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Wahl A, Fischer MA, Klaper K, Müller A, Borgmann S, Friesen J, Hunfeld KP, Ilmberger A, Kolbe-Busch S, Kresken M, Lippmann N, Lübbert C, Marschner M, Neumann B, Pfennigwerth N, Probst-Kepper M, Rödel J, Schulze MH, Zautner AE, Werner G, Pfeifer Y. Presence of hypervirulence-associated determinants in Klebsiella pneumoniae from hospitalised patients in Germany. Int J Med Microbiol 2024; 314:151601. [PMID: 38359735 DOI: 10.1016/j.ijmm.2024.151601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/15/2023] [Accepted: 01/15/2024] [Indexed: 02/17/2024] Open
Abstract
BACKGROUND Klebsiella (K.) pneumoniae is a ubiquitous Gram-negative bacterium and a common coloniser of animals and humans. Today, K. pneumoniae is one of the most persistent nosocomial pathogens worldwide and poses a severe threat/burden to public health by causing urinary tract infections, pneumonia and bloodstream infections. Infections mainly affect immunocompromised individuals and hospitalised patients. In recent years, a new type of K. pneumoniae has emerged associated with community-acquired infections such as pyogenic liver abscess in otherwise healthy individuals and is therefore termed hypervirulent K. pneumoniae (hvKp). The aim of this study was the characterisation of K. pneumoniae isolates with properties of hypervirulence from Germany. METHODS A set of 62 potentially hypervirulent K. pneumoniae isolates from human patients was compiled. Inclusion criteria were the presence of at least one determinant that has been previously associated with hypervirulence: (I) clinical manifestation, (II) a positive string test as a marker for hypermucoviscosity, and (III) presence of virulence associated genes rmpA and/or rmpA2 and/or magA. Phenotypic characterisation of the isolates included antimicrobial resistance testing by broth microdilution. Whole genome sequencing (WGS) was performed using Illumina® MiSeq/NextSeq to investigate the genetic repertoire such as multi-locus sequence types (ST), capsule types (K), further virulence associated genes and resistance genes of the collected isolates. For selected isolates long-read sequencing was applied and plasmid sequences with resistance and virulence determinants were compared. RESULTS WGS analyses confirmed presence of several signature genes for hvKp. Among them, the most prevalent were the siderophore loci iuc and ybt and the capsule regulator genes rmpA and rmpA2. The most dominant ST among the hvKp isolates were ST395 capsule type K2 and ST395 capsule type K5; both have been described previously and were confirmed by our data as multidrug-resistant (MDR) isolates. ST23 capsule type K1 was the second most abundant ST in this study; this ST has been described as commonly associated with hypervirulence. In general, resistance to beta-lactams caused by the production of extended-spectrum beta-lactamases (ESBL) and carbapenemases was observed frequently in our isolates, confirming the threatening rise of MDR-hvKp strains. CONCLUSIONS Our study results show that K. pneumoniae strains that carry several determinants of hypervirulence are present for many years in Germany. The detection of carbapenemase genes and hypervirulence associated genes on the same plasmid is highly problematic and requires intensified screening and molecular surveillance. However, the non-uniform definition of hvKp complicates their detection. Testing for hypermucoviscosity alone is not specific enough to identify hvKp. Thus, we suggest that the classification of hvKp should be applied to isolates that not only fulfil phenotypical criteria (severe clinical manifestations, hypermucoviscosity) but also (I) the presence of at least two virulence loci e.g. iuc and ybt, and (II) the presence of rmpA and/or rmpA2.
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Affiliation(s)
- Anika Wahl
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Martin A Fischer
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Kathleen Klaper
- Robert Koch Institute, Department of Sexually transmitted bacterial Pathogens (STI) and HIV, Berlin, Germany
| | - Annelie Müller
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Stefan Borgmann
- Klinikum Ingolstadt, Department of Infectious Diseases and Infection Control, Ingolstadt, Germany
| | | | - Klaus-Peter Hunfeld
- Institute for Laboratory Medicine, Microbiology & Infection Control, Northwest Medical Centre, Medical Faculty, Goethe University, Frankfurt am Main, Germany
| | | | - Susanne Kolbe-Busch
- Institute of Hygiene, Hospital Epidemiology and Environmental Medicine, Leipzig University Medical Center, Leipzig, Germany; Interdisciplinary Center for Infectious Diseases, Leipzig University Medical Center, Leipzig, Germany
| | - Michael Kresken
- Paul-Ehrlich-Gesellschaft für Infektionstherapie e. V., Cologne, Germany
| | - Norman Lippmann
- Institute for Medical Microbiology and Virology, University Hospital of Leipzig, Leipzig, Germany
| | - Christoph Lübbert
- Interdisciplinary Center for Infectious Diseases, Leipzig University Medical Center, Leipzig, Germany; Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Leipzig University Medical Center, Leipzig, Germany
| | | | - Bernd Neumann
- Institute of Clinical Microbiology, Infectious Diseases and Infection Control, Paracelsus Medical University, Nuremberg General Hospital, Nuremberg, Germany
| | - Niels Pfennigwerth
- German National Reference Centre for Multidrug-Resistant Gram-Negative Bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Bochum, Germany
| | | | - Jürgen Rödel
- Institute of Medical Microbiology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Marco H Schulze
- Department for Infection Control and Infectious Diseases, University Medical Center Goettingen, Goettingen, Germany
| | - Andreas E Zautner
- Institute of Medical Microbiology and Hospital Hygiene, Faculty of Medicine, Otto-von-Guericke-University, Magdeburg, Germany; Center for Health and Medical Prevention (CHaMP), Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Guido Werner
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany
| | - Yvonne Pfeifer
- Robert Koch Institute, Division of Infectious Diseases, Department of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode, Germany.
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Bates KA, Friesen J, Loyau A, Butler H, Vredenburg VT, Laufer J, Chatzinotas A, Schmeller DS. Environmental and Anthropogenic Factors Shape the Skin Bacterial Communities of a Semi-Arid Amphibian Species. Microb Ecol 2022:10.1007/s00248-022-02130-5. [PMID: 36445401 DOI: 10.1007/s00248-022-02130-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
The amphibian skin microbiome is important in maintaining host health, but is vulnerable to perturbation from changes in biotic and abiotic conditions. Anthropogenic habitat disturbance and emerging infectious diseases are both potential disrupters of the skin microbiome, in addition to being major drivers of amphibian decline globally. We investigated how host environment (hydrology, habitat disturbance), pathogen presence, and host biology (life stage) impact the skin microbiome of wild Dhofar toads (Duttaphrynus dhufarensis) in Oman. We detected ranavirus (but not Batrachochytrium dendrobatidis) across all sampling sites, constituting the first report of this pathogen in Oman, with reduced prevalence in disturbed sites. We show that skin microbiome beta diversity is driven by host life stage, water source, and habitat disturbance, but not ranavirus infection. Finally, although trends in bacterial diversity and differential abundance were evident in disturbed versus undisturbed sites, bacterial co-occurrence patterns determined through network analyses revealed high site specificity. Our results therefore provide support for amphibian skin microbiome diversity and taxa abundance being associated with habitat disturbance, with bacterial co-occurrence (and likely broader aspects of microbial community ecology) being largely site specific.
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Affiliation(s)
- K A Bates
- Department of Zoology, University of Oxford, Oxford, UK.
| | - J Friesen
- Centre for Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - A Loyau
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, INPT, UPS, Toulouse, France
| | - H Butler
- Department of Biology, San Francisco State University, San Francisco, CA, USA
| | - V T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, USA
| | - J Laufer
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - A Chatzinotas
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
- Institute of Biology, Leipzig University, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Leipzig, Germany
| | - D S Schmeller
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, INPT, UPS, Toulouse, France
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Freund T, Friesen J, Stolle JM, Kietzmann H, Neuber R, Müller M, Ignatius R. Rapid Tests for Detecting SARS-CoV-2-Specific Antigens. Dtsch Arztebl Int 2022; 119:647-648. [PMID: 36519345 PMCID: PMC9764349 DOI: 10.3238/arztebl.m2022.0292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 06/07/2022] [Accepted: 07/22/2022] [Indexed: 01/05/2023]
Affiliation(s)
| | | | | | | | | | | | - Ralf Ignatius
- Laboratory 28 Medical Center, Berlin ,Institute for Microbiology and Infection Immunology, Charité – University Medical Center Berlin
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4
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Puyskens A, Krause E, Michel J, Nübling CM, Scheiblauer H, Bourquain D, Grossegesse M, Valusenko R, Corman VM, Drosten C, Zwirglmaier K, Wölfel R, Lange C, Kramer J, Friesen J, Ignatius R, Müller M, Schmidt-Chanasit J, Emmerich P, Schaade L, Nitsche A. Establishment of a specimen panel for the decentralised technical evaluation of the sensitivity of 31 rapid diagnostic tests for SARS-CoV-2 antigen, Germany, September 2020 to April 2021. Euro Surveill 2021; 26:2100442. [PMID: 34738516 PMCID: PMC8569922 DOI: 10.2807/1560-7917.es.2021.26.44.2100442] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 09/10/2021] [Indexed: 12/23/2022] Open
Abstract
IntroductionThe detection of SARS-CoV-2 with rapid diagnostic tests (RDT) has become an important tool to identify infected people and break infection chains. These RDT are usually based on antigen detection in a lateral flow approach.AimWe aimed to establish a comprehensive specimen panel for the decentralised technical evaluation of SARS-CoV-2 antigen rapid diagnostic tests.MethodsWhile for PCR diagnostics the validation of a PCR assay is well established, there is no common validation strategy for antigen tests, including RDT. In this proof-of-principle study we present the establishment of a panel of 50 pooled clinical specimens that cover a SARS-CoV-2 concentration range from 1.1 × 109 to 420 genome copies per mL of specimen. The panel was used to evaluate 31 RDT in up to six laboratories.ResultsOur results show that there is considerable variation in the detection limits and the clinical sensitivity of different RDT. We show that the best RDT can be applied to reliably identify infectious individuals who present with SARS-CoV-2 loads down to 106 genome copies per mL of specimen. For the identification of infected individuals with SARS-CoV-2 loads corresponding to less than 106 genome copies per mL, only three RDT showed a clinical sensitivity of more than 60%.ConclusionsSensitive RDT can be applied to identify infectious individuals with high viral loads but not to identify all infected individuals.
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Affiliation(s)
- Andreas Puyskens
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
| | - Eva Krause
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
| | - Janine Michel
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
| | - C Micha Nübling
- Testing Laboratory for In-vitro Diagnostic Medical Devices, Paul-Ehrlich-Institute, Langen, Germany
| | - Heinrich Scheiblauer
- Testing Laboratory for In-vitro Diagnostic Medical Devices, Paul-Ehrlich-Institute, Langen, Germany
| | - Daniel Bourquain
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
| | - Marica Grossegesse
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
| | - Roman Valusenko
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
| | - Victor M Corman
- Charité - Universitätsmedizin Berlin, Institute of Virology and German Centre for Infection Research (DZIF), Associated Partner Site, Berlin, Germany
- Labor Berlin, Charité - Vivantes GmbH, Berlin, Germany
| | - Christian Drosten
- Charité - Universitätsmedizin Berlin, Institute of Virology and German Centre for Infection Research (DZIF), Associated Partner Site, Berlin, Germany
| | - Katrin Zwirglmaier
- Bundeswehr Institute of Microbiology and German Centre for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Roman Wölfel
- Bundeswehr Institute of Microbiology and German Centre for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Constanze Lange
- LADR Central Laboratory Dr. Kramer & Colleagues, Geesthacht, Germany
| | - Jan Kramer
- LADR Central Laboratory Dr. Kramer & Colleagues, Geesthacht, Germany
| | | | | | | | - Jonas Schmidt-Chanasit
- Bernhard Nocht Institute for Tropical Medicine, Arbovirology Department, Hamburg, Germany
| | - Petra Emmerich
- Bernhard Nocht Institute for Tropical Medicine, Arbovirology Department, Hamburg, Germany
- Department of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University of Rostock, Rostock, Germany
| | - Lars Schaade
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
| | - Andreas Nitsche
- Robert Koch Institute, Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, WHO Reference Laboratory for SARS-CoV-2 and WHO Collaborating Centre for Emerging Infections and Biological Threats, Robert Koch Institute, Berlin, Germany
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Hon C, Friesen J, Ingmundson A, Scheppan D, Hafalla JCR, Müller K, Matuschewski K. Conservation of S20 as an Ineffective and Disposable IFNγ-Inducing Determinant of Plasmodium Sporozoites Indicates Diversion of Cellular Immunity. Front Microbiol 2021; 12:703804. [PMID: 34421862 PMCID: PMC8377727 DOI: 10.3389/fmicb.2021.703804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/07/2021] [Indexed: 11/19/2022] Open
Abstract
Despite many decades of research to develop a malaria vaccine, only one vaccine candidate has been explored in pivotal phase III clinical trials. This candidate subunit vaccine consists of a portion of a single Plasmodium antigen, circumsporozoite protein (CSP). This antigen was initially identified in the murine malaria model and shown to contain an immunodominant and protective CD8+ T cell epitope specific to the H-2Kd (BALB/c)-restricted genetic background. A high-content screen for CD8+ epitopes in the H2Kb/Db (C57BL/6)-restricted genetic background, identified two distinct dominant epitopes. In this study, we present a characterization of one corresponding antigen, the Plasmodium sporozoite-specific protein S20. Plasmodium berghei S20 knockout sporozoites and liver stages developed normally in vitro and in vivo. This potent infectivity of s20(-) sporozoites permitted comparative analysis of knockout and wild-type parasites in cell-based vaccination. Protective immunity of irradiation-arrested s20(-) sporozoites in single, double and triple immunizations was similar to irradiated unaltered sporozoites in homologous challenge experiments. These findings demonstrate the presence of an immunogenic Plasmodium pre-erythrocytic determinant, which is not essential for eliciting protection. Although S20 is not needed for colonization of the mammalian host and for initiation of a blood infection, it is conserved amongst Plasmodium species. Malarial parasites express conserved, immunogenic proteins that are not required to establish infection but might play potential roles in diverting cellular immune responses.
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Affiliation(s)
- Calvin Hon
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
| | - Johannes Friesen
- Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany.,Medical Care Unit Labor 28 GmbH, Berlin, Germany
| | - Alyssa Ingmundson
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Diana Scheppan
- Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Julius C R Hafalla
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Katja Müller
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Kai Matuschewski
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
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6
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von Laer A, N'Guessan MA, Touré FS, Nowak K, Groeschner K, Ignatius R, Friesen J, Tomczyk S, Leendertz FH, Eckmanns T, Akoua-Koffi C. Implementation of Automated Blood Culture With Quality Assurance in a Resource-Limited Setting. Front Med (Lausanne) 2021; 8:627513. [PMID: 34095162 PMCID: PMC8176090 DOI: 10.3389/fmed.2021.627513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/23/2021] [Indexed: 11/21/2022] Open
Abstract
Background: Blood cultures (BC) have a high clinical relevance and are a priority specimen for surveillance of antimicrobial resistance. Manual BC are still most frequently used in resource-limited settings. Data on automated BC performance in Africa are scarce. We implemented automated BC at a surveillance site of the African Network for improved Diagnostics, Epidemiology and Management of Common Infectious Agents (ANDEMIA). Methods: Between June 2017 and January 2018, pairs of automated BC (BacT/ALERT®FA Plus) and manual BC (brain-heart infusion broth) were compared at a University hospital in Bouaké, Côte d'Ivoire. BC were inoculated each with a target blood volume of 10 ml from the same venipuncture. Automated BC were incubated for up to 5 days, manual BC for up to 10 days. Terminal subcultures were performed for manual BC only. The two systems were compared regarding yield, contamination, and turnaround time. For quality assurance, isolates were retested in a German routine microbiological laboratory. Results: BC sampling was increased from on average 24 BC to 63 BC per month. A total of 337 matched pairs of BC were included. Automated BC was positive in 36.5%, manual BC in 24.0% (p-value < 0.01), proportion of contamination was 47.9 and 43.8%, respectively (p-value = 1.0). Turnaround time of positive BC was shortened by 2.5 days with automated compared to manual BC (p < 0.01). Most common detected pathogens in both systems were Klebsiella spp. (26.0%) and Staphylococcus aureus (18.2%). Most contaminants were members of the skin flora. Retesting of 162 isolates was concordant in 79.6% on family level. Conclusions: Implementing automated BC in a resource-limited setting is possible and improves microbiological diagnostic performance. Automated BC increased yield and shortened turnaround times. Regular training and mentorship of clinicians has to be intensified to increase number and quality of BC. Pre-analytical training to improve diagnostic stewardship is essential when implementing a new microbiological method. Retesting highlighted that manual identification and antimicrobial susceptibility testing can be of good quality and sustainable. The implementation of automated tools should be decided individually according to economic considerations, number of samples, stable supply chain of consumables, and technical sustainability.
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Affiliation(s)
- Anja von Laer
- Postgraduate Training for Applied Epidemiology, Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany.,Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany.,European Programme for Intervention Epidemiology Training, European Centre for Disease Prevention and Control, Stockholm, Sweden
| | | | - Fidèle Sounan Touré
- Laboratoire Central, Centre Hospitalier et Universitaire de Bouaké, Bouaké, Côte d'Ivoire
| | - Kathrin Nowak
- Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Karin Groeschner
- Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Ralf Ignatius
- Department of Microbiology, Medical Care Unit Labor 28 GmbH, Berlin, Germany
| | - Johannes Friesen
- Department of Microbiology, Medical Care Unit Labor 28 GmbH, Berlin, Germany
| | - Sara Tomczyk
- Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Fabian H Leendertz
- Research Group Epidemiology of Highly Pathogenic Microorganisms, Robert Koch Institute, Berlin, Germany
| | - Tim Eckmanns
- Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Chantal Akoua-Koffi
- Laboratoire Central, Centre Hospitalier et Universitaire de Bouaké, Bouaké, Côte d'Ivoire
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7
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Liu T, Nadaraja AV, Friesen J, Gill K, Lam MI, Roberts DJ. Narrow pH tolerance found for a microbial fuel cell treating winery wastewater. J Appl Microbiol 2021; 131:2280-2293. [PMID: 33843137 DOI: 10.1111/jam.15102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/11/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
AIMS The use of microbial fuel cells (MFC) to treat winery wastewater is promising; however, an initial acidic pH, fluctuating chemical oxygen demand (COD) levels and a lack of natural buffering in these wastewaters make providing a suitable buffer system at an ideal buffer to COD ratio. METHODS AND RESULTS A lab scale MFC was designed, inoculated with anaerobic winery sludge and fed with synthetic winery wastewater. It was observed that at pH 6·5, the MFC performed best, the maximum output voltage was 0·63 ± 0·01 V for 60 ± 3 h, and the COD removal efficiency reached 77 ± 7%. The electrogens were affected by pH much more than the bulk COD degrading organisms. Fluorescent in situ hybridization suggested Betaproteobacteria played a significant role in electron transfer. CONCLUSIONS A ratio of 1 mmol l-1 phosphate buffer to 100 mg l-1 COD was ideal to maintain a stable pH for MFCs treating synthetic winery wastewater. SIGNIFICANCE AND IMPACT OF THE STUDY The results find the narrow pH tolerance for MFCs treating winery wastewater and demonstrate the significance of pH and buffer to COD ratio for steady performance of MFCs.
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Affiliation(s)
- T Liu
- School of Engineering, The University of British Columbia Okanagan, Kelowna, BC, Canada
| | - A V Nadaraja
- School of Engineering, The University of British Columbia Okanagan, Kelowna, BC, Canada
| | - J Friesen
- School of Engineering, The University of British Columbia Okanagan, Kelowna, BC, Canada
| | - K Gill
- School of Engineering, The University of British Columbia Okanagan, Kelowna, BC, Canada
| | - M I Lam
- School of Engineering, The University of British Columbia Okanagan, Kelowna, BC, Canada
| | - D J Roberts
- School of Engineering, The University of British Columbia Okanagan, Kelowna, BC, Canada.,Faculty of Science and Engineering, University of Northern British Columbia, Prince George, BC, Canada
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8
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Woschke A, Faber M, Stark K, Holtfreter M, Mockenhaupt F, Richter J, Regnath T, Sobottka I, Reiter-Owona I, Diefenbach A, Gosten-Heinrich P, Friesen J, Ignatius R, Aebischer T, Klotz C. Suitability of current typing procedures to identify epidemiologically linked human Giardia duodenalis isolates. PLoS Negl Trop Dis 2021; 15:e0009277. [PMID: 33764999 PMCID: PMC8023459 DOI: 10.1371/journal.pntd.0009277] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/06/2021] [Accepted: 02/26/2021] [Indexed: 12/26/2022] Open
Abstract
Background Giardia duodenalis is a leading cause of gastroenteritis worldwide. Humans are mainly infected by two different subtypes, i.e., assemblage A and B. Genotyping is hampered by allelic sequence heterozygosity (ASH) mainly in assemblage B, and by occurrence of mixed infections. Here we assessed the suitability of current genotyping protocols of G. duodenalis for epidemiological applications such as molecular tracing of transmission chains. Methodology/Principal findings Two G. duodenalis isolate collections, from an outpatient tropical medicine clinic and from several primary care laboratories, were characterized by assemblage-specific qPCR (TIF, CATH gene loci) and a common multi locus sequence typing (MLST; TPI, BG, GDH gene loci). Assemblage A isolates were further typed at additional loci (HCMP22547, CID1, RHP26, HCMP6372, DIS3, NEK15411). Of 175/202 (86.6%) patients the G. duodenalis assemblage could be identified: Assemblages A 25/175 (14.3%), B 115/175 (65.7%) and A+B mixed 35/175 (20.0%). By incorporating allelic sequence heterozygosity in the analysis, the three marker MLST correctly identified 6/9 (66,7%) and 4/5 (80.0%) consecutive samples from chronic assemblage B infections in the two collections, respectively, and identified a cluster of five independent patients carrying assemblage B parasites of identical MLST type. Extended MLST for assemblage A altogether identified 5/6 (83,3%) consecutive samples from chronic assemblage A infections and 15 novel genotypes. Based on the observed A+B mixed infections it is estimated that only 75% and 50% of assemblage A or B only cases represent single strain infections, respectively. We demonstrate that typing results are consistent with this prediction. Conclusions/Significance Typing of assemblage A and B isolates with resolution for epidemiological applications is possible but requires separate genotyping protocols. The high frequency of multiple infections and their impact on typing results are findings with immediate consequences for result interpretation in this field. Giardia duodenalis is a leading cause of gastroenteritis worldwide. Humans are mainly infected by the two different genetic subtypes, assemblage A and B. Molecular typing tools for epidemiological applications such as tracking transmission, attribution to a source and outbreak investigations have been developed and are highly desirable. However, to what degree the tetraploid genome with allelic sequence heterogeneity (ASH), and the frequent occurrence of mixed, assemblage A and B infections hamper performance is unclear. Here, we assessed the suitability of current genotyping protocols for deciphering the molecular epidemiology of G. duodenalis. Against a common reporting bias, we incorporated ASH in the analysis and we show that typing with resolution for epidemiological applications is possible for both, assemblage A and B isolates, but requires separate protocols. We also demonstrate how the high frequency of multiple infections overall impacts on typing results, which has immediate consequences for result interpretation in this field.
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Affiliation(s)
- Andreas Woschke
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
- Laboratory of Innate Immunity, Institute of Microbiology, Infectious Diseases and Immunology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
| | - Mirko Faber
- Department for Infectious Disease Epidemiology, Gastrointestinal Infections, Zoonoses and Tropical Infections Unit, Robert Koch Institute, Berlin, Germany
| | - Klaus Stark
- Department for Infectious Disease Epidemiology, Gastrointestinal Infections, Zoonoses and Tropical Infections Unit, Robert Koch Institute, Berlin, Germany
| | - Martha Holtfreter
- Department of Gastroenterology, Hepatology and Infectiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Frank Mockenhaupt
- Institute of Tropical Medicine and International Health, Charité University Medicine and Berlin Institute of Health, Corporate member of Free University Berlin and Humboldt University Berlin, Berlin, Germany
| | - Joachim Richter
- Department of Gastroenterology, Hepatology and Infectiology, University Hospital Düsseldorf, Düsseldorf, Germany
- Institute of Tropical Medicine and International Health, Charité University Medicine and Berlin Institute of Health, Corporate member of Free University Berlin and Humboldt University Berlin, Berlin, Germany
| | | | - Ingo Sobottka
- LADR GmbH, Medizinisches Versorgungszentrum, Geesthacht, Germany
| | - Ingrid Reiter-Owona
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Clinic Bonn, Germany
| | - Andreas Diefenbach
- Laboratory of Innate Immunity, Institute of Microbiology, Infectious Diseases and Immunology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
- Department of Microbiology and Hygiene, Labor Berlin, Charité - Vivantes GmbH, Berlin, Germany
| | - Petra Gosten-Heinrich
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | | | - Ralf Ignatius
- Laboratory of Innate Immunity, Institute of Microbiology, Infectious Diseases and Immunology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Benjamin Franklin, Berlin, Germany
- MVZ Labor 28, Berlin, Germany
| | - Toni Aebischer
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Christian Klotz
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
- * E-mail:
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Friesen J, Neuber R, Fuhrmann J, Kietzmann H, Wenzel T, Schaumburg F, Müller M, Ignatius R. Panton-Valentine leukocidin-positive Staphylococcus aureus in skin and soft tissue infections from primary care patients. Clin Microbiol Infect 2020; 26:1416.e1-1416.e4. [PMID: 32619735 DOI: 10.1016/j.cmi.2020.06.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 01/01/2023]
Abstract
OBJECTIVES To characterize deep skin and soft tissue infections (dSSTI) caused by Panton-Valentine leukocidin (PVL)-positive versus PVL-negative Staphylococcus aureus isolates. METHODS We performed a retrospective analysis of patients' records including S. aureus isolates from outpatients with dSSTI. Samples had been submitted by primary care physicians, i.e. general practitioners, surgeons, dermatologists and paediatricians, located in Berlin, Germany, in 2007-2017. Bacterial isolates were identified and tested for antimicrobial susceptibility by VITEK 2; PVL was detected by PCR. RESULTS In total, 1199 S. aureus isolates from 1074 patients with dSSTI were identified, and 613 (51.1%) of 1199 samples were PVL+. The median age of patients with PVL+S. aureus was lower than in patients with PVL- S. aureus (34 years, range 0-88 years, vs. 44 years, range 0-98 years; p < 0.0001). PVL was associated with repeated/multiple samples compared to single sample submission (69/92, 75% vs. 448/982, 45.6%, p < 0.0001; odds ratio (OR), 3.6; 95% confidence interval (CI), 2.2-5.8). Interestingly, the highest PVL positivity rate was found in isolates from gluteal (82/108, 75.9%; OR, 3.6; 95% CI, 2-5) or axillary (76/123, 61.8%; OR, 2; 95% CI, 1.1-3.3) localizations compared to isolates from the arm. The PVL positivity rate did not increase over time. Yet we noticed an increase in the trimethoprim/sulfamethoxazole (SXT) resistance rate in PVL+ isolates, mainly methicillin-sensitive S. aureus, when considering SXT resistance rates of 2007-2012 versus 2013-2017 (35/226, 15.5% vs. 74/289, 25.6%; p 0.01). CONCLUSIONS In outpatients, gluteal and axillary dSSTI are indicative of PVL+S. aureus. Providing SXT as a complementary treatment for dSSTI should be based on susceptibility testing.
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Affiliation(s)
| | | | | | | | | | - F Schaumburg
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | | | - R Ignatius
- MVZ Labor 28, Berlin, Germany; Institute of Microbiology and Infection Immunology, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany
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10
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Brückner V, Fiebiger U, Ignatius R, Friesen J, Eisenblätter M, Höck M, Alter T, Bereswill S, Gölz G, Heimesaat MM. Prevalence and antimicrobial susceptibility of Arcobacter species in human stool samples derived from out- and inpatients: the prospective German Arcobacter prevalence study Arcopath. Gut Pathog 2020; 12:21. [PMID: 32322308 PMCID: PMC7160977 DOI: 10.1186/s13099-020-00360-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/09/2020] [Indexed: 12/01/2022] Open
Abstract
Background Arcobacter species, particularly A. butzleri, but also A. cryaerophilus constitute emerging pathogens causing gastroenteritis in humans. However, isolation of Arcobacter may often fail during routine diagnostic procedures due to the lack of standard protocols. Furthermore, defined breakpoints for the interpretation of antimicrobial susceptibilities of Arcobacter are missing. Hence, reliable epidemiological data of human Arcobacter infections are scarce and lacking for Germany. We therefore performed a 13-month prospective Arcobacter prevalence study in German patients. Results A total of 4636 human stool samples was included and Arcobacter spp. were identified from 0.85% of specimens in 3884 outpatients and from 0.40% of specimens in 752 hospitalized patients. Overall, A. butzleri was the most prevalent species (n = 24; 67%), followed by A. cryaerophilus (n = 10; 28%) and A. lanthieri (n = 2; 6%). Whereas A. butzleri, A. cryaerophilus and A. lanthieri were identified in outpatients, only A. butzleri could be isolated from samples of hospitalized patients. Antimicrobial susceptibility testing of Arcobacter isolates revealed high susceptibilities to ciprofloxacin, whereas bimodal distributions of MICs were observed for azithromycin and ampicillin. Conclusions In summary, Arcobacter including A. butzleri, A. cryaerophilus and A. lanthieri could be isolated in 0.85% of German outpatients and ciprofloxacin rather than other antibiotics might be appropriate for antibiotic treatment of infections. Further epidemiological studies are needed, however, to provide a sufficient risk assessment of Arcobacter infections in humans.
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Affiliation(s)
- Vanessa Brückner
- 1Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Ulrike Fiebiger
- 2Institute of Microbiology, Infectious Diseases and Immunology, Charité- University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Ralf Ignatius
- 2Institute of Microbiology, Infectious Diseases and Immunology, Charité- University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.,Labor 28, Berlin, Germany
| | | | | | | | - Thomas Alter
- 1Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Stefan Bereswill
- 2Institute of Microbiology, Infectious Diseases and Immunology, Charité- University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Greta Gölz
- 1Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Markus M Heimesaat
- 2Institute of Microbiology, Infectious Diseases and Immunology, Charité- University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
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11
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Brückner V, Fiebiger U, Ignatius R, Friesen J, Eisenblätter M, Höck M, Alter T, Bereswill S, Heimesaat MM, Gölz G. Characterization of Arcobacter strains isolated from human stool samples: results from the prospective German prevalence study Arcopath. Gut Pathog 2020; 12:3. [PMID: 31921357 PMCID: PMC6947975 DOI: 10.1186/s13099-019-0344-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 12/23/2019] [Indexed: 02/03/2023] Open
Abstract
Background Arcobacter constitute emerging food- and waterborne pathogens causing gastroenteritis in humans, but the underlying mechanisms are only incompletely understood. We therefore characterized Arcobacter isolates derived from human stool samples that had been collected during a prospective prevalence study in Germany in vitro. Thirty-six bacterial isolates belonging to the species A. butzleri (n = 24), A. cryaerophilus (n = 10) and A. lanthieri (n = 2) were genotyped by ERIC-PCR, the presence of 10 putative virulence genes was assessed and cytotoxic effects on the human intestinal cell line HT-29/B6 were analyzed applying the WST-assay. Results Genotyping revealed high genetic diversity within the species A. butzleri, A. cryaerophilus and A. lanthieri. Both, A. butzleri and A. lanthieri encoded for a large number of putative virulence genes, while fewer genes were detectable in A. cryaerophilus isolates. Notably, the three cytolethal distending toxin (CDT) genes cdtA, cdtB and cdtC were abundant in both A. lanthieri isolates. Furthermore, all A. butzleri and A. lanthieri, but only one of the A. cryaerophilus isolates exerted cytotoxic effects. Conclusions Our study provides evidence for the abundance of putative virulence genes in Arcobacter isolates and prominent cytotoxic effects of A. butzleri and A. lanthieri in vitro. The presence of cdtA, cdtB, cdtC in A. lanthieri points towards CDT secretion as potential mechanism underlying cytotoxicity as opposed to A. butzleri. However, the association of the Arcobacter virulence factors detected and human morbidity should be addressed in future studies.
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Affiliation(s)
- Vanessa Brückner
- 1Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Ulrike Fiebiger
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ralf Ignatius
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Labor 28, Berlin, Germany
| | | | | | | | - Thomas Alter
- 1Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
| | - Stefan Bereswill
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Markus M Heimesaat
- Institute of Microbiology, Infectious Diseases and Immunology, Charité - University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Greta Gölz
- 1Institute of Food Safety and Food Hygiene, Freie Universität Berlin, Berlin, Germany
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12
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Friesen J, Bergmann C, Neuber R, Fuhrmann J, Wenzel T, Durst A, Müller M, Ignatius R. Detection of Enterobius vermicularis in greater Berlin, 2007-2017: seasonality and increased frequency of detection. Eur J Clin Microbiol Infect Dis 2019; 38:719-723. [PMID: 30712227 DOI: 10.1007/s10096-019-03495-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/22/2019] [Indexed: 11/30/2022]
Abstract
The pinworm (Enterobius vermicularis) causes mostly mild infections characterised by nocturnal anal pruritus, mainly in children. Still, the infection is stigmatising and sleep disturbances may lead to lack of concentration. For Germany, no epidemiological data are available. Laboratory data of all patients for whom detection of E. vermicularis by cellulose tape test had been requested between 2007 and November 2017 were analysed retrospectively. E. vermicularis was detected in 971/5578 (17.4%) samples collected from 3991 patients. The detection rate increased significantly within the period of investigation. It was higher in male than in female patients (20.0 vs. 15.4%). Children 4 to 10 years old and, if also examined, their relatives were most frequently affected. Control investigations at an interval of at least 1 month, which could indicate insufficient therapy or re-infection, were performed in 90/714 patients (12.6%). While parasite detection in children < 6 years was evenly distributed throughout the year, in older patients, it peaked between October and December. In conclusion, in the area of investigation, the frequency of E. vermicularis is higher in males than in females and is subject to a hitherto undescribed seasonality. The causes of the increased frequency of parasite detection warrant further investigations.
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Affiliation(s)
| | - Clara Bergmann
- Department of Microbiology and Infection Immunology, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200, Berlin, Germany
| | - Robert Neuber
- MVZ Labor 28, Mecklenburgische Str. 28, 14197, Berlin, Germany
| | - Jörg Fuhrmann
- MVZ Labor 28, Mecklenburgische Str. 28, 14197, Berlin, Germany
| | - Thilo Wenzel
- MVZ Labor 28, Mecklenburgische Str. 28, 14197, Berlin, Germany
| | - Anita Durst
- MVZ Labor 28, Mecklenburgische Str. 28, 14197, Berlin, Germany
| | - Michael Müller
- MVZ Labor 28, Mecklenburgische Str. 28, 14197, Berlin, Germany
| | - Ralf Ignatius
- MVZ Labor 28, Mecklenburgische Str. 28, 14197, Berlin, Germany. .,Department of Microbiology and Infection Immunology, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200, Berlin, Germany.
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13
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Friesen J, Fuhrmann J, Kietzmann H, Tannich E, Müller M, Ignatius R. Evaluation of the Roche LightMix Gastro parasites multiplex PCR assay detecting Giardia duodenalis, Entamoeba histolytica, cryptosporidia, Dientamoeba fragilis, and Blastocystis hominis. Clin Microbiol Infect 2018; 24:1333-1337. [DOI: 10.1016/j.cmi.2018.03.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 11/16/2022]
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Matuschewski K, Hafalla JC, Borrmann S, Friesen J. Arrested Plasmodium liver stages as experimental anti-malaria vaccines. Human Vaccines 2014; 7 Suppl:16-21. [DOI: 10.4161/hv.7.0.14557] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Hafalla JCR, Bauza K, Friesen J, Gonzalez-Aseguinolaza G, Hill AVS, Matuschewski K. Identification of targets of CD8⁺ T cell responses to malaria liver stages by genome-wide epitope profiling. PLoS Pathog 2013; 9:e1003303. [PMID: 23675294 PMCID: PMC3649980 DOI: 10.1371/journal.ppat.1003303] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 02/27/2013] [Indexed: 12/25/2022] Open
Abstract
CD8⁺ T cells mediate immunity against Plasmodium liver stages. However, the paucity of parasite-specific epitopes of CD8⁺ T cells has limited our current understanding of the mechanisms influencing the generation, maintenance and efficiency of these responses. To identify antigenic epitopes in a stringent murine malaria immunisation model, we performed a systematic profiling of H(2b)-restricted peptides predicted from genome-wide analysis. We describe the identification of Plasmodium berghei (Pb) sporozoite-specific gene 20 (S20)- and thrombospondin-related adhesive protein (TRAP)-derived peptides, termed PbS20₃₁₈ and PbTRAP₁₃₀ respectively, as targets of CD8⁺ T cells from C57BL/6 mice vaccinated by whole parasite strategies known to protect against sporozoite challenge. While both PbS20₃₁₈ and PbTRAP₁₃₀ elicit effector and effector memory phenotypes in both the spleens and livers of immunised mice, only PbTRAP₁₃₀-specific CD8⁺ T cells exhibit in vivo cytotoxicity. Moreover, PbTRAP₁₃₀-specific, but not PbS20₃₁₈-specific, CD8⁺ T cells significantly contribute to inhibition of parasite development. Prime/boost vaccination with PbTRAP demonstrates CD8⁺ T cell-dependent efficacy against sporozoite challenge. We conclude that PbTRAP is an immunodominant antigen during liver-stage infection. Together, our results underscore the presence of CD8⁺ T cells with divergent potencies against distinct Plasmodium liver-stage epitopes. Our identification of antigen-specific CD8⁺ T cells will allow interrogation of the development of immune responses against malaria liver stages.
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Affiliation(s)
- Julius Clemence R. Hafalla
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail: (JCRH); (KM)
| | - Karolis Bauza
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, United Kingdom
| | - Johannes Friesen
- Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Gloria Gonzalez-Aseguinolaza
- Department of Gene Therapy and Hepatology, Center for Investigation in Applied Medicine (CIMA), University of Navarra, Pamplona, Spain
| | - Adrian V. S. Hill
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, United Kingdom
| | - Kai Matuschewski
- Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
- Institute of Biology, Humboldt University, Berlin, Germany
- * E-mail: (JCRH); (KM)
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16
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Baumeister S, Wiesner J, Reichenberg A, Hintz M, Bietz S, Harb OS, Roos DS, Kordes M, Friesen J, Matuschewski K, Lingelbach K, Jomaa H, Seeber F. Fosmidomycin uptake into Plasmodium and Babesia-infected erythrocytes is facilitated by parasite-induced new permeability pathways. PLoS One 2011; 6:e19334. [PMID: 21573242 PMCID: PMC3087763 DOI: 10.1371/journal.pone.0019334] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 03/27/2011] [Indexed: 11/18/2022] Open
Abstract
Background Highly charged compounds typically suffer from low membrane permeability and thus are generally regarded as sub-optimal drug candidates. Nonetheless, the highly charged drug fosmidomycin and its more active methyl-derivative FR900098 have proven parasiticidal activity against erythrocytic stages of the malaria parasite Plasmodium falciparum. Both compounds target the isoprenoid biosynthesis pathway present in bacteria and plastid-bearing organisms, like apicomplexan parasites. Surprisingly, the compounds are inactive against a range of apicomplexans replicating in nucleated cells, including Toxoplasma gondii. Methodology/Principal Findings Since non-infected erythrocytes are impermeable for FR90098, we hypothesized that these drugs are taken up only by erythrocytes infected with Plasmodium. We provide evidence that radiolabeled FR900098 accumulates in theses cells as a consequence of parasite-induced new properties of the host cell, which coincide with an increased permeability of the erythrocyte membrane. Babesia divergens, a related parasite that also infects human erythrocytes and is also known to induce an increase in membrane permeability, displays a similar susceptibility and uptake behavior with regard to the drug. In contrast, Toxoplasma gondii-infected cells do apparently not take up the compounds, and the drugs are inactive against the liver stages of Plasmodium berghei, a mouse malaria parasite. Conclusions/Significance Our findings provide an explanation for the observed differences in activity of fosmidomycin and FR900098 against different Apicomplexa. These results have important implications for future screens aimed at finding new and safe molecular entities active against P. falciparum and related parasites. Our data provide further evidence that parasite-induced new permeability pathways may be exploited as routes for drug delivery.
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Affiliation(s)
- Stefan Baumeister
- Parasitologie, Fachbereich Biologie, Philipps-Universität, Marburg, Germany
| | - Jochen Wiesner
- Institut für Klinische Immunologie und Transfusionsmedizin, Universitätsklinikum Giessen und Marburg GmbH, Giessen, Germany
| | - Armin Reichenberg
- Institut für Klinische Immunologie und Transfusionsmedizin, Universitätsklinikum Giessen und Marburg GmbH, Giessen, Germany
| | - Martin Hintz
- Institut für Klinische Immunologie und Transfusionsmedizin, Universitätsklinikum Giessen und Marburg GmbH, Giessen, Germany
| | - Sven Bietz
- Parasitologie, Fachbereich Biologie, Philipps-Universität, Marburg, Germany
| | - Omar S. Harb
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - David S. Roos
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Maximilian Kordes
- Parasitology Unit, Max-Planck-Institute for Infection Biology, Berlin, Germany
| | - Johannes Friesen
- Parasitology Unit, Max-Planck-Institute for Infection Biology, Berlin, Germany
| | - Kai Matuschewski
- Parasitology Unit, Max-Planck-Institute for Infection Biology, Berlin, Germany
| | - Klaus Lingelbach
- Parasitologie, Fachbereich Biologie, Philipps-Universität, Marburg, Germany
| | - Hassan Jomaa
- Institut für Klinische Immunologie und Transfusionsmedizin, Universitätsklinikum Giessen und Marburg GmbH, Giessen, Germany
| | - Frank Seeber
- Parasitologie, Fachbereich Biologie, Philipps-Universität, Marburg, Germany
- Fachgebiet 16 Parasitologie, Robert-Koch-Institut, Berlin, Germany
- * E-mail:
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17
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Friesen J, Silvie O, Putrianti ED, Hafalla JCR, Matuschewski K, Borrmann S. Natural immunization against malaria: causal prophylaxis with antibiotics. Sci Transl Med 2010; 2:40ra49. [PMID: 20630856 DOI: 10.1126/scitranslmed.3001058] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Malaria remains the most prevalent vector-borne infectious disease and has the highest rates of fatality. Current antimalarial drug strategies cure malaria or prevent infections but lack a sustained public health impact because they fail to expedite the acquisition of protective immunity. We show that antibiotic administration during transmission of the parasite Plasmodium berghei results in swift acquisition of long-lived, life cycle-specific protection against reinfection with live sporozoites in mice. Antibiotic treatment specifically inhibits the biogenesis and inheritance of the apicoplast in Plasmodium liver stages, resulting in continued liver-stage maturation but subsequent failure to establish blood-stage infection. Exponential expansion of these attenuated liver-stage merozoites from a single sporozoite induces potent immune protection against malaria. If confirmed in residents of malaria-endemic areas, periodic prophylaxis with safe and affordable antibiotics may offer a powerful shortcut toward a needle-free surrogate malaria immunization strategy.
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Affiliation(s)
- Johannes Friesen
- Department of Infectious Diseases, Heidelberg University School of Medicine, 69120 Heidelberg, Germany
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Kranabetter JM, Friesen J, Gamiet S, Kroeger P. Epigeous fruiting bodies of ectomycorrhizal fungi as indicators of soil fertility and associated nitrogen status of boreal forests. Mycorrhiza 2009; 19:535-548. [PMID: 19449039 DOI: 10.1007/s00572-009-0255-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 04/27/2009] [Indexed: 05/27/2023]
Abstract
Soil fertility and associated nitrogen (N) status was a key ecosystem attribute, and surveys of ectomycorrhizal fungal (EMF) communities via epigeous fruiting bodies could provide an effective biotic indicator of forest soil productivity. We explored the utility of aboveground EMF communities in this regard by surveying sporocarps over a 3-year period from contrasting plant associations of southern old-growth boreal forests of British Columbia (Canada). Cumulative richness ranged from 39 to 89 EMF species per plot (0.15 ha) and followed a skewed parabolic correlation with foliar N concentrations and soil N availability. EMF species composition was consistently distinct in ordinations and strongly correlated to the increasing rates of N mineralization aligned with soil productivity. Approximately 40 EMF species were specialists, as they collectively indicated oligotrophic, mesotrophic, and eutrophic nutrient regimes, while the remaining species were categorized as broadly tolerant (distributed over 100% of the N gradient), partially intolerant (approximately 70%), or satellites (rare). The functional organization of EMF communities reflected by distribution classes could help define the ecological integrity of forests, which was characterized in this boreal landscape by an average allotment of 20 broadly tolerant, 25 partially intolerant, 15 specialist, and ten satellite species per plot. Epigeous fruiting bodies provided a disparate yet complementary view to the belowground assessment of EMF communities that was valuable in identifying indicators for ecosystem monitoring.
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Affiliation(s)
- J M Kranabetter
- British Columbia Ministry of Forests and Range, 4300 North Rd, Victoria, BC, Canada, V8Z 5J3.
| | - J Friesen
- Jodi Friesen Ecological Consulting, P.O. Box 15, Site F, Hazelton, BC, Canada, V0J 1Y0
| | - S Gamiet
- Mycology Resources, P.O. Box 2603, Clearbrook Station, Abbotsford, BC, Canada, V2T 6R4
| | - P Kroeger
- , 395 E 40th Ave, Vancouver, BC, Canada, V5W 1M1
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Saleh A, Friesen J, Baumeister S, Gross U, Bohne W. Growth inhibition of Toxoplasma gondii and Plasmodium falciparum by nanomolar concentrations of 1-hydroxy-2-dodecyl-4(1H)quinolone, a high-affinity inhibitor of alternative (type II) NADH dehydrogenases. Antimicrob Agents Chemother 2007; 51:1217-22. [PMID: 17242151 PMCID: PMC1855512 DOI: 10.1128/aac.00895-06] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Both apicomplexan parasites Toxoplasma gondii and Plasmodium falciparum lack type I NADH dehydrogenases (complex I) but instead carry alternative (type II) NADH dehydrogenases, which are absent in mammalian cells and are thus considered promising antimicrobial drug targets. The quinolone-like compound 1-hydroxy-2-dodecyl-4(1H)quinolone (HDQ) was recently described as a high-affinity inhibitor of fungal alternative NADH dehydrogenases in enzymatic assays, probably by interfering with the ubiquinol binding site of the enzyme. We describe here that HDQ effectively inhibits the replication rates of P. falciparum and T. gondii in tissue culture. The 50% inhibitory concentration (IC50) of HDQ for T. gondii was determined to be 2.4+/-0.3 nM with a growth assay based on vacuole sizes and 3.7+/-1.4 nM with a growth assay based on beta-galactosidase activity. Quantification of the P. falciparum replication rate using a fluorometric assay revealed an IC50 of 14.0+/-1.9 nM. An important feature of the HDQ structure is the length of the alkyl side chain at position 2. Derivatives with alkyl side chains of C6, C8, C12 (HDQ), and C14 all displayed excellent anti-T. gondii activity, while a C5 derivative completely failed to inhibit parasite replication. A combined treatment of T. gondii-infected cells with HDQ and the antimalarial agent atovaquone, which blocks the ubiquinol oxidation site of cytochrome b in complex III, resulted in synergism, with a calculated fractional inhibitory concentration of 0.16 nM. Interference of the mitochondrial ubiquinone/ubiquinol cycle at two different locations thus appears to be a highly effective strategy for inhibiting parasite replication. HDQ and its derivatives, particularly in combination with atovaquone, represent promising compounds with a high potential for antimalarial and antitoxoplasmal therapy.
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Affiliation(s)
- Ahmad Saleh
- Institute of Medical Microbiology, University of Göttingen, Kreuzbergring 57, D-37075 Göttingen, Germany
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Kranabetter JM, Friesen J. Ectomycorrhizal community structure on western hemlock (Tsuga heterophylla) seedlings transplanted from forests into openings. ACTA ACUST UNITED AC 2002. [DOI: 10.1139/b02-071] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study tested whether mature-forest ectomycorrhizal (ECM) communities could be maintained in forest openings on seedlings. Naturally regenerated western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were transplanted from mature forests into openings and the ECM fungal community was compared after 2 years with similar seedlings planted back into the forests or seedlings from openings planted back into openings. Fewer ECM morphotypes, lower average richness per seedling, and a steeper, less even species distribution curve were found, all of which suggest that the mature-forest ECM fungal community changed after transplanting forest seedlings into the openings. The increased abundance of pioneer fungi such as Thelephora terresteris suggested that many of the mature-forest ECM fungi were unable to maintain or continue root colonization in openings. Results suggest that many mature-forest ECM fungi require further stand development to maintain enough rooting density and hyphal contact to persist.Key words: ectomycorrhizal succession, disturbance, species-importance curves, multistage and late-stage fungi.
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Allende R, Kutish GF, Laegreid W, Lu Z, Lewis TL, Rock DL, Friesen J, Galeota JA, Doster AR, Osorio FA. Mutations in the genome of porcine reproductive and respiratory syndrome virus responsible for the attenuation phenotype. Arch Virol 2000; 145:1149-61. [PMID: 10948988 PMCID: PMC7086797 DOI: 10.1007/s007050070115] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although live-attenuated vaccines have been used for some time to control clinical symptoms of the porcine reproductive and respiratory syndrome (PRRS), the molecular bases for the attenuated phenotype remain unclear. We had previously determined the genomic sequence of the pathogenic PRRSV 16244B. Limited comparisons of the structural protein coding sequence of an attenuated vaccine strain have shown 98% homology to the pathogenic 16244B. Here we have confirmed the attenuated phenotype and determined the genomic sequence of that attenuated PRRSV vaccine and compared it to its parental VR-2332 and the 16244B strains. The attenuated vaccine sequence was colinear with that of the strain 16244B sequence containing no gaps and 212 substitutions over 15,374 determined nucleotide sequence. We identified nine amino acid changes distributed in Nsp1β, Nsp2, Nsp10, ORF2, ORF3, ORF5 and ORF6. These changes may provide the molecular bases for the observed attenuated phenotype.
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Affiliation(s)
- R Allende
- Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, 68583-0905, USA
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Colwill K, Field D, Moore L, Friesen J, Andrews B. In vivo analysis of the domains of yeast Rvs167p suggests Rvs167p function is mediated through multiple protein interactions. Genetics 1999; 152:881-93. [PMID: 10388809 PMCID: PMC1460664 DOI: 10.1093/genetics/152.3.881] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Morphological changes during cell division in the yeast Saccharomyces cerevisiae are controlled by cell-cycle regulators. The Pcl-Pho85p kinase complex has been implicated in the regulation of the actin cytoskeleton at least in part through Rvs167p. Rvs167p consists of three domains called BAR, GPA, and SH3. Using a two-hybrid assay, we demonstrated that each region of Rvs167p participates in protein-protein interactions: the BAR domain bound the BAR domain of another Rvs167p protein and that of Rvs161p, the GPA region bound Pcl2p, and the SH3 domain bound Abp1p. We identified Rvs167p as a Las17p/Bee1p-interacting protein in a two-hybrid screen and showed that Las17p/Bee1p bound the SH3 domain of Rvs167p. We tested the extent to which the Rvs167p protein domains rescued phenotypes associated with deletion of RVS167: salt sensitivity, random budding, and endocytosis and sporulation defects. The BAR domain was sufficient for full or partial rescue of all rvs167 mutant phenotypes tested but not required for the sporulation defect for which the SH3 domain was also sufficient. Overexpression of Rvs167p inhibits cell growth. The BAR domain was essential for this inhibition and the SH3 domain had only a minor effect. Rvs167p may link the cell cycle regulator Pcl-Pho85p kinase and the actin cytoskeleton. We propose that Rvs167p is activated by phosphorylation in its GPA region by the Pcl-Pho85p kinase. Upon activation, Rvs167p enters a multiprotein complex, making critical contacts in its BAR domain and redundant or minor contacts with its SH3 domain.
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Affiliation(s)
- K Colwill
- Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Ushinsky SC, Bussey H, Ahmed AA, Wang Y, Friesen J, Storms RK. Functional analysis of a 38 kilobase region on chromosome XVI in Saccharomyces cerevisiae. Genes Funct 1997; 1:273-84. [PMID: 9678903 DOI: 10.1046/j.1365-4624.1997.00025.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this report we assess the functional importance of 16 open reading frames (ORFs) contained within a 38 780 base-pair region immediately adjacent to the centromere on the right arm of chromosome XVI in Saccharomyces cerevisiae. This analysis involved replacing one copy of each ORF in a diploid strain with a cassette encoding the green fluorescent protein from the jellyfish Aequorea victoria and HIS3. Each replacement cassette was generated by PCR using oligonucleotide pairs with 45-base extensions complementary to sequences immediately upstream and downstream of the target gene's coding region. After replacement of the targeted genes, each gene-replacement strain was subjected to a series of genetic and phenotypic tests to assess the functional importance of the deleted gene. This analysis showed that two ORFs were essential, one for spores to germinate and another for vegetative growth. A third gene encoded a copper-fist-like transcription factor that was required for proper bud-site selection. One of the 16 ORFs was duplicated, a situation not observed in the strain used to sequence the yeast genome (S288C). RNA analysis showed 11 of the 16 ORFs in this region expressed steady-state poly(A+) RNA levels that were greater than or equal to 2% of the level expressed from the yeast actin gene, ACT1.
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Affiliation(s)
- S C Ushinsky
- Concordia University, Department of Biology, Montreal, Quebec, Canada
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Abstract
The existence of histone H1 in the yeast, Saccharomyces cerevisiae, has long been debated. In this report we describe the presence of histone H1 in yeast. YPL127c, a gene encoding a protein with a high degree of similarity to histone H1 from other species was sequenced as part of the contribution of the Montreal Yeast Genome Sequencing Group to chromosome XVI. To reflect this similarity, the gene designation has been changed HHO1 (Histone H One). The HHO1 gene is highly expressed as poly A+ RNA in yeast. Although deletion of this gene had no detectable effect on cell growth, viability or mating, it significantly altered the expression of beta-galactosidase from a CYC1-lacZ reporter. Fluorescence observed in cells expressing a histone H1-GFP protein fusion indicated that histone H1 is localized to the nucleus.
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Affiliation(s)
- S C Ushinsky
- Concordia University, Department of Biology, Montreal, Quebec, Canada
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Lopez MJ, Wong SK, Kishimoto I, Dubois S, Mach V, Friesen J, Garbers DL, Beuve A. Salt-resistant hypertension in mice lacking the guanylyl cyclase-A receptor for atrial natriuretic peptide. Nature 1995; 378:65-8. [PMID: 7477288 DOI: 10.1038/378065a0] [Citation(s) in RCA: 392] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Around half of all humans with essential hypertension are resistant to salt (blood pressure does not change by more than 5 mm Hg when salt intake is high), and although various inbred strains of rats display salt-insensitive elevated blood pressure, a gene defect to account for the phenotype has not been described. Atrial natriuretic peptide (ANP) is released from the heart in response to atrial stretch and is thought to mediate its natriuretic and vaso-relaxant effects through the guanylyl cyclase-A receptor (GC-A). Here we report that disruption of the GC-A gene results in chronic elevations of blood pressure in mice on a normal salt diet. Unexpectedly, the blood pressure remains elevated and unchanged in response to either minimal or high salt diets. Aldosterone and ANP concentrations are not affected by the genotype. Therefore, mutations in the GC-A gene could explain some salt-resistant forms of essential hypertension and, coupled with previous work, further suggest that the GC-A signaling pathway dominates at the level of peripheral resistance, where it can operate independently of ANP.
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Affiliation(s)
- M J Lopez
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas 75235-9050, USA
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Huang A, Friesen J, Brunton JL. Characterization of a bacteriophage that carries the genes for production of Shiga-like toxin 1 in Escherichia coli. J Bacteriol 1987; 169:4308-12. [PMID: 3040688 PMCID: PMC213745 DOI: 10.1128/jb.169.9.4308-4312.1987] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The Shiga-like toxin 1-converting bacteriophage H-19B was recently shown to carry the structural genes for the toxin and was shown to have DNA sequence homology with phage lambda. We present evidence that the linear genome of bacteriophage H-19B has cohesive termini which become covalently associated during prophage integration. Integration occurs through a site on a 4-kilobase-pair EcoRI fragment located near the center of the bacteriophage chromosome. The relationship between bacteriophages H-19B and lambda was examined by Southern hybridization. Homologous regions were mapped on the respective chromosomes which corresponded to the regions of the J gene, the int-xis area, and the O and P genes of phage lambda. The H-19B tox genes were mapped to the right of the O and P gene homology, which was far away from the phage attachment site. We concluded that H-19B is a lambdoid bacteriophage. Unlike other toxin-converting bacteriophages, the toxin genes were not located adjacent to the phage attachment site. It appeared that the Shiga-like toxin 1 genes were not picked up by a simple imprecise prophage excision. H-19B could, however, have acquired chromosomally located toxin genes by a series of events involving deletion and duplication followed by aberrant excision.
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De Grandis S, Ginsberg J, Toone M, Climie S, Friesen J, Brunton J. Nucleotide sequence and promoter mapping of the Escherichia coli Shiga-like toxin operon of bacteriophage H-19B. J Bacteriol 1987; 169:4313-9. [PMID: 3040689 PMCID: PMC213746 DOI: 10.1128/jb.169.9.4313-4319.1987] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We determined the nucleotide sequence of the Shiga-like toxin-1 (SLT-1) genes carried by the toxin-converting bacteriophage H-19B. Two open reading frames were identified; these were separated by 12 base pairs and encoded proteins of 315 (A subunit) and 89 (B subunit) amino acids. The predicted protein subunits had N-terminal hydrophobic signal sequences of 22 and 20 amino acids, respectively. The predicted amino acid sequence of the B subunit was identical to that of the B subunit of Shiga toxin. The A chain of ricin was found to be significantly related to the predicted A1 fragment of the SLT-1 A subunit. S1 nuclease protection experiments showed that the two cistrons formed a single transcriptional unit, with the A subunit being proximal to the promoter. A probable promoter was identified by primer extension, and transcription was found to increase dramatically under conditions of iron starvation. A 21-base-pair sequence with dyad symmetry was found in the region of the SLT-1 -10 sequence, which was found to be 68% homologous to a region of dyad symmetry found in the -35 region of the promoter of the iucA gene on plasmid ColV-K30, which specifies the 74,000-dalton ferric-aerobactin receptor protein. Betley et al. (M. Betley, V. Miller, and J. Mekalanos, Annu. Rev. Microbiol. 40:577-605, 1986) have recently summarized evidence suggesting that the slt operon is under the control of the fur regulatory system. The area of dyad symmetry found in both promoters may represent a regulatory site. A rho-independent terminator sequence was found 230 base pairs downstream from the B cistron stop codon.
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Huang A, de Grandis S, Friesen J, Karmali M, Petric M, Congi R, Brunton JL. Cloning and expression of the genes specifying Shiga-like toxin production in Escherichia coli H19. J Bacteriol 1986; 166:375-9. [PMID: 3009393 PMCID: PMC214614 DOI: 10.1128/jb.166.2.375-379.1986] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Some strains of Escherichia coli produce a protein which is cytotoxic for Vero cell and HeLa cell monolayers. This toxin is very similar to the toxin of Shigella dysenteriae 1 and has been named verotoxin or E. coli Shiga-like toxin. It has been shown that toxin conversion is due to a group of bacteriophages, one of which has been designated H-19B. In this study we report hybridization experiments showing that part of the H-19B genome is homologous to phage lambda. We have cloned a 1.7-kilobase BalI-BglII fragment from the genome of H-19B into pUC18. The recombinant plasmid confers the ability to produce high levels of Shiga-like toxin on transformed E. coli cells. We demonstrate using an in vitro transcription/translation system that the cloned fragment specifies the two verotoxin subunit peptides which have masses of 31 and 5.5 kilodaltons. The identity of peptides was confirmed by immunoprecipitation with verotoxin antiserum and protein A-Sepharose beads.
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Friesen J, Seery D, Speelman D, Tatpati OA. Experimental approach to diabetic obesity. J Kans Med Soc 1984; 85:234-5. [PMID: 6481208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Davies JA, Friesen J, McIntyre JD. A RADIOCHEMICAL TECHNIQUE FOR STUDYING RANGE–ENERGY RELATIONSHIPS FOR HEAVY IONS OF KEV ENERGIES IN ALUMINUM. CAN J CHEM 1960. [DOI: 10.1139/v60-213] [Citation(s) in RCA: 132] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A rapid technique has been developed for dissolving successive thin layers of metal from the surface of an aluminum foil: viz. electrochemical oxidation at constant voltage in aqueous ammonium citrate, followed by removal of the oxide film in a phosphoric acid – chromic oxide solution. Due to the highly protective nature of the aluminum oxide film, this two-step process enables very uniform surface layers of metal as thin as 1 μ/cm2 to be removed. The total weight of aluminum dissolved increases with the applied anodic voltage at a rate of 0.30 μg cm−1 volt−1 (approximately 11 Å per volt) over the range 0–150 volts. The technique should be sufficiently sensitive to study the depth of penetration in aluminum of radioactive ions with kinetic energies as low as a few kiloelectron volts.An approximate value for the range of Na24 recoil atoms from the Al27 (n,α) reaction was obtained. A more extensive application to range studies is given in the next paper.
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