Abundes-Gallegos J, Rodríguez-Valverde D, Panunzi LG, Jiménez-Galicia C, Jarillo-Quijada MD, Cedillo ML, Alcántar-Curiel MD, Torres J, Girón JA, De la Cruz MA. The Coli Surface Antigen CS3 of Enterotoxigenic Escherichia coli Is Differentially Regulated by H-NS, CRP, and CpxRA Global Regulators. Front Microbiol 2019; 10:1685. [PMID: 31417507 PMCID: PMC6681793 DOI: 10.3389/fmicb.2019.01685] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/09/2019] [Indexed: 12/16/2022] Open
Abstract
Enterotoxigenic Escherichia coli produces a myriad of adhesive structures collectively named colonization factors (CFs). CS3 is a CF, which is assembled into fine wiry fibrillae encoded by the cstA-H gene cluster. In this work we evaluated the influence of environmental cues such as temperature, osmolarity, pH, and carbon source on the expression of CS3 genes. The transcription of cstH major pilin gene was stimulated by growth of the bacteria in colonization factor broth at 37°C; the presence of glycerol enhanced cstH transcription, while glucose at high concentration, high osmolarity, and the depletion of divalent cations such as calcium and magnesium repressed cstH expression. In addition, we studied the role of H-NS, CpxRA, and CRP global regulators in CS3 gene expression. H-NS and CpxRA acted as repressors and CRP as an activator of cstH expression. Under high osmolarity, H-NS, and CpxRA were required for cstH repression. CS3 was required for both, bacterial adherence to epithelial cells and biofilm formation. Our data strengthens the existence of a multi-factorial regulatory network that controls transcription of CS3 genes in which global regulators, under the influence of environmental signals, control the production of this important intestinal colonization factor.
Collapse
Affiliation(s)
- Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Judith Abundes-Gallegos
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Diana Rodríguez-Valverde
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Leonardo G Panunzi
- Institut Pasteur, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | - César Jiménez-Galicia
- Unidad Médica de Alta Especialidad, Laboratorio Clínico, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Ma Dolores Jarillo-Quijada
- Unidad de Investigacioìn en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Lilia Cedillo
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Marìa D Alcántar-Curiel
- Unidad de Investigacioìn en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Javier Torres
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Jorge A Girón
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| |
Collapse
|
7
|
Genome and Functional Characterization of Colonization Factor Antigen I- and CS6-Encoding Heat-Stable Enterotoxin-Only Enterotoxigenic Escherichia coli Reveals Lineage and Geographic Variation. mSystems 2019; 4:mSystems00329-18. [PMID: 30944874 PMCID: PMC6446980 DOI: 10.1128/msystems.00329-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 12/23/2022] Open
Abstract
Comparative genomics and functional characterization were used to analyze a global collection of CFA/I and CS6 ST-only ETEC isolates associated with human diarrhea, demonstrating differences in the genomic content of CFA/I and CS6 isolates related to CF type, lineage, and geographic location of isolation and also lineage-related differences in ST production. Complete genome sequencing of selected CFA/I and CS6 isolates enabled descriptions of a highly conserved ST-positive (ST+) CFA/I plasmid and of at least five diverse ST and/or CS6 plasmids among the CS6 ETEC isolates. There is currently no approved vaccine for ST-only ETEC, or for any ETEC for that matter, and as such, the current report provides functional verification of ST and CF production and antimicrobial susceptibility testing and an in-depth genomic characterization of a collection of isolates that could serve as representatives of CFA/I- or CS6-encoding ST-only ETEC strains for future studies of ETEC pathogenesis, vaccine studies, and/or clinical trials. Enterotoxigenic Escherichia coli (ETEC) is a significant cause of childhood diarrhea and is a leading cause of traveler’s diarrhea. ETEC strains encoding the heat-stable enterotoxin (ST) are more often associated with childhood diarrhea than ETEC strains that encode only the heat-labile enterotoxin (LT). Colonization factors (CFs) also have a demonstrated role in ETEC virulence, and two of the most prevalent CFs among ETEC that have caused diarrhea are colonization factor antigen I (CFA/I) and CS6. In the current report, we describe the genomes of 269 CS6- or CFA/I-encoding ST-only ETEC isolates that were associated with human diarrhea. While the CS6 and CFA/I ETEC were identified in at least 13 different ETEC genomic lineages, a majority (85%; 229/269) were identified in only six lineages. Complete genome sequencing of selected isolates demonstrated that a conserved plasmid contributed to the dissemination of CFA/I whereas at least five distinct plasmids were involved in the dissemination of ST and/or CS6. Additionally, there were differences in gene content between CFA/I and CS6 ETEC at the phylogroup and lineage levels and in association with their geographic location of isolation as well as lineage-related differences in ST production. Thus, we demonstrate that genomically diverse E. coli strains have acquired ST, as well as CFA/I or CS6, via one or more plasmids and that, in some cases, isolates of a particular lineage or geographic location have undergone additional modifications to their genome content. These findings will aid investigations of virulence and the development of improved diagnostics and vaccines against this important human diarrheal pathogen. IMPORTANCE Comparative genomics and functional characterization were used to analyze a global collection of CFA/I and CS6 ST-only ETEC isolates associated with human diarrhea, demonstrating differences in the genomic content of CFA/I and CS6 isolates related to CF type, lineage, and geographic location of isolation and also lineage-related differences in ST production. Complete genome sequencing of selected CFA/I and CS6 isolates enabled descriptions of a highly conserved ST-positive (ST+) CFA/I plasmid and of at least five diverse ST and/or CS6 plasmids among the CS6 ETEC isolates. There is currently no approved vaccine for ST-only ETEC, or for any ETEC for that matter, and as such, the current report provides functional verification of ST and CF production and antimicrobial susceptibility testing and an in-depth genomic characterization of a collection of isolates that could serve as representatives of CFA/I- or CS6-encoding ST-only ETEC strains for future studies of ETEC pathogenesis, vaccine studies, and/or clinical trials.
Collapse
|
8
|
Vidal RM, Muhsen K, Tennant SM, Svennerholm AM, Sow SO, Sur D, Zaidi AKM, Faruque ASG, Saha D, Adegbola R, Hossain MJ, Alonso PL, Breiman RF, Bassat Q, Tamboura B, Sanogo D, Onwuchekwa U, Manna B, Ramamurthy T, Kanungo S, Ahmed S, Qureshi S, Quadri F, Hossain A, Das SK, Antonio M, Mandomando I, Nhampossa T, Acácio S, Omore R, Ochieng JB, Oundo JO, Mintz ED, O’Reilly CE, Berkeley LY, Livio S, Panchalingam S, Nasrin D, Farag TH, Wu Y, Sommerfelt H, Robins-Browne RM, Del Canto F, Hazen TH, Rasko DA, Kotloff KL, Nataro JP, Levine MM. Colonization factors among enterotoxigenic Escherichia coli isolates from children with moderate-to-severe diarrhea and from matched controls in the Global Enteric Multicenter Study (GEMS). PLoS Negl Trop Dis 2019; 13:e0007037. [PMID: 30608930 PMCID: PMC6343939 DOI: 10.1371/journal.pntd.0007037] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 01/23/2019] [Accepted: 11/28/2018] [Indexed: 12/29/2022] Open
Abstract
Background Enterotoxigenic Escherichia coli (ETEC) encoding heat-stable enterotoxin (ST) alone or with heat-labile enterotoxin (LT) cause moderate-to-severe diarrhea (MSD) in developing country children. The Global Enteric Multicenter Study (GEMS) identified ETEC encoding ST among the top four enteropathogens. Since the GEMS objective was to provide evidence to guide development and implementation of enteric vaccines and other interventions to diminish diarrheal disease morbidity and mortality, we examined colonization factor (CF) prevalence among ETEC isolates from children age <5 years with MSD and from matched controls in four African and three Asian sites. We also assessed strength of association of specific CFs with MSD. Methodology/Principal findings MSD cases enrolled at healthcare facilities over three years and matched controls were tested in a standardized manner for many enteropathogens. To identify ETEC, three E. coli colonies per child were tested by polymerase chain reaction (PCR) to detect genes encoding LT, ST; confirmed ETEC were examined by PCR for major CFs (Colonization Factor Antigen I [CFA/I] or Coli Surface [CS] antigens CS1-CS6) and minor CFs (CS7, CS12, CS13, CS14, CS17, CS18, CS19, CS20, CS21, CS30). ETEC from 806 cases had a single toxin/CF profile in three tested strains per child. Major CFs, components of multiple ETEC vaccine candidates, were detected in 66.0% of LT/ST and ST-only cases and were associated with MSD versus matched controls by conditional logistic regression (p≤0.006); major CFs detected in only 25.0% of LT-only cases weren’t associated with MSD. ETEC encoding exclusively CS14, identified among 19.9% of 291 ST-only and 1.5% of 259 LT/ST strains, were associated with MSD (p = 0.0011). No other minor CF exhibited prevalence ≥5% and significant association with MSD. Conclusions/Significance Major CF-based efficacious ETEC vaccines could potentially prevent up to 66% of pediatric MSD cases due to ST-encoding ETEC in developing countries; adding CS14 extends coverage to ~77%. Enterotoxigenic Escherichia coli (“ETEC”) were found to be one of the four most consistently important agents that cause moderate-to-severe diarrhea among children <5 years of age in a large case-control study, the Global Enteric Multicenter Study, performed in four countries in sub-Saharan Africa and three in South Asia. ETEC attach to the lining of the human small intestine by means of protein colonization factors (CFs), after which bacterial toxins stimulate intestinal secretion resulting in diarrhea. Moderate-to-severe diarrhea in young children in developing countries can lead to malnutrition and death. Vaccines are being developed to prevent ETEC diarrhea and its consequences. Several ETEC vaccines aim to stimulate antibodies (protective proteins) that will bind CFs and prevent the bacteria from attaching to intestinal cells, which should, in turn, prevent ETEC diarrhea. Different types of CFs exist. To guide the development of vaccines intending to provide broad protection against ETEC, one must know the frequency with which the different major CFs are produced by ETEC. This paper reports an extensive systematic survey of ETEC CFs and provides helpful information to guide the development of ETEC vaccines.
Collapse
Affiliation(s)
- Roberto M. Vidal
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Khitam Muhsen
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Sharon M. Tennant
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Ann-Mari Svennerholm
- Department of Microbiology and Immunology at Institute of Biomedicine, University of Göteborg, Göteborg, Sweden
| | - Samba O. Sow
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Dipika Sur
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Anita K. M. Zaidi
- Department of Paediatrics and Child Health, the Aga Khan University, Karachi, Pakistan
| | - Abu S. G. Faruque
- International Centre for Diarrhoeal Disease Research, Mohakhali, Dhaka, Bangladesh
| | - Debasish Saha
- Medical Research Council (United Kingdom) Unit, Fajara, The Gambia
| | - Richard Adegbola
- Medical Research Council (United Kingdom) Unit, Fajara, The Gambia
| | | | - Pedro L. Alonso
- Centro de Investigação em Saúde da Manhiça, Maputo, Mozambique
- ISGlobal, Barcelona Ctr. Int. Health Res. Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Robert F. Breiman
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
- Global Disease Detection Division, Kenya Office of the US Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Quique Bassat
- Centro de Investigação em Saúde da Manhiça, Maputo, Mozambique
- ISGlobal, Barcelona Ctr. Int. Health Res. Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Boubou Tamboura
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Doh Sanogo
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Uma Onwuchekwa
- Centre pour le Développement des Vaccins du Mali (CVD-Mali), Bamako, Mali
| | - Byomkesh Manna
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | | | - Suman Kanungo
- National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shahnawaz Ahmed
- International Centre for Diarrhoeal Disease Research, Mohakhali, Dhaka, Bangladesh
| | - Shahida Qureshi
- Department of Paediatrics and Child Health, the Aga Khan University, Karachi, Pakistan
| | - Farheen Quadri
- Department of Paediatrics and Child Health, the Aga Khan University, Karachi, Pakistan
| | - Anowar Hossain
- International Centre for Diarrhoeal Disease Research, Mohakhali, Dhaka, Bangladesh
| | - Sumon K. Das
- International Centre for Diarrhoeal Disease Research, Mohakhali, Dhaka, Bangladesh
| | - Martin Antonio
- Medical Research Council (United Kingdom) Unit, Fajara, The Gambia
| | | | | | - Sozinho Acácio
- Centro de Investigação em Saúde da Manhiça, Maputo, Mozambique
| | - Richard Omore
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - John B. Ochieng
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Joseph O. Oundo
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Eric D. Mintz
- Division of Foodborne, Waterborne and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Ciara E. O’Reilly
- Division of Foodborne, Waterborne and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Lynette Y. Berkeley
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Sofie Livio
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Sandra Panchalingam
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Dilruba Nasrin
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Tamer H. Farag
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Yukun Wu
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Halvor Sommerfelt
- Centre of Intervention Science in Maternal and Child Health, Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
- Norwegian Institute of Public Health, Oslo, Norway
| | - Roy M. Robins-Browne
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria, Australia
| | - Felipe Del Canto
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Tracy H. Hazen
- The Institute of Genomic Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - David A. Rasko
- The Institute of Genomic Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Karen L. Kotloff
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - James P. Nataro
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Myron M. Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
- * E-mail:
| |
Collapse
|
9
|
Interplay of a secreted protein with type IVb pilus for efficient enterotoxigenic Escherichia coli colonization. Proc Natl Acad Sci U S A 2018; 115:7422-7427. [PMID: 29941571 PMCID: PMC6048534 DOI: 10.1073/pnas.1805671115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To avoid the mucosal barrier and attach to the intestinal epithelium, enteric pathogens have evolved a unique proteinaceous fiber called type IVb pilus (T4bP). Despite its importance for bacterial pathogenesis, little is known about the adhesion mechanisms of T4bP, especially regarding the role of the minor pilin subunit located at its tip. Here, we show that the type IVb minor pilin CofB of CFA/III from enterotoxigenic Escherichia coli (ETEC) plays a role not only in T4bP assembly by forming a trimeric initiator complex, but also in bacterial adhesion by anchoring a secreted protein, CofJ, at the trimerization interface of H-type lectin domain. These findings expand our knowledge of T4P biology and provide important insights for developing therapeutics against ETEC infection. Initial attachment and subsequent colonization of the intestinal epithelium comprise critical events allowing enteric pathogens to survive and express their pathogenesis. In enterotoxigenic Escherichia coli (ETEC), these are mediated by a long proteinaceous fiber termed type IVb pilus (T4bP). We have reported that the colonization factor antigen/III (CFA/III), an operon-encoded T4bP of ETEC, possesses a minor pilin, CofB, that carries an H-type lectin domain at its tip. Although CofB is critical for pilus assembly by forming a trimeric initiator complex, its importance for bacterial attachment remains undefined. Here, we show that T4bP is not sufficient for bacterial attachment, which also requires a secreted protein CofJ, encoded within the same CFA/III operon. The crystal structure of CofB complexed with a peptide encompassing the binding region of CofJ showed that CofJ interacts with CofB by anchoring its flexible N-terminal extension to be embedded deeply into the expected carbohydrate recognition site of the CofB H-type lectin domain. By combining this structure and physicochemical data in solution, we built a plausible model of the CofJ–CFA/III pilus complex, which suggested that CofJ acts as a molecular bridge by binding both T4bP and the host cell membrane. The Fab fragments of a polyclonal antibody against CofJ significantly inhibited bacterial attachment by preventing the adherence of secreted CofJ proteins. These findings signify the interplay between T4bP and a secreted protein for attaching to and colonizing the host cell surface, potentially constituting a therapeutic target against ETEC infection.
Collapse
|
10
|
Rossi E, Cimdins A, Lüthje P, Brauner A, Sjöling Å, Landini P, Römling U. "It's a gut feeling" - Escherichia coli biofilm formation in the gastrointestinal tract environment. Crit Rev Microbiol 2017; 44:1-30. [PMID: 28485690 DOI: 10.1080/1040841x.2017.1303660] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Escherichia coli can commonly be found, either as a commensal, probiotic or a pathogen, in the human gastrointestinal (GI) tract. Biofilm formation and its regulation is surprisingly variable, although distinct regulatory pattern of red, dry and rough (rdar) biofilm formation arise in certain pathovars and even clones. In the GI tract, environmental conditions, signals from the host and from commensal bacteria contribute to shape E. coli biofilm formation within the multi-faceted multicellular communities in a complex and integrated fashion. Although some major regulatory networks, adhesion factors and extracellular matrix components constituting E. coli biofilms have been recognized, these processes have mainly been characterized in vitro and in the context of interaction of E. coli strains with intestinal epithelial cells. However, direct observation of E. coli cells in situ, and the vast number of genes encoding surface appendages on the core or accessory genome of E. coli suggests the complexity of the biofilm process to be far from being fully understood. In this review, we summarize biofilm formation mechanisms of commensal, probiotic and pathogenic E. coli in the context of the gastrointestinal tract.
Collapse
Affiliation(s)
- Elio Rossi
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy.,b Novo Nordisk Center for Biosustainabiliy , Technical University of Denmark , Kgs. Lyngby , Denmark
| | - Annika Cimdins
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,d Institute of Hygiene, University of Münster , Münster , Germany
| | - Petra Lüthje
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,e Division of Clinical Microbiology, Department of Laboratory Medicine , Karolinska Institutet and Karolinska University Hospital Huddinge , Stockholm , Sweden
| | - Annelie Brauner
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Åsa Sjöling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Paolo Landini
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy
| | - Ute Römling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| |
Collapse
|
11
|
De la Cruz MA, Ruiz-Tagle A, Ares MA, Pacheco S, Yáñez JA, Cedillo L, Torres J, Girón JA. The expression of Longus type 4 pilus of enterotoxigenic Escherichia coli is regulated by LngR and LngS and by H-NS, CpxR and CRP global regulators. Environ Microbiol 2017; 19:1761-1775. [PMID: 27943535 DOI: 10.1111/1462-2920.13644] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/30/2016] [Accepted: 12/04/2016] [Indexed: 12/31/2022]
Abstract
Enterotoxigenic Escherichia coli produces a long type 4 pilus called Longus. The regulatory elements and the environmental signals controlling the expression of Longus-encoding genes are unknown. We identified two genes lngR and lngS in the Longus operon, whose predicted products share homology with transcriptional regulators. Isogenic lngR and lngS mutants were considerably affected in transcription of lngA pilin gene. The expression of lngA, lngR and lngS genes was optimally expressed at 37°C at pH 7.5. The presence of glucose and sodium chloride had a positive effect on Longus expression. The presence of divalent ions, particularly calcium, appears to be an important stimulus for Longus production. In addition, we studied H-NS, CpxR and CRP global regulators, on Longus expression. The response regulator CpxR appears to function as a positive regulator of lng genes as the cpxR mutant showed reduced levels of lngRSA expression. In contrast, H-NS and CRP function as negative regulators since expression of lngA was up-regulated in isogenic hns and crp mutants. H-NS and CRP were required for salt- and glucose-mediated regulation of Longus. Our data suggest the existence of a complex regulatory network controlling Longus expression, involving both local and global regulators in response to different environmental signals.
Collapse
Affiliation(s)
- Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI IMSS, Mexico City, Mexico
| | | | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI IMSS, Mexico City, Mexico
| | - Sabino Pacheco
- Departamento de Microbiología Molecular, Instituto de Biotecnología UNAM, Cuernavaca, Mexico
| | - Jorge A Yáñez
- Facultad de Estomatología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Lilia Cedillo
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Javier Torres
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI IMSS, Mexico City, Mexico
| | - Jorge A Girón
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.,Department of Pediatrics, University of Virginia, Charlottesville, VA, 22908, USA
| |
Collapse
|
12
|
Ng D, Harn T, Altindal T, Kolappan S, Marles JM, Lala R, Spielman I, Gao Y, Hauke CA, Kovacikova G, Verjee Z, Taylor RK, Biais N, Craig L. The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus. PLoS Pathog 2016; 12:e1006109. [PMID: 27992883 PMCID: PMC5207764 DOI: 10.1371/journal.ppat.1006109] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/03/2017] [Accepted: 12/02/2016] [Indexed: 01/03/2023] Open
Abstract
Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system. Bacterial pathogens utilize a number of highly complex and sophisticated molecular systems to colonize their hosts and alter them, creating customized niches in which to reproduce. One such system is the Type IV pilus system, made up of dozens of proteins that form a macromolecular machine to polymerize small pilin proteins into long thin filaments that are displayed on the bacterial surface. These pili have a remarkable array of functions that rely on their ability to (i) adhere to many substrates, including host cell surfaces, pili from nearby bacteria, DNA and bacterial viruses (bacteriophage), and (ii) to depolymerize or retract, which pulls the bacteria along mucosal surfaces, pulls them close together in protective aggregates, and can even draw in substrates like DNA and bacteriophage for nutrition and genetic variation. For most Type IV pilus systems, retraction is an energy-driven process facilitated by a retraction ATPase. We show here that in the simplest of the Type IV pilus systems, the Vibrio cholerae toxin-coregulated pilus, a pilin-like protein initiates pilus retraction by what appears to be mechanical rather than enzymatic means. Our results provide a framework for understanding more complex Type IV pili and the related Type II secretion systems, which represent targets for novel highly specific antibiotics.
Collapse
Affiliation(s)
- Dixon Ng
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Tony Harn
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Tuba Altindal
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Subramania Kolappan
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Jarrad M. Marles
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Rajan Lala
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
| | - Ingrid Spielman
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
| | - Yang Gao
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Caitlyn A. Hauke
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Gabriela Kovacikova
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Zia Verjee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Ronald K. Taylor
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Nicolas Biais
- Biology Department, Brooklyn College, City University of New York, Brooklyn, New York, United States of America
- Graduate Center, City University of New York, Brooklyn, New York, United States of America
- * E-mail: (LC); (NB)
| | - Lisa Craig
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail: (LC); (NB)
| |
Collapse
|
13
|
Saldaña-Ahuactzi Z, Rodea GE, Cruz-Córdova A, Rodríguez-Ramírez V, Espinosa-Mazariego K, González-Montalvo MA, Ochoa SA, González-Pedrajo B, Eslava-Campos CA, López-Villegas EO, Hernández-Castro R, Arellano-Galindo J, Patiño-López G, Xicohtencatl-Cortes J. Effects of lng Mutations on LngA Expression, Processing, and CS21 Assembly in Enterotoxigenic Escherichia coli E9034A. Front Microbiol 2016; 7:1201. [PMID: 27536289 PMCID: PMC4971541 DOI: 10.3389/fmicb.2016.01201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a major cause of morbidity in children under 5 years of age in low- and middle-income countries and a leading cause of traveler's diarrhea worldwide. The ability of ETEC to colonize the intestinal epithelium is mediated by fimbrial adhesins, such as CS21 (Longus). This adhesin is a type IVb pilus involved in adherence to intestinal cells in vitro and bacterial self-aggregation. Fourteen open reading frames have been proposed to be involved in CS21 assembly, hitherto only the lngA and lngB genes, coding for the major (LngA) and minor (LngB) structural subunit, have been characterized. In this study, we investigated the role of the LngA, LngB, LngC, LngD, LngH, and LngP proteins in the assembly of CS21 in ETEC strain E9034A. The deletion of the lngA, lngB, lngC, lngD, lngH, or lngP genes, abolished CS21 assembly in ETEC strain E9034A and the adherence to HT-29 cells was reduced 90%, compared to wild-type strain. Subcellular localization prediction of CS21 proteins was similar to other well-known type IV pili homologs. We showed that LngP is the prepilin peptidase of LngA, and that ETEC strain E9034A has another peptidase capable of processing LngA, although with less efficiency. Additionally, we present immuno-electron microscopy images to show that the LngB protein could be localized at the tip of CS21. In conclusion, our results demonstrate that the LngA, LngB, LngC, LngD, LngH, and LngP proteins are essential for CS21 assembly, as well as for bacterial aggregation and adherence to HT-29 cells.
Collapse
Affiliation(s)
- Zeus Saldaña-Ahuactzi
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico GómezCiudad de México, Mexico; Instituto de Fisiología Celular at the Universidad Nacional Autónoma de MéxicoCiudad de México, Mexico
| | - Gerardo E Rodea
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico GómezCiudad de México, Mexico; Instituto de Fisiología Celular at the Universidad Nacional Autónoma de MéxicoCiudad de México, Mexico
| | - Ariadnna Cruz-Córdova
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| | - Viridiana Rodríguez-Ramírez
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| | - Karina Espinosa-Mazariego
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| | - Martín A González-Montalvo
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| | - Sara A Ochoa
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Carlos A Eslava-Campos
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Edgar O López-Villegas
- Laboratorio Central de Microscopía, Departamento de Investigación-SEPI, Instituto Politecnico Nacional Ciudad de México, Mexico
| | - Rigoberto Hernández-Castro
- Departamento de Ecología de Agentes Patógenos, Hospital General "Dr. Manuel Gea González" Ciudad de México, Mexico
| | - José Arellano-Galindo
- Departamento de Infectología, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| | - Genaro Patiño-López
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| | - Juan Xicohtencatl-Cortes
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico
| |
Collapse
|
14
|
Nandre RM, Ruan X, Duan Q, Sack DA, Zhang W. Antibodies derived from an enterotoxigenic Escherichia coli (ETEC) adhesin tip MEFA (multiepitope fusion antigen) against adherence of nine ETEC adhesins: CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, CS21 and EtpA. Vaccine 2016; 34:3620-5. [PMID: 27228947 DOI: 10.1016/j.vaccine.2016.04.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/17/2016] [Accepted: 04/01/2016] [Indexed: 10/21/2022]
Abstract
Diarrhea continues to be a leading cause of death in children younger than 5 years in developing countries. Enterotoxigenic Escherichia coli (ETEC) is a leading bacterial cause of children's diarrhea and travelers' diarrhea. ETEC bacteria initiate diarrheal disease by attaching to host receptors at epithelial cells and colonizing in small intestine. Therefore, preventing ETEC attachment has been considered the first line of defense against ETEC diarrhea. However, developing vaccines effectively against ETEC bacterial attachment encounters challenge because ETEC strains produce over 23 immunologically heterogeneous adhesins. In this study, we applied MEFA (multiepitope fusion antigen) approach to integrate epitopes from adhesin tips or adhesive subunits of CFA/I, CS1, CS2, CS3, CS4, CS5, CS6, CS21 and EtpA adhesins and to construct an adhesin tip MEFA peptide. We then examined immunogenicity of this tip MEFA in mouse immunization, and assessed potential application of this tip MEFA for ETEC vaccine development. Data showed that mice intraperitoneally immunized with this adhesin tip MEFA developed IgG antibody responses to all nine ETEC adhesins. Moreover, ETEC and E. coli bacteria expressing these nine adhesins, after incubation with serum of the immunized mice, exhibited significant reduction in attachment to Caco-2 cells. These results indicated that anti-adhesin antibodies induced by this adhesin tip MEFA blocked adherence of the most important ETEC adhesins, suggesting this multivalent tip MEFA may be useful for developing a broadly protective anti-adhesin vaccine against ETEC diarrhea.
Collapse
Affiliation(s)
- Rahul M Nandre
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS, USA
| | - Xiaosai Ruan
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS, USA
| | - Qiangde Duan
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS, USA
| | - David A Sack
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Weiping Zhang
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS, USA.
| |
Collapse
|
15
|
Zhang C, Iqbal J, Gómez-Duarte OG. Murine immunization with CS21 pili or LngA major subunit of enterotoxigenic Escherichia coli (ETEC) elicits systemic and mucosal immune responses and inhibits ETEC gut colonization. Vet Microbiol 2016; 202:90-100. [PMID: 26878971 DOI: 10.1016/j.vetmic.2016.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/24/2016] [Accepted: 02/04/2016] [Indexed: 02/07/2023]
Abstract
CS21 pili of enterotoxigenic Escherichia coli (ETEC) is one of the most prevalent ETEC colonization factors. CS21 major subunit, LngA, mediates ETEC adherence to intestinal cells, and contributes to ETEC pathogenesis in a neonatal mouse infection model. The objectives of this work were to evaluate LngA major subunit purified protein and CS21 purified pili on immunogenicity and protection against ETEC colonization of mice intestine. Recombinant LngA purified protein or purified CS21 pili from E9034A ETEC strain were evaluated for immunogenicity after immunization of C57BL/6 mice. Specific anti-LngA antibodies were detected from mice serum, feces, and intestine fluid samples by ELISA assays. Protection against gut colonization was evaluated on immunized mice orally challenged with wild type E9034A ETEC strain and by subsequent quantification of bacterial colony forming units (CFU) recovered from feces. Recombinant LngA protein and CS21 pili induced specific humoral and mucosal anti-LngA antibodies in the mouse model. CS21 combined with CT delivered intranasally as well as LngA combined with incomplete Freund adjuvant delivered intraperitoneally inhibited ETEC gut colonization in a mouse model. In conclusion, both LngA purified protein and CS21 pili from ETEC are highly immunogenic and may inhibit ETEC intestinal shedding. Our data on immunogenicity and immunoprotection indicates that CS21 is a suitable vaccine candidate for a future multivalent vaccine against ETEC diarrhea.
Collapse
Affiliation(s)
- Chengxian Zhang
- Division of Infectious Diseases, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Junaid Iqbal
- Division of Infectious Diseases, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Oscar G Gómez-Duarte
- Division of Infectious Diseases, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA.
| |
Collapse
|
16
|
Sure S, Torriero AAJ, Gaur A, Li LH, Chen Y, Tripathi C, Adholeya A, Ackland ML, Kochar M. Identification and topographical characterisation of microbial nanowires in Nostoc punctiforme. Antonie Van Leeuwenhoek 2016; 109:475-80. [PMID: 26754102 DOI: 10.1007/s10482-015-0644-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 12/30/2015] [Indexed: 11/28/2022]
Abstract
Extracellular pili-like structures (PLS) produced by cyanobacteria have been poorly explored. We have done detailed topographical and electrical characterisation of PLS in Nostoc punctiforme PCC 73120 using transmission electron microscopy (TEM) and conductive atomic force microscopy (CAFM). TEM analysis showed that N. punctiforme produces two separate types of PLS differing in their length and diameter. The first type of PLS are 6-7.5 nm in diameter and 0.5-2 µm in length (short/thin PLS) while the second type of PLS are ~20-40 nm in diameter and more than 10 µm long (long/thick PLS). This is the first study to report long/thick PLS in N. punctiforme. Electrical characterisation of these two different PLS by CAFM showed that both are electrically conductive and can act as microbial nanowires. This is the first report to show two distinct PLS and also identifies microbial nanowires in N. punctiforme. This study paves the way for more detailed investigation of N. punctiforme nanowires and their potential role in cell physiology and symbiosis with plants.
Collapse
Affiliation(s)
- Sandeep Sure
- TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gual Pahari, Gurgaon-Faridabad Road, Gurgaon, Haryana, 122 001, India
| | - Angel A J Torriero
- Centre for Cellular & Molecular Biology, Deakin University, 221 Burwood Highway, Burwood, Melbourne, VIC, 3125, Australia
| | - Aditya Gaur
- TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gual Pahari, Gurgaon-Faridabad Road, Gurgaon, Haryana, 122 001, India
| | - Lu Hua Li
- Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Geelong, VIC, 3216, Australia
| | - Ying Chen
- Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Geelong, VIC, 3216, Australia
| | - Chandrakant Tripathi
- TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gual Pahari, Gurgaon-Faridabad Road, Gurgaon, Haryana, 122 001, India
| | - Alok Adholeya
- TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gual Pahari, Gurgaon-Faridabad Road, Gurgaon, Haryana, 122 001, India
| | - M Leigh Ackland
- Centre for Cellular & Molecular Biology, Deakin University, 221 Burwood Highway, Burwood, Melbourne, VIC, 3125, Australia
| | - Mandira Kochar
- TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gual Pahari, Gurgaon-Faridabad Road, Gurgaon, Haryana, 122 001, India.
| |
Collapse
|
17
|
Fleckenstein JM, Rasko DA. Overcoming Enterotoxigenic Escherichia coli Pathogen Diversity: Translational Molecular Approaches to Inform Vaccine Design. Methods Mol Biol 2016; 1403:363-83. [PMID: 27076141 DOI: 10.1007/978-1-4939-3387-7_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) are a genetically diverse E. coli pathovar that share in the ability to produce heat-labile toxin and/or heat-stable toxins. While these pathogens contribute substantially to the burden of diarrheal illness in developing countries, at present, there is no suitable broadly protective vaccine to prevent these common infections. Most vaccine development attempts to date have followed a classical approach involving a relatively small group of antigens. The extraordinary underlying genetic plasticity of E. coli has confounded the antigen valency requirements based on this approach. The recent discovery of additional virulence proteins within this group of pathogens, as well as the availability of whole-genome sequences from hundreds of ETEC strains to facilitate identification of conserved molecules, now permits a reconsideration of the classical approaches, and the exploration of novel antigenic targets to complement existing strategies overcoming antigenic diversity that has impeded progress toward a broadly protective vaccine. Progress to date in antigen discovery and methods currently available to explore novel immunogens are outlined here.
Collapse
Affiliation(s)
- James M Fleckenstein
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, Campus Box 8051, 660 South Euclid Avenue, St. Louis, MO, USA.
- Molecular Microbiology and Molecular Pathogenesis Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA.
- Medicine Service, Veterans Affairs Medical Center, St. Louis, MO, USA.
| | - David A Rasko
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
18
|
Abstract
Proteinaceous, nonflagellar surface appendages constitute a variety of structures, including those known variably as fimbriae or pili. Constructed by distinct assembly pathways resulting in diverse morphologies, fimbriae have been described to mediate functions including adhesion, motility, and DNA transfer. As these structures can represent major diversifying elements among Escherichia and Salmonella isolates, multiple fimbrial classification schemes have been proposed and a number of mechanistic insights into fimbrial assembly and function have been made. Herein we describe the classifications and biochemistry of fimbriae assembled by the chaperone/usher, curli, and type IV pathways.
Collapse
|
19
|
Kolappan S, Ng D, Yang G, Harn T, Craig L. Crystal Structure of the Minor Pilin CofB, the Initiator of CFA/III Pilus Assembly in Enterotoxigenic Escherichia coli. J Biol Chem 2015; 290:25805-18. [PMID: 26324721 DOI: 10.1074/jbc.m115.676106] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Indexed: 01/04/2023] Open
Abstract
Type IV pili are extracellular polymers of the major pilin subunit. These subunits are held together in the pilus filament by hydrophobic interactions among their N-terminal α-helices, which also anchor the pilin subunits in the inner membrane prior to pilus assembly. Type IV pilus assembly involves a conserved group of proteins that span the envelope of Gram-negative bacteria. Among these is a set of minor pilins, so named because they share their hydrophobic N-terminal polymerization/membrane anchor segment with the major pilins but are much less abundant. Minor pilins influence pilus assembly and retraction, but their precise functions are not well defined. The Type IV pilus systems of enterotoxigenic Escherichia coli and Vibrio cholerae are among the simplest of Type IV pilus systems and possess only a single minor pilin. Here we show that the enterotoxigenic E. coli minor pilins CofB and LngB are required for assembly of their respective Type IV pili, CFA/III and Longus. Low levels of the minor pilins are optimal for pilus assembly, and CofB can be detected in the pilus fraction. We solved the 2.0 Å crystal structure of N-terminally truncated CofB, revealing a pilin-like protein with an extended C-terminal region composed of two discrete domains connected by flexible linkers. The C-terminal region is required for CofB to initiate pilus assembly. We propose a model for CofB-initiated pilus assembly with implications for understanding filament growth in more complex Type IV pilus systems as well as the related Type II secretion system.
Collapse
Affiliation(s)
- Subramania Kolappan
- From the Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Dixon Ng
- From the Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Guixiang Yang
- From the Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Tony Harn
- From the Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Lisa Craig
- From the Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| |
Collapse
|
20
|
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a major cause of life-threatening diarrheal disease around the world. The major aspects of ETEC virulence are colonization of the small intestine and the secretion of enterotoxins which elicit diarrhea. Intestinal colonization is mediated, in part, by adhesins displayed on the bacterial cell surface. As colonization of the intestine is the critical first step in the establishment of an infection, it represents a potential point of intervention for the prevention of infections. Therefore, colonization factors (CFs) have been important subjects of research in the field of ETEC virulence. Research in this field has revealed that ETEC possesses a large array of serologically distinct CFs that differ in composition, structure, and function. Most ETEC CFs are pili (fimbriae) or related fibrous structures, while other adhesins are simple outer membrane proteins lacking any macromolecular structure. This chapter reviews the genetics, structure, function, and regulation of ETEC CFs and how such studies have contributed to our understanding of ETEC virulence and opened up potential opportunities for the development of preventive and therapeutic interventions.
Collapse
|
21
|
Cruz-Córdova A, Espinosa-Mazariego K, Ochoa SA, Saldaña Z, Rodea GE, Cázares-Domínguez V, Rodríguez-Ramírez V, Eslava-Campos CA, Navarro-Ocaña A, Arrellano-Galindo J, Hernández-Castro R, Gómez-Duarte OG, Qadri F, Xicohtencatl-Cortes J. CS21 positive multidrug-resistant ETEC clinical isolates from children with diarrhea are associated with self-aggregation, and adherence. Front Microbiol 2014; 5:709. [PMID: 25646093 PMCID: PMC4297921 DOI: 10.3389/fmicb.2014.00709] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/28/2014] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Enterotoxigenic Escherichia coli (ETEC) colonize the human intestinal mucosa using pili and non-pili colonization factors (CFs). CS21 (also designated Longus) is one of the most prevalent CFs encoded by a 14 kb lng DNA cluster located in a virulence plasmid of ETEC; yet limited information is available on the prevalence of CS21 positive ETEC isolates in different countries. The aim of this study was to evaluate the prevalence of CS21 among ETEC clinical isolates from Mexican and Bangladeshi children under 5 years old with diarrhea and to determine the phenotypic and genotypic features of these isolates. METHODS ETEC clinical isolates positive to lngA gene were characterized by genotype, multidrug-resistance, self-aggregation, biofilm formation, and adherence to HT-29 cell line. RESULTS A collection of 303 E. coli clinical isolates were analyzed, the 81.51% (247/303) were identified as ETEC, 30.76% (76/247) were st (+)/lt (+), and 25.10% (62/247) were positive for the lngA gene. Among the lngA (+) ETECs identified, 50% of isolates (31/62) were positive for LngA protein. The most frequent serotype was O128ac:H12 found in 19.35% (12/62) of lngA (+) ETEC studied. Multidrug-resistance (MDR) lngA (+) ETEC isolates was identified in 65% (39/60), self-aggregation in 48.38% (30/62), and biofilm formation in 83.87% (52/62). ETEC lngA (+) isolates were able to adhere to HT-29 cells at different levels. Two lngA isogenic mutants were constructed in the ETEC E9034A and ETEC73332 clinical isolate, showing a 77% and 98% reduction in adherence, respectively with respect to the wild type. CONCLUSION ETEC isolates that have the lngA gene showed features associated with self-aggregation, and adherence to HT-29 cells, important characteristics in the human gut colonization process and pathogenesis.
Collapse
Affiliation(s)
- Ariadnna Cruz-Córdova
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico
| | - Karina Espinosa-Mazariego
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico
| | - Sara A Ochoa
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico
| | - Zeus Saldaña
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico ; Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Mexico City, Mexico
| | - Gerardo E Rodea
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico ; Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Mexico City, Mexico
| | - Vicenta Cázares-Domínguez
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico
| | - Viridiana Rodríguez-Ramírez
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico
| | - Carlos A Eslava-Campos
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Patogenicidad Bacteriana, Hospital Infantil de México Federico Gómez Mexico City, Mexico ; Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México Mexico City, Mexico
| | - Armando Navarro-Ocaña
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México Mexico City, Mexico
| | - José Arrellano-Galindo
- Laboratorio de Infectología, Departamento de Infectología, Hospital Infantil de México Federico Gómez Mexico City, Mexico
| | - Rigoberto Hernández-Castro
- Departamento de Ecología de Agentes Patógenos, Hospital General "Dr. Manuel Gea González," Mexico City, Mexico
| | - Oscar G Gómez-Duarte
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University School of Medicine Nashville, TN, USA
| | - Firdausi Qadri
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research Dhaka, Bangladesh
| | - Juan Xicohtencatl-Cortes
- Unidad de Hemato-Onocología e Investigación, Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez Mexico City, Mexico
| |
Collapse
|
22
|
Yuen ASW, Kolappan S, Ng D, Craig L. Structure and secretion of CofJ, a putative colonization factor of enterotoxigenic Escherichia coli. Mol Microbiol 2013; 90:898-918. [PMID: 24106767 DOI: 10.1111/mmi.12407] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2013] [Indexed: 01/19/2023]
Abstract
Enterotoxigenic Escherichia coli (ETEC) colonize the human gut, causing severe cholera-like diarrhoea. ETEC utilize a diverse array of pili and fimbriae for host colonization, including the Type IVb pilus CFA/III. The CFA/III pilus machinery is encoded on the cof operon, which is similar in gene sequence and synteny to the tcp operon that encodes another Type IVb pilus, the Vibrio cholerae toxin co-regulated pilus (TCP). Both pilus operons possess a syntenic gene encoding a protein of unknown function. In V. cholerae, this protein, TcpF, is a critical colonization factor secreted by the TCP apparatus. Here we show that the corresponding ETEC protein, CofJ, is a soluble protein secreted via the CFA/III apparatus. We present a 2.6 Å resolution crystal structure of CofJ, revealing a large β-sandwich protein that bears no sequence or structural homology to TcpF. CofJ has a cluster of exposed hydrophobic side-chains at one end and structural homology to the pore-forming proteins perfringolysin O and α-haemolysin. CofJ binds to lipid vesicles and epithelial cells, suggesting a role in membrane attachment during ETEC colonization.
Collapse
Affiliation(s)
- Alex S W Yuen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | | | | | | |
Collapse
|
23
|
Structural characterization of CFA/III and Longus type IVb pili from enterotoxigenic Escherichia coli. J Bacteriol 2012; 194:2725-35. [PMID: 22447901 DOI: 10.1128/jb.00282-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The type IV pili are helical filaments found on many Gram-negative pathogenic bacteria, with multiple diverse roles in pathogenesis, including microcolony formation, adhesion, and twitching motility. Many pathogenic enterotoxigenic Escherichia coli (ETEC) isolates express one of two type IV pili belonging to the type IVb subclass: CFA/III or Longus. Here we show a direct correlation between CFA/III expression and ETEC aggregation, suggesting that these pili, like the Vibrio cholerae toxin-coregulated pili (TCP), mediate microcolony formation. We report a 1.26-Å resolution crystal structure of CofA, the major pilin subunit from CFA/III. CofA is very similar in structure to V. cholerae TcpA but possesses a 10-amino-acid insertion that replaces part of the α2-helix with an irregular loop containing a 3(10)-helix. Homology modeling suggests a very similar structure for the Longus LngA pilin. A model for the CFA/III pilus filament was generated using the TCP electron microscopy reconstruction as a template. The unique 3(10)-helix insert fits perfectly within the gap between CofA globular domains. This insert, together with differences in surface-exposed residues, produces a filament that is smoother and more negatively charged than TCP. To explore the specificity of the type IV pilus assembly apparatus, CofA was expressed heterologously in V. cholerae by replacing the tcpA gene with that of cofA within the tcp operon. Although CofA was synthesized and processed by V. cholerae, no CFA/III filaments were detected, suggesting that the components of the type IVb pilus assembly system are highly specific to their pilin substrates.
Collapse
|
24
|
Abstract
Little is known about the colonization mechanisms of Aeromonas spp. Previous work has suggested that the type IV bundle-forming pilus (Bfp) is an aeromonad intestinal colonization factor. This study provides the first genetic characterization of this structure. To define the role of Bfp in Aeromonas veronii bv. Sobria adherence, a 22-kb locus encoding the bundle-forming pilus was isolated; this contained 17 pilus-related genes similar to the mannose-sensitive hemagglutinin (MSHA) of Vibrio cholerae. Reverse transcriptase PCR (RT-PCR) demonstrated that the locus had two major transcriptional units, mshI to mshF and mshB to mshQ. Transcriptional fusion experiments demonstrated the presence of two strong promoters upstream of mshI and mshB. The locus encoded four putative prepilin proteins, one of which (MshA) corresponded to the N-terminal sequence of the previously isolated major pilin protein. All the pilin genes were inactivated, mutation of each minor or major pilin gene greatly reduced the bacterium's ability to adhere and form biofilms, and complementation of each mutant in trans rescued this phenotype. Mutation of the major pilin MshA and MshB, a minor pilin, resulted in their loss. The position of the mshH gene is conserved within a number of bacteria, and we have shown it is not transcriptionally linked to the other msh genes; moreover, its mutation did not have a dramatic effect on either adhesion or biofilm formation. We conclude that the bundle-forming pilus is required for A. veronii bv. Sobria adherence and biofilm formation; furthermore, both the major and minor pilin proteins are essential for this process.
Collapse
|
25
|
Isidean SD, Riddle MS, Savarino SJ, Porter CK. A systematic review of ETEC epidemiology focusing on colonization factor and toxin expression. Vaccine 2011; 29:6167-78. [PMID: 21723899 DOI: 10.1016/j.vaccine.2011.06.084] [Citation(s) in RCA: 181] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 06/15/2011] [Accepted: 06/22/2011] [Indexed: 11/29/2022]
Affiliation(s)
- S D Isidean
- Enteric Diseases Department, Infectious Disease Directorate, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA
| | | | | | | |
Collapse
|
26
|
Longus, a type IV pilus of enterotoxigenic Escherichia coli, is involved in adherence to intestinal epithelial cells. J Bacteriol 2010; 192:2791-800. [PMID: 20348256 DOI: 10.1128/jb.01595-09] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is the leading bacterial cause of diarrhea in the developing world, as well as the most common cause of traveler's diarrhea. The main hallmarks of this type of bacteria are the expression of one or more enterotoxins and fimbriae used for attachment to host intestinal cells. Longus is a pilus produced by ETEC. These bacteria grown in pleuropneumonia-like organism (PPLO) broth at 37 degrees C and in 5% CO(2) produced longus, showing that the assembly and expression of the pili depend on growth conditions and composition of the medium. To explore the role of longus in the adherence to epithelial cells, quantitative and qualitative analyses were done, and similar levels of adherence were observed, with values of 111.44 x 10(4) CFU/ml in HT-29, 101.33 x 10(4) CFU/ml in Caco-2, and 107.11 x 10(4) CFU/ml in T84 cells. In addition, the E9034A Delta lngA strain showed a significant reduction in longus adherence of 32% in HT-29, 22.28% in Caco-2, and 21.68% in T84 cells compared to the wild-type strain. In experiments performed with nonintestinal cells (HeLa and HEp-2 cells), significant differences were not observed in adherence between E9034A and derivative strains. Interestingly, the E9034A and E9034A Delta lngA(pLngA) strains were 30 to 35% more adherent in intestinal cells than in nonintestinal cells. Twitching motility experiments were performed, showing that ETEC strains E9034A and E9034A Delta lngA(pLngA) had the capacity to form spreading zones while ETEC E9034A Delta lngA does not. In addition, our data suggest that longus from ETEC participates in the colonization of human colonic cells.
Collapse
|
27
|
Clavijo AP, Bai J, Gómez-Duarte OG. The Longus type IV pilus of enterotoxigenic Escherichia coli (ETEC) mediates bacterial self-aggregation and protection from antimicrobial agents. Microb Pathog 2010; 48:230-8. [PMID: 20227481 DOI: 10.1016/j.micpath.2010.03.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 02/26/2010] [Accepted: 03/04/2010] [Indexed: 11/24/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) strains are leading causes of childhood diarrhea in developing countries. ETEC pili and non-pili adherence factors designated colonization surface antigens (CSA) are believed to be important in the pathogenesis of diarrhea. Longus, a type IV pilus identified as the CSA(21), is expressed in up to one-third of ETEC strains, and share similarities to the toxin-coregulated pilus of Vibrio cholerae, and the bundle-forming pilus of enteropathogenic E. coli. To identify longus phenotype and possible function, a site-directed mutation of the lngA major subunit gene in the E9034A wild type ETEC strain was constructed. Lack of longus expression from the lngA mutant was demonstrated by immunoblot analysis and electron microscopy using specific anti-LngA antibody. Formation of self-aggregates by ETEC was shown to be dependent on longus expression as the lngA mutant or wild type grown under poor longus expression conditions was unable to express this phenotype. Longus-expressing ETEC were also associated with improved survival when exposed to antibacterial factors including lysozyme and antibiotics. This suggests that longus-mediated bacterial self-aggregates protect bacteria against antimicrobial environmental agents and may promote gut colonization.
Collapse
Affiliation(s)
- Andrea P Clavijo
- Division of Infectious Diseases, Department of Pediatrics, University of Iowa Children's Hospital, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | | | | |
Collapse
|
28
|
Distribution of the Escherichia coli common pilus among diverse strains of human enterotoxigenic E. coli. J Clin Microbiol 2009; 47:1781-4. [PMID: 19357209 DOI: 10.1128/jcm.00260-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Escherichia coli common pilus (ECP) is produced by commensal and pathogenic E. coli strains. This pilus is unrelated to any of the known colonization factors (CFs) of enterotoxigenic E. coli (ETEC). In this study, we investigated the distribution and production of ECP among a collection of 136 human CF-positive and CF-negative ETEC strains of different geographic origins. The major pilus subunit gene, ecpA, was found in 109 (80%) of these strains, suggesting that it is widely distributed among ETEC strains. Phenotypic analysis of a subset of 43 strains chosen randomly showed that 58% of them produced ECP independently of the presence or absence of CFs, a percentage even higher than that of the most prevalent CFs. These data suggest an important role for ECP in the biology of ETEC, particularly in CF-negative strains, and in human infection.
Collapse
|
29
|
Kulkarni R, Dhakal BK, Slechta ES, Kurtz Z, Mulvey MA, Thanassi DG. Roles of putative type II secretion and type IV pilus systems in the virulence of uropathogenic Escherichia coli. PLoS One 2009; 4:e4752. [PMID: 19270734 PMCID: PMC2649431 DOI: 10.1371/journal.pone.0004752] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 02/05/2009] [Indexed: 01/17/2023] Open
Abstract
Background Type II secretion systems (T2SS) and the evolutionarily related type IV pili (T4P) are important virulence determinants in many Gram-negative bacterial pathogens. However, the roles of T2SS and T4P in the virulence of extraintestinal pathogenic Escherichia coli have not been determined. Methodology/Principal Findings To investigate the functions of putative T2SS and T4P gene clusters present in the model uropathogenic E. coli (UPEC) strains UTI89 and CFT073, we deleted the secretin gene present in each cluster. The secretin forms a channel in the outer membrane that is essential for the function of T2S and T4P systems. We compared the secretin deletion mutants with their wild type counterparts using tissue culture assays and the CBA/J mouse model of ascending urinary tract infection. No deficiencies were observed with any of the mutants in adherence, invasion or replication in human bladder or kidney cell lines, but UTI89 ΔhofQ and UTI89 ΔgspD exhibited approximately 2-fold defects in fluxing out of bladder epithelial cells. In the mouse infection model, each of the knockout mutants was able to establish successful infections in the bladder and kidneys by day one post-infection. However, UTI89 ΔhofQ and a CFT073 ΔhofQ ΔyheF double mutant both exhibited defects in colonizing the kidneys by day seven post-infection. Conclusions/Significance Based on our results, we propose that the putative T4P and T2S systems are virulence determinants of UPEC important for persistence in the urinary tract, particularly in renal tissues.
Collapse
Affiliation(s)
- Ritwij Kulkarni
- Center for Infectious Diseases, Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Bijaya K. Dhakal
- Department of Pathology, Division of Cell Biology and Immunology, University of Utah, Salt Lake City, Utah, United States of America
| | - E. Susan Slechta
- Department of Pathology, Division of Cell Biology and Immunology, University of Utah, Salt Lake City, Utah, United States of America
| | - Zachary Kurtz
- Center for Infectious Diseases, Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Matthew A. Mulvey
- Department of Pathology, Division of Cell Biology and Immunology, University of Utah, Salt Lake City, Utah, United States of America
| | - David G. Thanassi
- Center for Infectious Diseases, Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
| |
Collapse
|
30
|
The type 4 pili of enterohemorrhagic Escherichia coli O157:H7 are multipurpose structures with pathogenic attributes. J Bacteriol 2008; 191:411-21. [PMID: 18952791 DOI: 10.1128/jb.01306-08] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 produces long bundles of polar type 4 pili (T4P) called HCP (for hemorrhagic coli pili) that form physical bridges between bacteria associating with human and animal epithelial cells. Here, we sought to further investigate whether HCP possessed other pathogenicity attributes associated with T4P production. Comparative studies performed with wild-type EHEC EDL933 and an isogenic hcpA mutant revealed that HCP play different roles in the biology of this organism. We found that in addition to promoting bacterial attachment to host cells, HCP mediate (i) invasion of epithelial cells, (ii) hemagglutination of rabbit erythrocytes, (iii) interbacterial connections conducive to biofilm formation, (iv) specific binding to host extracellular matrix proteins laminin and fibronectin but not collagen, and (v) twitching motility. Nonadherent laboratory E. coli strain HB101 complemented with hcpABC genes on plasmid pJX22, which specifies for HCP overproduction in EDL933, became hyperadherent and invasive and produced a thick biofilm, suggesting that the presence of HCP confers HB101(pJX22) new attributes otherwise not exhibited by HB101. Analogous to other bacteria in which T4P are involved in the pathogenesis of several infectious diseases, our data strongly suggest that HCP display multiple functions that may contribute to EHEC colonization of different hosts and to virulence, survival, and transmission of this food-borne pathogen.
Collapse
|
31
|
Xicohtencatl-Cortes J, Monteiro-Neto V, Ledesma MA, Jordan DM, Francetic O, Kaper JB, Puente JL, Girón JA. Intestinal adherence associated with type IV pili of enterohemorrhagic Escherichia coli O157:H7. J Clin Invest 2008; 117:3519-29. [PMID: 17948128 DOI: 10.1172/jci30727] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Accepted: 08/13/2007] [Indexed: 12/24/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes hemorrhagic colitis and hemolytic uremic syndrome (HUS) by colonizing the gut mucosa and producing Shiga toxins (Stx). The only factor clearly demonstrated to play a role in EHEC adherence to intestinal epithelial cells is intimin, which binds host cell integrins and nucleolin, as well as a receptor (Tir) that it injects into the host cell. Here we report that EHEC O157:H7 produces adhesive type IV pili, which we term hemorrhagic coli pilus (HCP), composed of a 19-kDa pilin subunit (HcpA) that is encoded by the hcpA chromosomal gene. HCP were observed as bundles of fibers greater than 10 microm in length that formed physical bridges between bacteria adhering to human and bovine host cells. Sera of HUS patients, but not healthy individuals, recognized HcpA, suggesting that the pili are produced in vivo during EHEC infections. Inactivation of the hcpA gene in EHEC EDL933 resulted in significantly reduced adherence to cultured human intestinal and bovine renal epithelial cells and to porcine and bovine gut explants. An escN mutant, which is unable to translocate Tir, adhered less than the hcpA mutant, suggesting that adherence mediated by intimin-Tir interactions is a prelude to HCP-mediated adherence. An hcpA and stx1,2 triple mutant and an hcpA mutant had similar levels of adherence to bovine and human epithelial cells while a stx1,2 double mutant had only a minor defect in adherence, indicating that HCP-mediated adherence and cytotoxicity are independent events. Our data establish that EHEC O157:H7 HCP are intestinal colonization factors that are likely to contribute to the pathogenic potential of this food-borne pathogen.
Collapse
|
32
|
Genetic diversity of the gene cluster encoding longus, a type IV pilus of enterotoxigenic Escherichia coli. J Bacteriol 2007; 189:9145-9. [PMID: 17951389 DOI: 10.1128/jb.00722-07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) strains produce a type IV pilus named Longus. We identified a 16-gene cluster involved in the biosynthesis of Longus that has 57 to 95% identity at the protein level to CFA/III, another type IV pilus of ETEC. Alleles of the Longus structural subunit gene lngA demonstrate a diversity of 12 to 19% at the protein level with strong positive selection for point replacements and horizontal transfer.
Collapse
|
33
|
Starks AM, Froehlich BJ, Jones TN, Scott JR. Assembly of CS1 pili: the role of specific residues of the major pilin, CooA. J Bacteriol 2006; 188:231-9. [PMID: 16352839 PMCID: PMC1317577 DOI: 10.1128/jb.188.1.231-239.2006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CS1 pili are important virulence factors of enterotoxigenic Escherichia coli strains associated with human diarrheal disease. They are the prototype for a family of pili that share extensive sequence similarity among their structural and assembly proteins. Only four linked genes, cooB, cooA, cooC, and cooD, are required to produce CS1 pili in E. coli K-12. To identify amino acids important for the function of the major pilin CooA, we used alanine substitution mutagenesis targeting conserved residues in the N and C termini of the protein. To test function, we examined cooA mutants for the ability to agglutinate bovine erythrocytes. Each hemagglutination-negative (HA(-)) cooA mutant was examined to identify its assembly pathway defect. CooA has been shown to be degraded in the absence of CooB (K. Voegele, H. Sakellaris, and J. R. Scott, Proc. Natl. Acad. Sci. USA 94:13257-13261, 1997). We found several HA(-) cooA mutants that produced no detectable CooA, suggesting that recognition by CooB is mediated by residues in both the N and C termini of CooA. In addition, we found that alanine substitution for some of the conserved residues in the C-terminal motif "AGxYxG(x(6))T," which is found in all subunits of this pilus family, had no effect on pilus formation. However, alanine substitution for some of the alternating hydrophobic residues within this motif prevented CooA from interacting with CooD, which serves as both the tip adhesin and nucleation protein for pilus formation. Thus, it appears that some, but not all, of the residues in both the N and C termini of CooA play a critical role in the intermolecular interactions of the major pilin with the other structural and assembly proteins. We anticipate that the results obtained here for CS1 pili in enterotoxigenic E. coli will help develop an understanding of the pilus assembly pathway used by CS1 family members in several important human pathogens.
Collapse
Affiliation(s)
- Angela M Starks
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | | | | |
Collapse
|
34
|
van Schaik EJ, Giltner CL, Audette GF, Keizer DW, Bautista DL, Slupsky CM, Sykes BD, Irvin RT. DNA binding: a novel function of Pseudomonas aeruginosa type IV pili. J Bacteriol 2005; 187:1455-64. [PMID: 15687210 PMCID: PMC545619 DOI: 10.1128/jb.187.4.1455-1464.2005] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa produces multifunctional, polar, filamentous appendages termed type IV pili. Type IV pili are involved in colonization during infection, twitching motility, biofilm formation, bacteriophage infection, and natural transformation. Electrostatic surface analysis of modeled pilus fibers generated from P. aeruginosa strain PAK, K122-4, and KB-7 pilin monomers suggested that a solvent-exposed band of positive charge may be a common feature of all type IV pili. Several functions of type IV pili, including natural transformation and biofilm formation, involve DNA. We investigated the ability of P. aeruginosa type IV pili to bind DNA. Purified PAK, K122-4, and KB-7 pili were observed to bind both bacterial plasmid and salmon sperm DNA in a concentration-dependent and saturable manner. PAK pili had the highest affinity for DNA, followed by K122-4 and KB-7 pili. DNA binding involved backbone interactions and preferential binding to pyrimidine residues even though there was no evidence of sequence-specific binding. Pilus-mediated DNA binding was a function of the intact pilus and thus required elements present in the quaternary structure. However, binding also involved the pilus tip as tip-specific, but not base-specific, antibodies inhibited DNA binding. The conservation of a Thr residue in all type IV pilin monomers examined to date, along with the electrostatic data, implies that DNA binding is a conserved function of type IV pili. Pilus-mediated DNA binding could be important for biofilm formation both in vivo during an infection and ex vivo on abiotic surfaces.
Collapse
Affiliation(s)
- Erin J van Schaik
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Abstract
Francisella tularensis is a highly infectious gram-negative bacterium with potential for use as a bioweapon. Analysis of the F. tularensis live vaccine strain (LVS) ultrastructure by electron microscopy revealed the presence of long, thin fibers, similar in appearance to type 4 pili. The highly virulent F. tularensis Schu S4 strain was found to contain type 4 pilus genes, and we confirmed that these genes are present and expressed in the LVS.
Collapse
Affiliation(s)
- Horacio Gil
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794-5120, USA
| | | | | |
Collapse
|
36
|
Craig L, Pique ME, Tainer JA. Type IV pilus structure and bacterial pathogenicity. Nat Rev Microbiol 2004; 2:363-78. [PMID: 15100690 DOI: 10.1038/nrmicro885] [Citation(s) in RCA: 556] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lisa Craig
- Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
| | | | | |
Collapse
|
37
|
Collyn F, Marceau M, Simonet M. Yersinia pseudotuberculosis harbors a type IV pilus gene cluster that contributes to pathogenicity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 529:89-95. [PMID: 12756734 DOI: 10.1007/0-306-48416-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Affiliation(s)
- François Collyn
- Equipe Mixte Inserm (E9919)-Université (JE2225)-Institut Pasteur de Lille, Institut de Biologie de Lille, 59021, Lille, France
| | | | | |
Collapse
|
38
|
Monteiro-Neto V, Bando SY, Moreira-Filho CA, Girón JA. Characterization of an outer membrane protein associated with haemagglutination and adhesive properties of enteroaggregative Escherichia coli O111:H12. Cell Microbiol 2003; 5:533-47. [PMID: 12864813 DOI: 10.1046/j.1462-5822.2003.00299.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Diarrhoeagenic Escherichia coli strains of serotype O111:H12 are characterized by their aggregative pattern of adherence on cultured epithelial cells and thus are considered enteroaggregative E. coli (EAEC). We have previously shown that these EAEC strains lack the genes encoding the aggregative fimbriae I and II described in other heterologous EAEC strains. In this paper, we show compelling data suggesting that a plasmid-encoded outer membrane 58 kDa protein termed aggregative protein 58 (Ap58) produced by EAEC O111:H12 strains, is associated with the adherence capabilities and haemagglutination of animal red blood cells. This conclusion is supported by several lines of evidence: (i) adherent O111:H12 strains are able to produce Ap58; (ii) non-adherent O111:H12 strains are unable to produce Ap58; (iii) antibodies raised against Ap58 inhibited adherence and haemagglutination of epithelial and bovine red blood cells, respectively; (iv) a non-adherent E. coli K-12 host strain containing the ap58 gene determinant on plasmid pVM15 displayed abundant adherence to cultured HEp-2 cells; and (v) the purified Ap58 bound specifically to HEp-2 and bovine red blood cells. Our findings indicate that the aggregative adherence in the O111:H12 strains may be also mediated by non-fimbrial adhesins. We believe our data contribute to the understanding of the adherence mechanisms of these organisms.
Collapse
Affiliation(s)
- Valerio Monteiro-Neto
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil
| | | | | | | |
Collapse
|
39
|
Mundy R, Pickard D, Wilson RK, Simmons CP, Dougan G, Frankel G. Identification of a novel type IV pilus gene cluster required for gastrointestinal colonization of Citrobacter rodentium. Mol Microbiol 2003; 48:795-809. [PMID: 12694622 DOI: 10.1046/j.1365-2958.2003.03470.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Citrobacter rodentium is used as an in vivo model system for clinically significant enteric pathogens such as enterohaemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). These pathogens all colonize the lumen side of the host gastrointestinal tract via attaching and effacing (A/E) lesion formation. In order to identify genes required for the colonization of A/E-forming pathogens, a library of signature-tagged transposon mutants of C. rodentium was constructed and screened in mice. Of the 576 mutants tested, 14 were attenuated in their ability to colonize the descending colon. Of these, eight mapped to the locus of enterocyte effacement (LEE), which is required for the formation of A/E lesions, underlying the importance of this mechanism for pathogenesis. Another mutant, P5H2, was found to have a transposon insertion in an open reading frame that has strong similarity to type IV pilus nucleotide-binding proteins. The region flanking the transposon insertion was sequenced, identifying a cluster of 12 genes that encode the first described pilus of C. rodentium (named colonization factor Citrobacter, CFC). The proteins encoded by cfc genes have identity to proteins of the type IV COF pilus of enterotoxigenic E. coli (ETEC), the toxin co-regulated pilus of Vibrio cholerae and the bundle-forming pilus of EPEC. A non-polar mutation in cfcI, complementation of this strain with wild-type cfcI and complementation of strain P5H2 with wild-type cfcH confirmed that these genes are required for colonization of the gastrointestinal tract by C. rodentium. Thus, CFC provides a convenient model to study type IV pilus-mediated pathogen-host interactions under physiological conditions in the natural colonic environment.
Collapse
Affiliation(s)
- Rosanna Mundy
- Centre for Molecular Microbiology and Infection, Department of Biological Sciences Flowers Building, Imperial College London, London SW7 2AZ, UK
| | | | | | | | | | | |
Collapse
|
40
|
Steinsland H, Valentiner-Branth P, Grewal HMS, Gaastra W, Mølbak K K, Sommerfelt H. Development and evaluation of genotypic assays for the detection and characterization of enterotoxigenic Escherichia coli. Diagn Microbiol Infect Dis 2003; 45:97-105. [PMID: 12614980 DOI: 10.1016/s0732-8893(02)00504-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We developed and evaluated a method to genotypically identify enterotoxigenic Escherichia coli (ETEC) and to characterize these organisms with respect to 18 of 21 known colonization factors (CFs). The method, which is based on polynucleotide DNA-DNA colony hybridization, includes a pooled toxin probe assay to identify ETEC, and individual probe assays to detect the enterotoxins STp, STh, and LT, and the CFs CFA/I, CS1-CS8, CS12-CS15, CS17-CS19, CS21, and CS22. We evaluated the pooled toxin probe assay during a cohort study of childhood diarrhea, and the individual probe assays against 33 reference strains and 92 clinical ETEC isolates. There was close to a complete agreement between the pooled toxin probe assay and the individual toxin probe assays, and between the individual CF probe assays and the corresponding phenotypic assays.
Collapse
Affiliation(s)
- Hans Steinsland
- Centre for International Health, University of Bergen, Norway.
| | | | | | | | | | | |
Collapse
|
41
|
Collyn F, Léty MA, Nair S, Escuyer V, Ben Younes A, Simonet M, Marceau M. Yersinia pseudotuberculosis harbors a type IV pilus gene cluster that contributes to pathogenicity. Infect Immun 2002; 70:6196-205. [PMID: 12379698 PMCID: PMC130390 DOI: 10.1128/iai.70.11.6196-6205.2002] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fimbriae have been shown to play an essential role in the adhesion of pathogenic gram-negative bacteria to host cells. In the enteroinvasive bacterium Yersinia pseudotuberculosis, we characterized a previously unknown 11-kb chromosomal locus involved in the synthesis of type IV pili. The locus consists of 11 open reading frames forming a polycistronic unit and encoding putative Pil proteins, PilLMNOPQRSUVW. When introduced into Escherichia coli, the Y. pseudotuberculosis operon reconstituted bundles of filaments at a pole on the bacterial surface, demonstrating that the pil locus was functional in a heterogenous genetic background. Environmental factors regulated transcription of the Y. pseudotuberculosis operon; in particular, temperature, osmolarity, and oxygen tension were critical cues. Deletion of the type IV pilus gene cluster was associated with a reduction of Y. pseudotuberculosis pathogenicity for mice infected orally. Forty-one percent of Y. pseudotuberculosis strains isolated from human or animal sources harbored the type IV pilus locus. Therefore, the pil locus of Y. pseudotuberculosis might constitute an "adaptation island," permitting the microorganism to colonize a vast reservoir.
Collapse
Affiliation(s)
- François Collyn
- Equipe Mixte Inserm (E9919)-Université (JE2225)-Institut Pasteur de Lille, Institut de Biologie de Lille, France
| | | | | | | | | | | | | |
Collapse
|
42
|
Nishimura LS, Girón JA, Nunes SL, Guth BEC. Prevalence of enterotoxigenic Escherichia coli strains harboring the longus pilus gene in Brazil. J Clin Microbiol 2002; 40:2606-8. [PMID: 12089285 PMCID: PMC120555 DOI: 10.1128/jcm.40.7.2606-2608.2002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The longus type IV pilus gene (lngA) was highly prevalent (32.8%) among Brazilian enterotoxigenic Escherichia coli strains producing both heat-labile and heat-stable enterotoxins and bearing the CFA/I, CS1CS3, or CS6 antigen. Furthermore, lngA was more often found in strains isolated from children with diarrhea than in strains isolated from children without diarrhea.
Collapse
Affiliation(s)
- Lucilia S Nishimura
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo Escola Paulista de Medicina, UNIFESP, São Paulo, Brazil
| | | | | | | |
Collapse
|
43
|
Pichel MG, Binsztein N, Qadri F, Girón JA. Type IV longus pilus of enterotoxigenic Escherichia coli: occurrence and association with toxin types and colonization factors among strains isolated in Argentina. J Clin Microbiol 2002; 40:694-7. [PMID: 11826000 PMCID: PMC153402 DOI: 10.1128/jcm.40.2.694-697.2002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The longus type IV pilus structural gene (lngA) was sought among 217 clinical enterotoxigenic Escherichia coli (ETEC) strains isolated in Argentina. lngA was present in 20.7% of the isolates and was highly associated with ETEC producing heat-stable toxin and the most common colonization factors. The prevalence of longus among ETEC strains in Argentina was comparable to that of colonization factor antigen I (CFA/I), CFA/II, and CFA/IV in other regions of the world.
Collapse
Affiliation(s)
- Mariana G Pichel
- Instituto Nacional de Enfermedades Infecciosas, ANLIS "Carlos G. Malbrán," Buenos Aires, Argentina
| | | | | | | |
Collapse
|
44
|
Park HS, Wolfgang M, van Putten JP, Dorward D, Hayes SF, Koomey M. Structural alterations in a type IV pilus subunit protein result in concurrent defects in multicellular behaviour and adherence to host tissue. Mol Microbiol 2001; 42:293-307. [PMID: 11703655 DOI: 10.1046/j.1365-2958.2001.02629.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ability of bacteria to establish complex communities on surfaces is believed to require both bacterial-substratum and bacterial-bacterial interactions, and type IV pili appear to play a critical but incompletely defined role in both these processes. Using the human pathogen Neisseria gonorrhoeae, spontaneous mutants defective in bacterial self-aggregative behaviour but quantitatively unaltered in pilus fibre expression were isolated by a unique selective scheme. The mutants, carrying single amino acid substitutions within the conserved amino-terminal domain of the pilus fibre subunit, were reduced in the ability to adhere to a human epithelial cell line. Co-expression of the altered alleles in the context of a wild-type pilE gene confirmed that they were dominant negative with respect to aggregation and human cell adherence. Strains expressing two copies of the altered alleles produced twice as much purifiable pili but retained the aggregative and adherence defects. Finally, the defects in aggregative behaviour and adherence of each of the mutants were suppressed by a loss-of-function mutation in the twitching motility gene pilT. The correlations between self-aggregation and the net capacity of the microbial population to adhere efficiently demonstrates the potential significance of bacterial cell-cell interactions to colonization.
Collapse
Affiliation(s)
- H S Park
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | | | | | | | | | | |
Collapse
|
45
|
Gutiérrez-Cázarez Z, Qadri F, Albert MJ, Girón JA. Identification of enterotoxigenic Escherichia coli harboring longus type IV pilus gene by DNA amplification. J Clin Microbiol 2000; 38:1767-71. [PMID: 10790096 PMCID: PMC86583 DOI: 10.1128/jcm.38.5.1767-1771.2000] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/1999] [Accepted: 02/11/2000] [Indexed: 11/20/2022] Open
Abstract
DNA amplification of lngA, the structural gene of longus type IV pilus produced by human enterotoxigenic Escherichia coli (ETEC) was achieved by the use of specific oligonucleotide primers designed from the nucleotide sequence of lngA. A 630-bp fragment representing the entire lngA gene was amplified in eight prototype strains previously characterized as longus positive. Five ETEC strains producing colonization factor antigen III (CFA III) (also a type IV pilus) were also positive by PCR, confirming the DNA homology between CFA III and longus. None of the non-ETEC and non-E. coli enteropathogens studied showed the 0.63-kbp amplicon. The procedure thus detected only ETEC strains harboring type IV pili genes with or without other colonization factors. Except for five lngA PCR-positive, probe-positive strains, all lngA PCR-positive strains produced the pilin as demonstrated by immunoblotting. To test the amplification procedure in a clinical setting, a collection of 264 fresh clinical E. coli strains isolated from 88 Mexican children with diarrhea was screened by PCR. Among 82 ETEC isolates found, 30 (36.5%) were lngA PCR-positive. Twenty-seven percent of the children shed ETEC that possessed lngA. In parallel with DNA probes or PCR protocols to detect enterotoxin genes, the lngA PCR method may prove useful for detection of ETEC harboring type IV pilus genes in epidemiological studies.
Collapse
Affiliation(s)
- Z Gutiérrez-Cázarez
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | | | | | | |
Collapse
|
46
|
McNamara BP, Donnenberg MS. Evidence for specificity in type 4 pilus biogenesis by enteropathogenic Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 3):719-729. [PMID: 10746776 DOI: 10.1099/00221287-146-3-719] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Type 4 fimbriae (pili) are surface appendages that are expressed by many species of Gram-negative bacteria. Previous studies have demonstrated that Pseudomonas aeruginosa can express and assemble pilin subunits from several unrelated species, indicating a common mechanism for biogenesis of type 4 pili whereby structural subunits from one system may be interchanged with those of another. In this study, an isogenic mutant of enteropathogenic Escherichia coli (EPEC) was constructed containing the entire tcpA gene from Vibrio cholerae 0395, which encodes the major structural subunit of the toxin-coregulated pilus (TCP), in place of bfpA, which encodes the major structural subunit of the bundle-forming pilus (BFP). Surprisingly, expression of type 4 pilin structures and the associated phenotype of bacterial autoaggregation in culture media were not observed for cells of the EPEC strain containing tcpA nor for those containing an additional mutation in bfpF, which otherwise is associated with a hyperfimbriate phenotype. In addition, cells of a bfpA mutant EPEC strain containing plasmids designed to express either of two different chimeric type 4 pilin subunits containing segments of BfpA and TcpA also failed to form bacterial aggregates and express type 4 pilin structures. Collectively, these results indicate that the type 4 pilin assembly system of EPEC exhibits specificity with regard to pilin subunit recognition and assembly.
Collapse
Affiliation(s)
- Barry P McNamara
- Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, 10 South Pine Street, Room 900, Baltimore, MD 21201, USA1
| | - Michael S Donnenberg
- Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, 10 South Pine Street, Room 900, Baltimore, MD 21201, USA1
| |
Collapse
|
47
|
Kirn TJ, Lafferty MJ, Sandoe CM, Taylor RK. Delineation of pilin domains required for bacterial association into microcolonies and intestinal colonization by Vibrio cholerae. Mol Microbiol 2000; 35:896-910. [PMID: 10692166 DOI: 10.1046/j.1365-2958.2000.01764.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The toxin-co-regulated pilus (TCP), a type 4 pilus that is expressed by epidemic strains of Vibrio cholerae O1 and O139, is required for colonization of the human intestine. The TCP structure is assembled as a polymer of repeating subunits of TcpA pilin that form long fibres, which laterally associate into bundles. Previous passive immunization studies have suggested that the C-terminal region of TcpA is exposed on the surface of the pilus fibre and has a critical role in mediating the colonization functions of TCP. In the present study, we have used site-directed mutagenesis to delineate two domains within the C-terminal region that contribute to TCP structure and function. Alterations in the first domain, termed the structural domain, result in altered pilus stability or morphology. Alterations in the second domain, termed the interaction domain, affect colonization and/or infection by CTX-bacteriophage without affecting pilus morphology. In vitro and in vivo analyses of the tcpA mutants revealed that a major function of TCP is to mediate bacterial interaction through direct pilus-pilus contact required for microcolony formation and productive intestinal colonization. The importance of this function is supported by the finding that intragenic suppressor mutations that restore colonization ability to colonization-deficient mutants simultaneously restore pilus-mediated bacterial interactions. The alterations resulting from the suppressor mutations also provide insight into the molecular interactions between pilin subunits within and between pilus fibres.
Collapse
Affiliation(s)
- T J Kirn
- Dartmouth Medical School, Department of Microbiology, Hanover, NH 03755, USA
| | | | | | | |
Collapse
|
48
|
Qadri F, Das SK, Faruque AS, Fuchs GJ, Albert MJ, Sack RB, Svennerholm AM. Prevalence of toxin types and colonization factors in enterotoxigenic Escherichia coli isolated during a 2-year period from diarrheal patients in Bangladesh. J Clin Microbiol 2000; 38:27-31. [PMID: 10618058 PMCID: PMC86010 DOI: 10.1128/jcm.38.1.27-31.2000] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The prevalence of toxin types and colonization factors (CFs) of enterotoxigenic Escherichia coli (ETEC) was prospectively studied with fresh samples (n = 4,662) obtained from a 2% routine surveillance of diarrheal stool samples over 2 years, from September 1996 to August 1998. Stool samples were tested by enzyme-linked immunoassay techniques and with specific monoclonal antibodies for the toxins and CFs. The prevalence of ETEC was 14% (n = 662), with over 70% of the strains isolated from children 0 to 5 years of age, of whom 93% were in the 0- to 3-year-old age range. Of the total ETEC isolates, 49.4% were positive for the heat-stable toxin (ST), 25.4% were positive for the heat-labile toxin (LT) only, and 25.2% were positive for both LT and ST. The rate of ETEC isolation peaked in the hot summer months of May to September and decreased in winter. About 56% of the samples were positive for 1 or more of the 12 CFs that were screened for. The coli surface antigens CS4, CS5, and/or CS6 of the colonization factor antigen (CFA)/IV complex were most prevalent (incidence, 31%), followed by CFA/I (23.5%) and coli surface antigens CS1, CS2, and CS3 of CFA/II (21%). In addition, other CFs detected in decreasing order were CS7 (8%), CS14 (PCFO166) (7%), CS12 (PCFO159) (4%), CS17 (3%), and CS8 (CFA/III) (2.7%). The ST- or LT- and ST-positive ETEC isolates expressed the CFs known to be the most prevalent (i.e., CFA/I, CFA/II, and CFA/IV), while the strains positive for LT only did not. Among children who were infected with ETEC as the single pathogen, a trend of relatively more severe disease in children infected with ST-positive (P < 0.001) or LT- and ST-positive (P < 0.001) ETEC isolates compared to the severity of the disease in children infected with LT only-positive ETEC isolates was seen. This study supports the fact that ETEC is still a major cause of childhood diarrhea in Bangladesh, especially in children up to 3 years of age, and that measures to prevent such infections are needed in developing countries.
Collapse
Affiliation(s)
- F Qadri
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka 1000, Bangladesh.
| | | | | | | | | | | | | |
Collapse
|
49
|
Taniguchi T, Yasuda Y, Tochikubo K, Yamamoto K, Honda T. The gene encoding the prepilin peptidase involved in biosynthesis of pilus colonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli. Microbiol Immunol 1999; 43:853-61. [PMID: 10553678 DOI: 10.1111/j.1348-0421.1999.tb01220.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The assembly of pilus colonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli requires the processing of CFA/III major pilin (CofA) by a peptidase, likely another type IV pilus formation system. Western blot analysis of CofA reveals that CofA is produced initially as a 26.5-kDa preform pilin (prepilin) and then processed to 20.5-kDa mature pilin by a prepilin peptidase. This processing is essential for exportation of the CofA from the cytoplasm to the periplasm. In this experiment, the structural gene, cofP, encoding CFA/III prepilin peptidase which cleavages at the Gly-30-Met-31 junction of CofA was identified, and the nucleotide sequence of the gene was determined. CofP consists of 819 bp encoding a 273-amino acid protein with a relative molecular mass of 30,533 Da. CofP is predicted to be localized in the inner membrane based on its hydropathy index. The amino acid sequence of CofP shows a high degree of homology with other prepilin peptidases which play a role in the assembly of type IV pili in several gram-negative bacteria.
Collapse
Affiliation(s)
- T Taniguchi
- Department of Microbiology, Nagoya City University Medical School, Nagoya, Aichi, Japan
| | | | | | | | | |
Collapse
|
50
|
Khalil SB, Cassels FJ, Shaheen HI, Pannell LK, El-Ghorab N, Kamal K, Mansour M, Savarino SJ, Peruski LF. Characterization of an enterotoxigenic Escherichia coli strain from Africa expressing a putative colonization factor. Infect Immun 1999; 67:4019-26. [PMID: 10417169 PMCID: PMC96691 DOI: 10.1128/iai.67.8.4019-4026.1999] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
An enterotoxigenic Escherichia coli (ETEC) strain of serotype O114:H- that expressed both heat-labile and heat-stable enterotoxins and tested negative for colonization factors (CF) was isolated from a child with diarrhea in Egypt. This strain, WS0115A, induced hemagglutination of bovine erythrocytes and adhered to the enterocyte-like cell line Caco-2, suggesting that it may elaborate novel fimbriae. Surface-expressed antigen purified by differential ammonium sulfate precipitation and column chromatography yielded a single protein band with M(r) 14,800 when resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (16% polyacrylamide). A monoclonal antibody against this putative fimbrial antigen was generated and reacted with strain WS0115A and also with CS1-, CS17-, and CS19-positive strains in a dot blot assay. Reactivity was temperature dependent, with cells displaying reactivity when grown at 37 degrees C but not when grown at 22 degrees C. Immunoblot analysis of a fimbrial preparation from strain WS0115A showed that the monoclonal antibody reacted with a single protein band. Electron microscopy and immunoelectron microscopy revealed fimbria-like structures on the surface of strain WS0115A. These structures were rigid and measured 6.8 to 7.4 nm in diameter. Electrospray mass-spectrometric analysis showed that the mass of the purified fimbria was 14,965 Da. The N-terminal sequence of the fimbria established that it was a member of the CFA/I family, with sequence identity to the amino terminus of CS19, a new CF recently identified in India. Cumulatively, our results suggest that this fimbria is CS19. Screening of a collection of ETEC strains isolated from children with diarrhea in Egypt found that 4.2% of strains originally reported as CF negative were positive for this CF, suggesting that it is biologically relevant in the pathogenesis of ETEC.
Collapse
Affiliation(s)
- S B Khalil
- Research Sciences Department, U.S. Naval Medical Research Unit No. 3, Cairo, Egypt
| | | | | | | | | | | | | | | | | |
Collapse
|