TY - JOUR A1 - Biju, Joseph A1 - Schwarz, Roland A1 - Linke, Burkhard A1 - Blom, Jochen A1 - Becker, Anke A1 - Claus, Heike A1 - Goesmann, Alexander A1 - Frosch, Matthias A1 - Müller, Tobias A1 - Vogel, Ulrich A1 - Schoen, Christoph T1 - Virulence Evolution of the Human Pathogen Neisseria meningitidis by Recombination in the Core and Accessory Genome JF - PLoS One N2 - Background Neisseria meningitidis is a naturally transformable, facultative pathogen colonizing the human nasopharynx. Here, we analyze on a genome-wide level the impact of recombination on gene-complement diversity and virulence evolution in N. meningitidis. We combined comparative genome hybridization using microarrays (mCGH) and multilocus sequence typing (MLST) of 29 meningococcal isolates with computational comparison of a subset of seven meningococcal genome sequences. Principal Findings We found that lateral gene transfer of minimal mobile elements as well as prophages are major forces shaping meningococcal population structure. Extensive gene content comparison revealed novel associations of virulence with genetic elements besides the recently discovered meningococcal disease associated (MDA) island. In particular, we identified an association of virulence with a recently described canonical genomic island termed IHT-E and a differential distribution of genes encoding RTX toxin- and two-partner secretion systems among hyperinvasive and non-hyperinvasive lineages. By computationally screening also the core genome for signs of recombination, we provided evidence that about 40% of the meningococcal core genes are affected by recombination primarily within metabolic genes as well as genes involved in DNA replication and repair. By comparison with the results of previous mCGH studies, our data indicated that genetic structuring as revealed by mCGH is stable over time and highly similar for isolates from different geographic origins. Conclusions Recombination comprising lateral transfer of entire genes as well as homologous intragenic recombination has a profound impact on meningococcal population structure and genome composition. Our data support the hypothesis that meningococcal virulence is polygenic in nature and that differences in metabolism might contribute to virulence. KW - population genetics KW - DNA recombination KW - meningococcal disease KW - recombinant proteins KW - genomic databases KW - comparative genomics KW - neisseria meningitidis KW - homologous recombination Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137960 VL - 6 IS - 4 ER - TY - JOUR A1 - Schwerk, Christian A1 - Papandreou, Thalia A1 - Schuhmann, Daniel A1 - Nickol, Laura A1 - Borkowski, Julia A1 - Steinmann, Ulrike A1 - Quednau, Natascha A1 - Stump, Carolin A1 - Weiss, Christel A1 - Berger, Jürgen A1 - Wolburg, Hartwig A1 - Claus, Heike A1 - Vogel, Ulrich A1 - Ishikawa, Hiroshi A1 - Tenenbaum, Tobias A1 - Schroten, Horst T1 - Polar Invasion and Translocation of Neisseria meningitidis and Streptococcus suis in a Novel Human Model of the Blood-Cerebrospinal Fluid Barrier JF - PLoS One N2 - Acute bacterial meningitis is a life-threatening disease in humans. Discussed as entry sites for pathogens into the brain are the blood-brain and the blood-cerebrospinal fluid barrier (BCSFB). Although human brain microvascular endothelial cells (HBMEC) constitute a well established human in vitro model for the blood-brain barrier, until now no reliable human system presenting the BCSFB has been developed. Here, we describe for the first time a functional human BCSFB model based on human choroid plexus papilloma cells (HIBCPP), which display typical hallmarks of a BCSFB as the expression of junctional proteins and formation of tight junctions, a high electrical resistance and minimal levels of macromolecular flux when grown on transwell filters. Importantly, when challenged with the zoonotic pathogen Streptococcus suis or the human pathogenic bacterium Neisseria meningitidis the HIBCPP show polar bacterial invasion only from the physiologically relevant basolateral side. Meningococcal invasion is attenuated by the presence of a capsule and translocated N. meningitidis form microcolonies on the apical side of HIBCPP opposite of sites of entry. As a functionally relevant human model of the BCSFB the HIBCPP offer a wide range of options for analysis of disease-related mechanisms at the choroid plexus epithelium, especially involving human pathogens. KW - gene expression KW - plexus epithelial-cells KW - central-nervous-system KW - microvascular endothelial-cells KW - choroid-plexus KW - in vitro KW - brain barrier KW - tight junctions KW - meningococcal disease KW - bacterial meningitis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131459 VL - 7 IS - 1 ER - TY - JOUR A1 - Atanasov, Georgi A1 - Benkert, Christoph A1 - Thelen, Armin A1 - Tappe, Dennis A1 - Frosch, Matthias A1 - Teichmann, Dieter A1 - Barth, Thomas F. E. A1 - Wittekind, Christian A1 - Schubert, Stefan A1 - Jonas, Sven T1 - Alveolar echinococcosis-spreading disease challenging clinicians: A case report and literature review JF - World Journal of Gastroenterology N2 - Human alveolar echinococcosis (AE) is a potentially deadly disease; recent studies have shown that the endemic area of Echinococcus multilocularis, its causative agent, is larger than previously known. This disease has low prevalence and remains underreported in Europe. Emerging clinical data show that diagnostic difficulties are still common. We report on a 76-year old patient suffering from AE lesions restricted to the left lobe of the liver who underwent a curative extended left hemihepatectomy. Prior to the resection a liver biopsy under the suspicion of an atypical malignancy was performed. After the intervention he developed a pseudoaneurysm of the hepatic artery that was successfully coiled. Surprisingly, during surgery, the macroscopic appearance of the tumour revealed a growth pattern that was rather typical for cystic echinococcosis (CE), i.e., a gross tumour composed of multiple large vesicles with several centimeters in diameter. In addition, there were neither extensive adhesions nor infiltrations of the neighboring pancreas and diaphragm as was expected from previous imaging results. The unexpected diagnosis of AE was confirmed by definite histopathology, specific polymerase chain reaction and serology results. This is a rare case of unusual macroscopic presentation of AE that posed immense diagnostic challenges and had an eventful course. To our knowledge this is the first case of an autochthonous infection in this particular geographic area of Germany, the federal state of Saxony. This report may provide new hints for an expanding area of risk for AE and emphasizes the risk of complications in the scope of diagnostic procedures and the limitations of modern radiological imaging. KW - hemihepatectomy KW - multilocularis KW - Germany KW - Europe KW - liver KW - alveolar echinococcosis KW - echinococcus multilocularis KW - autochthonous infection KW - liver resection Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131525 VL - 19 IS - 26 ER - TY - JOUR A1 - Harrison, Odile B. A1 - Claus, Heike A1 - Jiang, Ying A1 - Bennett, Julia S. A1 - Bratcher, Holly B. A1 - Jolley, Keith A. A1 - Corton, Craig A1 - Care, Rory A1 - Poolman, Jan T. A1 - Zollinger, Wendell D. A1 - Frasch, Carl E. A1 - Stephens, David S. A1 - Feavers, Ian A1 - Frosch, Matthias A1 - Parkhill, Julian A1 - Vogel, Ulrich A1 - Quail, Michael A. A1 - Bentley, Stephen D. A1 - Maiden, Martin C. J. T1 - Description and Nomenclature of Neisseria meningitidis Capsule Locus JF - Emerging Infectious Diseases N2 - Pathogenic Neisseria meningitidis isolates contain a polysaccharide capsule that is the main virulence determinant for this bacterium. Thirteen capsular polysaccharides have been described, and nuclear magnetic resonance spectroscopy has enabled determination of the structure of capsular polysaccharides responsible for serogroup specificity. Molecular mechanisms involved in N. meningitidis capsule biosynthesis have also been identified, and genes involved in this process and in cell surface translocation are clustered at a single chromosomal locus termed cps. The use of multiple names for some of the genes involved in capsule synthesis, combined with the need for rapid diagnosis of serogroups commonly associated with invasive meningococcal disease, prompted a requirement for a consistent approach to the nomenclature of capsule genes. In this report, a comprehensive description of all N. meningitidis serogroups is provided, along with a proposed nomenclature, which was presented at the 2012 XVIIIth International Pathogenic Neisseria Conference. KW - genetics KW - nuclear magnetic resonance KW - structural determination KW - meningococcal polysaccharides KW - chemical properties KW - serogroup-Y KW - group-B KW - antigen KW - biosynthesis KW - elucidation Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131703 VL - 19 IS - 4 ER - TY - JOUR A1 - Marcus, U. A1 - Vogel, U. A1 - Schubert, A. A1 - Claus, H. A1 - Baetzing-Feigenbaum, J. A1 - Hellenbrand, W. A1 - Wichmann, O. T1 - A cluster of invasive meningococcal disease in young men who have sex with men in Berlin, October 2012 to May 2013 JF - Eurosurveillance N2 - No abstract available. KW - meningococcal disease Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131711 VL - 18 IS - 28 ER - TY - JOUR A1 - Moremi, Nyambura A1 - Mshana, Stephen E. A1 - Kamugisha, Erasmus A1 - Kataraihya, Johannes B. A1 - Tappe, Dennis A1 - Vogel, Ulrich A1 - Lyamuya, Eligius F. A1 - Claus, Heike T1 - Predominance of methicillin resistant Staphylococcus aureus-ST88 and new ST1797 causing wound infection and abscesses JF - Journal of Infection in Developing Countries N2 - Introduction: Although there has been a worldwide emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA), little is known about the molecular epidemiology of MRSA in Tanzania. Methodology: In this study, we characterized MRSA strains isolated from clinical specimens at the Bugando Medical Centre, Tanzania, between January and December 2008. Of 160 S. aureus isolates from 600 clinical specimens, 24 (15%) were found to be MRSA. Besides molecular screening for the Panton Valentine leukocidin (PVL) genes by PCR, MRSA strains were further characterized by Multi-Locus Sequence Typing (MLST) and spa typing. Results: Despite considerable genetic diversity, the spa types t690 (29.1%) and t7231 (41.6%), as well as the sequence types (ST) 88 (54.2%) and 1797 (29.1%), were dominant among clinical isolates. The PVL genes were detected in 4 isolates; of these, 3 were found in ST 88 and one in ST1820. Resistance to erythromycin, clindamicin, gentamicin, tetracycline and co-trimoxazole was found in 45.8%, 62.5%, 41.6%, 45.8% and 50% of the strains, respectively. Conclusion: We present the first thorough typing of MRSA at a Tanzanian hospital. Despite considerable genetic diversity, ST88 was dominant among clinical isolates at the Bugando Medical Centre. Active and standardized surveillance of nosocomial MRSA infection should be conducted in the future to analyse the infection and transmission rates and implement effective control measures. KW - Tanzania KW - panton-valentine leukocidin KW - field gel-electrophoreresis KW - molecular epidemiology KW - aureus infections KW - MRSA KW - ST88 KW - ST1797 Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134746 VL - 6 IS - 8 ER - TY - JOUR A1 - Nono, Justin Komguep A1 - Pletinckx, Katrien A1 - Lutz, Manfred B. A1 - Brehm, Klaus T1 - Excretory/Secretory-Products of Echinococcus multilocularis Larvae Induce Apoptosis and Tolerogenic Properties in Dendritic Cells In Vitro JF - PLoS Neglected Tropical Diseases N2 - Background: Alveolar echinococcosis, caused by Echinococcus multilocularis larvae, is a chronic disease associated with considerable modulation of the host immune response. Dendritic cells (DC) are key effectors in shaping the immune response and among the first cells encountered by the parasite during an infection. Although it is assumed that E. multilocularis, by excretory/secretory (E/S)-products, specifically affects DC to deviate immune responses, little information is available on the molecular nature of respective E/S-products and their mode of action. Methodology/Principal Findings: We established cultivation systems for exposing DC to live material from early (oncosphere), chronic (metacestode) and late (protoscolex) infectious stages. When co-incubated with Echinococcus primary cells, representing the invading oncosphere, or metacestode vesicles, a significant proportion of DC underwent apoptosis and the surviving DC failed to mature. In contrast, DC exposed to protoscoleces upregulated maturation markers and did not undergo apoptosis. After pre-incubation with primary cells and metacestode vesicles, DC showed a strongly impaired ability to be activated by the TLR ligand LPS, which was not observed in DC pre-treated with protoscolex E/S-products. While none of the larvae induced the secretion of pro-inflammatory IL-12p70, the production of immunosuppressive IL-10 was elevated in response to primary cell E/S-products. Finally, upon incubation with DC and naive T-cells, E/S-products from metacestode vesicles led to a significant expansion of Foxp3+ T cells in vitro. Conclusions: This is the first report on the induction of apoptosis in DC by cestode E/S-products. Our data indicate that the early infective stage of E. multilocularis is a strong inducer of tolerance in DC, which is most probably important for generating an immunosuppressive environment at an infection phase in which the parasite is highly vulnerable to host attacks. The induction of CD4+CD25+Foxp3+ T cells through metacestode E/S-products suggests that these cells fulfill an important role for parasite persistence during chronic echinococcosis. KW - granulosus KW - hydatid disease KW - metacestode vesicles KW - antigen-B KW - alveoar echinococcosis KW - TGF-BETA KW - regulatory T cells KW - gene expression KW - Brugia Malayi KW - TNF-alpha Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134280 VL - 6 IS - 2 ER - TY - JOUR A1 - Tappe, Dennis A1 - Haeupler, Alexandra A1 - Schäfer, Hansjörg A1 - Racz, Paul A1 - Cramer, Jakob P. A1 - Poppert, Sven T1 - Armillifer armillatus Pentastomiasis in African Immigrant, Germany JF - Emerging Infectious Diseases N2 - No abstract available. Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129054 N1 - Public Domain (Source: http://wwwnc.cdc.gov/eid/page/copyright-and-disclaimers) VL - 19 IS - 3 ER - TY - JOUR A1 - Fraunholz, Martin A1 - Bernhardt, Jörg A1 - Schuldes, Jörg A1 - Daniel, Rolf A1 - Hecker, Michael A1 - Sinh, Bhanu T1 - Complete Genome Sequence of Staphylococcus aureus 6850, a Highly Cytotoxic and Clinically Virulent Methicillin-Sensitive Strain with Distant Relatedness to Prototype Strains JF - Genome Announcements N2 - Staphylococcus aureus is a frequent human commensal bacterium and pathogen. Here we report the complete genome sequence of strain 6850 (spa type t185; sequence type 50 [ST50]), a highly cytotoxic and clinically virulent methicillin-sensitive strain from a patient with complicated S. aureus bacteremia associated with osteomyelitis and septic arthritis. KW - gen Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129294 VL - 1 IS - 5 ER - TY - THES A1 - Konrad, Christian T1 - Molecular analysis of insulin signaling mechanisms in Echinococcus multilocularis and their role in the host-parasite interaction in the alveolar echinococcosis T1 - Molekulare Analyse der Insulin-Signalmechanismen in Echinococcus multilocularis und ihre Rolle in der Wirt-Parasiten-Interaktion in der Alveolären Echinokokkose N2 - The insulin receptor ortholog EmIR of the fox-tapeworm Echinococcus multilocularis displays significant structural homology to the human insulin receptor (HIR) and has been suggested to be involved in insulin sensing mechanisms of the parasite’s metacestode larval stage. In the present work, the effects of host insulin on Echinococcus metacestode vesicles and the proposed interaction between EmIR and mammalian insulin have been studied using biochemical and cell-biological approaches. Human insulin, exogenously added to in vitro cultivated parasite larvae, (i) significantly stimulated parasite survival and growth, (ii) induced DNA de novo synthesis in Echinococcus, (iii) affected overall protein phosphorylation in the parasite, and (iv) specifically induced the phosphorylation of the parasite’s Erk-like MAP kinase orthologue EmMPK1. These results clearly indicated that Echinococcus metacestode vesicles are able to sense exogenous host insulin which induces a mitogenic response. To investigate whether EmIR mediates these effects, anti-EmIR antibodies were produced and utilized in biochemical assays and immunohistochemical analyses. EmIR was shown to be expressed in the germinal layer of the parasite both on the surface of glycogen storing cells and undifferentiated germinal cells. Upon addition of exogenous insulin to metacestode vesicles, the phosphorylation of EmIR was significantly induced, an effect which was suppressed in the presence of specific inhibitors of insulin receptor-like tyrosine kinases. Furthermore, upon expression of EmIR/HIR receptor chimera containing the extracellular ligand binding domain of EmIR in HEK 293 cells, a specific autophosphorylation of the chimera could be induced through the addition of exogenous insulin. These results indicated the capability of EmIR to sense and to transmit host insulin signals to the Echinococcus signaling machinery. The importance of insulin signaling mechanisms for parasite survival and growth were underscored by in vitro cultivation experiments in which the addition of an inhibitor of insulin receptor tyrosine kinases led to vesicle degradation and death. Based on the above outlined molecular data on the interaction between EmIR and mammalian insulin, the parasite’s insulin receptor orthologue most probably mediates the insulin effects on parasite growth and is, therefore, a potential candidate factor for host-parasite communication via evolutionary conserved pathways. In a final set of experiments, signaling mechanisms that act downstream of EmIR have been analyzed. These studies revealed significant differences between insulin signaling in Echinococcus and the related cestode parasite Taenia solium. These differences could be associated with differences in the organo-tropism of both species. N2 - Der orthologe Insulinrezeptor EmIR des Fuchsbandwurmes Echinococcus multilocularis weist signifikante strukturelle Homologie zum humanen Insulinrezeptor (HIR) auf. Es wurde schon seit geraumer Zeit vermutet, dass EmIR an den Mechanismen beteiligt sein könnte, die es dem Metacestoden Larvenstadium des Parasiten erlauben Insulin zu detektieren. In dieser Arbeit wurden die Effekte von Wirtsinsulin auf Echinococcus Metacestoden-Vesikel und die vermutete Interaktion zwischen EmIR und Insulin von Säugern mittels biochemischer und zellbiologischer experimenteller Ansätze untersucht. Die exogene Zugabe von humanem Insulin zu in vitro kultivierten Parasitenlarven hatte folgende Effekte: (i) das Überleben und das Wachstum des Parasiten wurde signifikant stimuliert; (ii) die DNA de novo Synthese in Echinococcus wurde induziert; (iii) die generelle Proteinphosphorylierung des Parasiten wurde beeinflusst; (iv) die Phosphorylierung der orthologen Erk-like MAP Kinase, EmMPK1, des Parasiten wurde spezifisch induziert. Diese Beobachtungen zeigen deutlich, dass Echinococcus Metacestoden-Vesikel exogenes Insulin des Wirtes detektieren können und dass dieses Insulin einen mitogenischen Effekt auf den Parasiten hat. Um zu untersuchen, ob diese Effekte durch EmIR vermittelt werden, wurden anti-EmIR Antikörper hergestellt und in biochemischen experimentellen Ansätzen und immunohistochemischen Analysen eingesetzt. Es konnte gezeigt werden, dass EmIR in der Germinalschicht des Parasiten expremiert wird, sowohl an der Oberfläche von Glykogen-Speicherzellen als auch von undifferenzierten Germinalzellen. Nach der Zugabe von exogenem Insulin konnte eine signifikante Zunahme der Phosphorylierung von EmIR festgestellt werden. Diese Stimulierung konnte durch die Zugabe eines spezifischen Inhibitors für Insulinrezeptor-ähnliche Tyrosinkinasen unterdrückt werden. Desweiteren konnte mittels der Expression eines chimären EmIR/HIR-Rezeptors, der die extrazelluläre Ligandenbindungsdomäne von EmIR enthielt, in HEK293 Zellen gezeigt werden, dass die Zugabe von exogenem Insulin eine spezifische Autophosphorylierung der Chimäre induziert. Diese Ergebnisse bezeugen die Fähigkeit von EmIR Insulin-abhängige Signale des Wirtes einerseits zu detektieren und andererseits an die Echinococcus Signalwege weiter zu leiten. Die Bedeutung von Insulin-Signalmechanismen für das Überleben und das Wachstum des Parasiten konnte durch in vitro Kultivierungsexperimente aufgezeigt werden. Die Zugabe eines Inhibitors spezifisch für Insulinrezeptor Tyrosinkinasen verursachte die Degradation und den Tod der Metacestoden-Vesikel. Basierend auf den dargelegten molekularen Daten bezüglich der Interaktion zwischen EmIR und Insulin von Säugern erscheint es sehr wahrscheinlich, dass der orthologe Insulinrezeptor des Parasiten die Effekte von Insulin auf das Wachstum des Parasiten vermittelt. Aus diesem Grund ist EmIR ein potentieller Kandidat für die Kommunikation zwischen Wirt und Parasiten mittels evolutionär konservierten Signalwegen. Die Signalmechanismen unterhalb von EmIR wurden in abschließenden Experimenten untersucht. Diese offenbarten deutliche Unterschiede in der Weiterleitung von Insulin induzierten Signalen zwischen Echinococcus und dem verwandten parasitären Zestoden Taenia solium. Diese Unterschiede könnten mit dem unterschiedlichen Organtropismus beider Arten in Verbindung stehen. KW - Fuchsbandwurm KW - Insulin KW - Echinokokkus KW - Insulin KW - Helminth KW - EmERK KW - Echinococcus KW - insulin KW - helminth KW - EmERK Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-22636 ER -