• Mechanisms of methods for hepatitis C virus inactivation.

      Pfaender, Stephanie; Brinkmann, Janine; Todt, Daniel; Riebesehl, Nina; Steinmann, Joerg; Steinmann, Jochen; Pietschmann, Thomas; Steinmann, Eike; Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research,Feodor-Lynen-Str. 7, 30625 Hannover, Germany. (2015-03-01)
      Virus inactivation by chemical disinfectants is an important instrument for infection control in medical settings, but the mechanisms involved are poorly understood. In this study, we systematically investigated the effects of several antiviral treatments on hepatitis C virus (HCV) particles as model for enveloped viruses. Studies were performed with authentic cell culture-derived viruses, and the influence of chemical disinfectants, heat, and UV treatment on HCV was analyzed by the determination of infectious particles in a limiting-dilution assay, by quantitative reverse transcription-PCR, by core enzyme-linked immunosorbent assay, and by proteolytic protection assay. All different inactivation methods resulted in a loss of HCV infectivity by targeting different parts of the virus particle. Alcohols such as ethanol and 2-propanol did not affect the viral RNA genome integrity but disrupted the viral envelope membrane in a capsid protection assay. Heat and UV treatment of HCV particles resulted in direct damage of the viral genome since transfection of viral particle-associated RNA into permissive cells did not initiate RNA replication. In addition, heat incubation at 80°C disrupted the HCV envelope, rendering the viral capsid susceptible to proteolytic digest. This study demonstrated the molecular processes of viral inactivation of an enveloped virus and should facilitate the development of effective disinfection strategies in infection control not only against HCV but also against other enveloped viruses.
    • Mutagenic Effects of Ribavirin on Hepatitis E Virus-Viral Extinction versus Selection of Fitness-Enhancing Mutations.

      Todt, Daniel; Walter, Stephanie; Brown, Richard J P; Steinmann, Eike; TWINCORE, Centre for experimental and clinical infection research GmbH, Feodor-Lynen Str. 7, 30625 Hannover, Germany. (2016-10-13)
      Hepatitis E virus (HEV), an important agent of viral hepatitis worldwide, can cause severe courses of infection in pregnant women and immunosuppressed patients. To date, HEV infections can only be treated with ribavirin (RBV). Major drawbacks of this therapy are that RBV is not approved for administration to pregnant women and that the virus can acquire mutations, which render the intra-host population less sensitive or even resistant to RBV. One of the proposed modes of action of RBV is a direct mutagenic effect on viral genomes, inducing mismatches and subsequent nucleotide substitutions. These transition events can drive the already error-prone viral replication beyond an error threshold, causing viral population extinction. In contrast, the expanded heterogeneous viral population can facilitate selection of mutant viruses with enhanced replication fitness. Emergence of these mutant viruses can lead to therapeutic failure. Consequently, the onset of RBV treatment in chronically HEV-infected individuals can result in two divergent outcomes: viral extinction versus selection of fitness-enhanced viruses. Following an overview of RNA viruses treated with RBV in clinics and a summary of the different antiviral modes of action of this drug, we focus on the mutagenic effect of RBV on HEV intrahost populations, and how HEV is able to overcome lethal mutagenesis.
    • The natural compound silvestrol inhibits hepatitis E virus (HEV) replication in vitro and in vivo.

      Todt, Daniel; Moeller, Nora; Praditya, Dimas; Kinast, Volker; Friesland, Martina; Engelmann, Michael; Verhoye, Lieven; Sayed, Ibrahim M; Behrendt, Patrick; Dao Thi, Viet Loan; et al. (2018-09-01)
      Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans and a member of the genus Orthohepevirus in the family Hepeviridae. HEV infections are the common cause of acute hepatitis but can also take chronic courses. Ribavirin is the treatment of choice for most patients and type I interferon (IFN) has been evaluated in a few infected transplantation patients in vivo. However, no effective and specific treatments against HEV infections are currently available. In this study, we evaluated the natural compound silvestrol, isolated from the plant Aglaia foveolata, and known for its specific inhibition of the DEAD-box RNA helicase eIF4A in state-of-the-art HEV experimental model systems. Silvestrol blocked HEV replication of different subgenomic replicons in a dose-dependent manner at low nanomolar concentrations and acted additive to ribavirin (RBV). In addition, HEV p6-based full length replication and production of infectious particles was reduced in the presence of silvestrol. A pangenotypic effect of the compound was further demonstrated with primary isolates from four different human genotypes in HEV infection experiments of hepatocyte-like cells derived from human embryonic and induced pluripotent stem cells. In vivo, HEV RNA levels rapidly declined in the feces of treated mice while no effect was observed in the vehicle treated control animals. In conclusion, silvestrol could be identified as pangenotypic HEV replication inhibitor in vitro with additive effect to RBV and further demonstrated high potency in vivo. The compound therefore may be considered in future treatment strategies of chronic hepatitis E in immunocompromised patients.
    • Natural reservoirs for homologs of hepatitis C virus.

      Pfaender, Stephanie; Brown, Richard Jp; Pietschmann, Thomas; Steinmann, Eike; Twincore Centre of Experimental and Clinical Infection Research; a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany. (2014-03)
      Hepatitis C virus is considered a major public health problem, infecting 2%-3% of the human population. Hepatitis C virus infection causes acute and chronic liver disease, including chronic hepatitis, cirrhosis and hepatocellular carcinoma. In fact, hepatitis C virus infection is the most frequent indication for liver transplantation and a vaccine is not available. Hepatitis C virus displays a narrow host species tropism, naturally infecting only humans, although chimpanzees are also susceptible to experimental infection. To date, there is no evidence for an animal reservoir of viruses closely related to hepatitis C virus which may have crossed the species barrier to cause disease in humans and resulted in the current pandemic. In fact, due to this restricted host range, a robust immunocompetent small animal model is still lacking, hampering mechanistic analysis of virus pathogenesis, immune control and prophylactic vaccine development. Recently, several studies discovered new viruses related to hepatitis C virus, belonging to the hepaci- and pegivirus genera, in small wild mammals (rodents and bats) and domesticated animals which live in close contact with humans (dogs and horses). Genetic and biological characterization of these newly discovered hepatitis C virus-like viruses infecting different mammals will contribute to our understanding of the origins of hepatitis C virus in humans and enhance our ability to study pathogenesis and immune responses using tractable animal models. In this review article, we start with an introduction on the genetic diversity of hepatitis C virus and then focus on the newly discovered viruses closely related to hepatitis C virus. Finally, we discuss possible theories about the origin of this important viral human pathogen.
    • Pentagalloylglucose, a highly bioavailable polyphenolic compound present in Cortex moutan, efficiently blocks hepatitis C virus entry.

      Behrendt, Patrick; Perin, Paula; Menzel, Nicolas; Branda, Dominic; Pfaender, Stephanie; Alves, Marco P.; Thiel, Volker; Meulemann, Philip; Colpit, Che C.; Schang, Luis M.; et al. (2017-01-01)
      Approximately 142 million people worldwide are infected with hepatitis C virus (HCV). Although potent direct acting antivirals are available, high costs limit access to treatment. Chronic hepatitis C virus infection remains a major cause of orthotopic liver transplantation. Moreover, re-infection of the graft occurs regularly. Antivirals derived from natural sources might be an alternative and cost-effective option to complement therapy regimens for global control of hepatitis C virus infection. We tested the antiviral properties of a mixture of different Chinese herbs/roots named Zhi Bai Di Huang Wan (ZBDHW) and its individual components on HCV. One of the ZBDHW components, Penta-O-Galloyl-Glucose (PGG), was further analyzed for its mode of action in vitro, its antiviral activity in primary human hepatocytes as well as for its bioavailability and hepatotoxicity in mice. ZBDHW, its component Cortex Moutan and the compound PGG efficiently block entry of HCV of all major genotypes and also of the related flavivirus Zika virus. PGG does not disrupt HCV virion integrity and acts primarily during virus attachment. PGG shows an additive effect when combined with the well characterized HCV inhibitor Daclatasvir. Analysis of bioavailability in mice revealed plasma levels above tissue culture IC
    • Prevalence and characterization of azole-resistant Aspergillus fumigatus in patients with cystic fibrosis: a prospective multicentre study in Germany.

      Seufert, R; Sedlacek, L; Kahl, B; Hogardt, M; Hamprecht, A; Haase, G; Gunzer, F; Haas, A; Grauling-Halama, S; MacKenzie, C R; et al. (2018-08-01)
      Aspergillus fumigatus is the most prevalent filamentous fungus in the respiratory tract of patients with cystic fibrosis (CF). The aim of this prospective multicentre study was to investigate the prevalence of azole-resistant A. fumigatus (ARAF) in respiratory secretions from CF patients across Germany and to characterize ARAF isolates by phenotypic and molecular methods. Twelve tertiary care centres from Germany participated in the study. In total, 2888 A. fumigatus isolates from 961 CF patients were screened for ARAF by using azole-containing agar plates. Antifungal susceptibility testing of isolates was performed by broth microdilution according to EUCAST guidelines. Analysis of mutations mediating resistance was performed using PCR and sequencing of the cyp51A gene. Furthermore, genotyping by microsatellite PCR was performed. Of a total of 2888 A. fumigatus isolates, 101 isolates from 51 CF patients were found to be azole resistant (prevalence per patient 5.3%). The Essen centre had the highest prevalence (9.1%) followed by Munich (7.8%), Münster (6.0%) and Hannover (5.2%). Most ARAF isolates (n = 89) carried the TR34/L98H mutation followed by eight G54E/R, one TR46/Y121F/T289A and one F219S mutation. In two isolates no mutation was found. Genotyping results showed no major clustering. Forty-five percent of CF patients with ARAF had previously received azole therapy. This is the first multicentre study analysing the prevalence of ARAF isolates in German CF patients. Because of a resistance rate of up to 9%, susceptibility testing of A. fumigatus isolates from CF patients receiving antifungal treatment should be part of standard diagnostic work-up.
    • Prevention strategies for blood-borne viruses-in the Era of vaccines, direct acting antivirals and antiretroviral therapy.

      Pfaender, Stephanie; von Hahn, Thomas; Steinmann, Joerg; Ciesek, Sandra; Steinmann, Eike; Twincore Centre of Experimental and Clinical Infection Research; a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany. (2016-09)
      Blood-borne viruses, such as hepatitis B virus, hepatitis C virus, human immunodeficiency virus, and the facultative blood-borne hepatitis E virus, are considered a major public health problem given that they are accountable for millions of deaths each year. Treatment options, including effective vaccine design, development of antiviral strategies and the implementation of antiretroviral therapy have improved substantially over the last couple of years and contribute to successful treatment and prevention of these infectious diseases. In this review, we summarise the current knowledge and concepts in prevention of transmission of these blood-borne viruses.
    • Six Heterocyclic Metabolites from the Myxobacterium Labilithrix luteola.

      Mulwa, Lucky S; Jansen, Rolf; Praditya, Dimas F; Mohr, Kathrin I; Wink, Joachim; Steinmann, Eike; Stadler, Marc; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2018-02-28)
      Two new secondary metabolites, labindole A [2-methyl-3-(2-nitroethyl)-3H-indole] (1) and labindole B [2-methyl-3-(2-nitrovinyl)-3H-indole] (2), were isolated from the myxobacteriumLabilithrixluteola(DSM 27648T). Additionally, four metabolites3,4,5and6already known from other sources were obtained. Their structures were elucidated from high resolution electrospray ionisation mass spectrometry (HRESIMS) and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy data and their relative configuration was assigned based on nuclear Overhauser effect (NOE) and vicinal ¹H-NMR coupling data. The compounds where tested for biological activities; labindoles A (1) and B (2) exhibited significant activity against Hepatitis C Virus, 9H-carbazole (3), 3-chloro-9H-carbazole (4) and 4-hydroxymethyl-quinoline (5) showed antifungal activities. Moreover, compound3had weak to moderate antibacterial activities, while labindoles A (1) and B (2) were devoid of significant antifungal and antibacterial effects.
    • Successful retreatment of a patient with chronic hepatitis C genotype 2k/1b virus with ombitasvir/paritaprevir/ritonavir plus dasabuvir.

      Todt, Daniel; Schlevogt, Bernhard; Deterding, Katja; Grundhoff, Adam; Manns, Michael P; Wedemeyer, Heiner; Fischer, Nicole; Cornberg, Markus; Steinmann, Eike; Twincore Centre of Experimental and Clinical Infection Research; a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany. (2017-01-18)
    • Susceptibility of Chikungunya Virus to Inactivation by Heat and Commercially and World Health Organization-Recommended Biocides.

      Franz, Sergej; Friesland, Martina; Passos, Vânia; Todt, Daniel; Simmons, Graham; Goffinet, Christine; Steinmann, Eike; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (Oxford University Press, 2018-09-22)
      Despite increasing clinical relevance of Chikungunya virus (CHIKV) infection, caused by a rapidly emerging pathogen, recommended guidelines for its inactivation do not exist. In this study, we investigated the susceptibility of CHIKV to inactivation by heat and commercially available hand, surface, and World Health Organization-recommended disinfectants to define CHIKV prevention protocols for healthcare systems.
    • Tracking HCV protease population diversity during transmission and susceptibility of founder populations to antiviral therapy.

      Khera, Tanvi; Todt, Daniel; Vercauteren, Koen; McClure, C Patrick; Verhoye, Lieven; Farhoudi, Ali; Bhuju, Sabin; Geffers, Robert; Baumert, Thomas F; Steinmann, Eike; et al. (2017-03)
      Due to the highly restricted species-tropism of Hepatitis C virus (HCV) a limited number of animal models exist for pre-clinical evaluation of vaccines and antiviral compounds. The human-liver chimeric mouse model allows heterologous challenge with clinically relevant strains derived from patients. However, to date, the transmission and longitudinal evolution of founder viral populations in this model have not been characterized in-depth using state-of-the-art sequencing technologies. Focusing on NS3 protease encoding region of the viral genome, mutant spectra in a donor inoculum and individual recipient mice were determined via Illumina sequencing and compared, to determine the effects of transmission on founder viral population complexity. In all transmissions, a genetic bottleneck was observed, although diverse viral populations were transmitted in each case. A low frequency cloud of mutations (<1%) was detectable in the donor inoculum and recipient mice, with single nucleotide variants (SNVs) > 1% restricted to a subset of nucleotides. The population of SNVs >1% was reduced upon transmission while the low frequency SNV cloud remained stable. Fixation of multiple identical synonymous substitutions was apparent in independent transmissions, and no evidence for reversion of T-cell epitopes was observed. In addition, susceptibility of founder populations to antiviral therapy was assessed. Animals were treated with protease inhibitor (PI) monotherapy to track resistance associated substitution (RAS) emergence. Longitudinal analyses revealed a decline in population diversity under therapy, with no detectable RAS >1% prior to therapy commencement. Despite inoculation from a common source and identical therapeutic regimens, unique RAS emergence profiles were identified in different hosts prior to and during therapeutic failure, with complex mutational signatures at protease residues 155, 156 and 168 detected. Together these analyses track viral population complexity at high-resolution in the human-liver chimeric mouse model post-transmission and under therapeutic intervention, revealing novel insights into the evolutionary processes which shape viral protease population composition at various critical stages of the viral life-cycle.
    • Two New Cyathane Diterpenoids from Mycelial Cultures of the Medicinal Mushroom Hericium erinaceus and the Rare Species, Hericium flagellum.

      Rupcic, Zeljka; Rascher, Monique; Kanaki, Sae; Köster, Reinhard W; Stadler, Marc; Wittstein, Kathrin; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2018-03-06)
      Basidiomycetes of the genusHericiumare among the most praised medicinal and edible mushrooms, which are known to produce secondary metabolites with the potential to treat neurodegenerative diseases. This activity has been attributed to the discovery of various terpenoids that can stimulate the production of nerve growth factor (NGF) or (as established more recently) brain-derived neurotrophic factor (BDNF) in cell-based bioassays. The present study reports on the metabolite profiles of a Lion's Mane mushroom (Hericium erinaceus) strain and a strain of the rare species,Hericium flagellum(synonymH. alpestre). While we observed highly similar metabolite profiles between the two strains that were examined, we isolated two previously undescribed metabolites, given the trivial names erinacines Z1 and Z2. Their chemical structures were elucidated by means of nuclear magnetic resonance (NMR) spectroscopy and high resolution mass spectrometry. Along with six further, previously identified cyathane diterpenes, the novel erinacines were tested for neurotrophin inducing effects. We found that erinacines act onBDNF, which is a neurotrophic factor that has been reported recently by us to be induced by the corallocins, but as well onNGFexpression, which is consistent with the literature.
    • Virucidal Activity of World Health Organization-Recommended Formulations Against Enveloped Viruses, Including Zika, Ebola, and Emerging Coronaviruses.

      Siddharta, Anindya; Pfaender, Stephanie; Vielle, Nathalie Jane; Dijkman, Ronald; Friesland, Martina; Becker, Britta; Yang, Jaewon; Engelmann, Michael; Todt, Daniel; Windisch, Marc P; et al. (2017-03-15)
      The World Health Organization (WHO) published 2 alcohol-based formulations to be used in healthcare settings and for outbreak-associated infections, but inactivation efficacies of these products have not been determined against (re-)emerging viruses. In this study, we evaluated the virucidal activity of these WHO products in a comparative analysis. Zika virus (ZIKV), Ebola virus (EBOV), severe acute respiratory syndrome coronavirus (SARS-CoV), and Middle East respiratory syndrome coronavirus (MERS-CoV) as (re-)emerging viral pathogens and other enveloped viruses could be efficiently inactivated by both WHO formulations, implicating their use in healthcare systems and viral outbreak situations.
    • Virucidal efficacy of a sonicated hydrogen peroxide system (trophon EPR) following European and German test methods.

      Becker, Britta; Bischoff, Birte; Brill, Florian H H; Steinmann, Eike; Steinmann, Jochen; TWINCORE, Zentrum für experimentelle und klinischeInfektionsforschung GmbH, Feodor-Lynen-Str. 7, 30625 Hannover, Germany. (2017-01-01)
      The virucidal efficacy of an automated ultrasound probe disinfector (trophon® EPR) was evaluated in a three step procedure according to European and German test methods. This system uses sonicated hydrogen peroxide mist (35%) at elevated temperature (50°C) in a closed chamber with control of all parameters within a 7 minute cycle. Methods: In the first step of examination, the peroxide solution was tested in a quantitative suspension assay according to the Guideline of Deutsche Vereinigung zur Bekämpfung der Viruskrankheiten (DVV) e.V. and Robert Koch-Institute (RKI) and in parallel with the European Norm EN 14476 with all test viruses creating a virucidal claim. In the second step, the virucidal efficacy of the hydrogen peroxide solution was evaluated in a hard surface carrier test according to the Guideline of DVV with adenovirus, murine norovirus and parvovirus simulating practical conditions. Finally, the efficacy was evaluated by the automated system using stainless steel carriers inoculated with test virus and positioned at different levels inside the chamber.
    • Virucidal efficacy of peracetic acid for instrument disinfection.

      Becker, Britta; Brill, Florian H H; Todt, Daniel; Steinmann, Eike; Lenz, Johannes; Paulmann, Dajana; Bischoff, Birte; Steinmann, Jochen; TwinCore, Zentrum für experimentelle und klinische Infektionsforschng GmbH, Feodor-Lynen-Str.7, 30625 Hannover, Germany. (2017)
      Various peracetic-acid (PAA)-based products for processing flexible endoscopes on the market are often based on a two-component system including a cleaning step before the addition of PAA as disinfectant. The peracetic acid concentrations in these formulations from different manufacturers are ranging from 400 to 1500 ppm (part per million). These products are used at temperatures between 20 °C and 37 °C. Since information on the virus-inactivating properties of peracetic acid at different concentrations and temperature is missing, it was the aim of the study to evaluate peracetic acid solutions against test viruses using the quantitative suspension test, EN 14476. In addition, further studies were performed with the recently established European pre norm (prEN 17111:2017) describing a carrier assay for simulating practical conditions using frosted glass.