• Host-derived extracellular RNA promotes adhesion of Streptococcus pneumoniae to endothelial and epithelial cells.

      Zakrzewicz, Dariusz; Bergmann, Simone; Didiasova, Miroslava; Giaimo, Benedetto Daniele; Borggrefe, Tilman; Mieth, Maren; Hocke, Andreas C; Lochnit, Guenter; Schaefer, Liliana; Hammerschmidt, Sven; et al. (2016-11-28)
      Streptococcus pneumoniae is the most frequent cause of community-acquired pneumonia. The infection process involves bacterial cell surface receptors, which interact with host extracellular matrix components to facilitate colonization and dissemination of bacteria. Here, we investigated the role of host-derived extracellular RNA (eRNA) in the process of pneumococcal alveolar epithelial cell infection. Our study demonstrates that eRNA dose-dependently increased S. pneumoniae invasion of alveolar epithelial cells. Extracellular enolase (Eno), a plasminogen (Plg) receptor, was identified as a novel eRNA-binding protein on S. pneumoniae surface, and six Eno eRNA-binding sites including a C-terminal 15 amino acid motif containing lysine residue 434 were characterized. Although the substitution of lysine 434 for glycine (K434G) markedly diminished the binding of eRNA to Eno, the adherence to and internalization into alveolar epithelial cells of S. pneumoniae strain carrying the C-terminal lysine deletion and the mutation of internal Plg-binding motif were only marginally impaired. Accordingly, using a mass spectrometric approach, we identified seven novel eRNA-binding proteins in pneumococcal cell wall. Given the high number of eRNA-interacting proteins on pneumococci, treatment with RNase1 completely inhibited eRNA-mediated pneumococcal alveolar epithelial cell infection. Our data support further efforts to employ RNAse1 as an antimicrobial agent to combat pneumococcal infectious diseases.
    • Increased neutrophil extracellular trap-mediated Staphylococcus aureus clearance through inhibition of nuclease activity by clindamycin and immunoglobulin.

      Schilcher, Katrin; Andreoni, Federica; Uchiyama, Satoshi; Ogawa, Taiji; Schuepbach, Reto A; Zinkernagel, Annelies S; Helmholtz Centre for infection reseach, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2014-08-01)
      The Gram-positive human pathogen Staphylococcus aureus causes a variety of human diseases such as skin infections, pneumonia, and endocarditis. The micrococcal nuclease Nuc1 is one of the major S. aureus virulence factors and allows the bacterium to avoid neutrophil extracellular trap (NET)-mediated killing. We found that addition of the protein synthesis inhibitor clindamycin to S. aureus LAC cultures decreased nuc1 transcription and subsequently blunted nuclease activity in a molecular beacon-based fluorescence assay. We also observed reduced NET degradation through Nuc1 inhibition translating into increased NET-mediated clearance. Similarly, pooled human immunoglobulin specifically inhibited nuclease activity in a concentration-dependent manner. Inhibition of nuclease activity by clindamycin and immunoglobulin enhanced S. aureus clearance and should be considered in the treatment of S. aureus infections.
    • Genome sequence of the moderately thermophilic sulfur-reducing bacterium Thermanaerovibrio velox type strain (Z-9701T) and emended description of the genus Thermanaerovibrio

      Palaniappan, Krishna; Meier-Kolthoff, Jan P.; Teshima, Hazuki; Nolan, Matt; Lapidus, Alla; Tice, Hope; Del Rio, Tijana Glavina; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; et al. (2014-01-06)
    • The M1 protein of Streptococcus pyogenes triggers an innate uptake mechanism into polarized human endothelial cells.

      Ochel, Anja; Rohde, Manfred; Chhatwal, Gursharan S; Talay, Susanne R; Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweíg, Germany. (2014)
      Serotype M1 Streptococcus pyogenes is a major human pathogen associated with severe invasive diseases causing high morbidity and mortality. In a substantial number of cases, invasive disease develops in previously healthy individuals with no obvious port of entry. This has led to the hypothesis that the source of streptococci in these cases is a transient bacteraemia. This study focuses on the analysis of interaction of tissue-invasive serotype M1 S. pyogenes with human endothelial cells (EC) of the vascular system. We identify the M1 surface protein of S. pyogenes as the EC invasin which is recognised by polarized human blood EC, thereby triggering rapid, phagocytosis-like uptake of streptococci into polarized EC layers. Upon internalization, the M1 S. pyogenes serotype is incorporated into phagosomes which traffic via the endosomal/lysosomal pathway. However, some of the streptococci successfully evade this innate killing process and hereby mediate their escape into the cytoplasm of the host cell. The results of this study demonstrate that blood EC possess an efficient uptake mechanism for serotype M1 S. pyogenes. Despite efficient phagocytosis, streptococcal survival within EC constitutes one potential mechanism which favours intracellular persistence and thus facilitates continuous infection and dissemination from the primary side of infection into deep tissue.
    • Highly stable monodisperse PEGylated iron oxide nanoparticle aqueous suspensions: a nontoxic tracer for homogeneous magnetic bioassays.

      Lak, Aidin; Dieckhoff, Jan; Ludwig, Frank; Scholtyssek, Jan M; Goldmann, Oliver; Lünsdorf, Heinrich; Eberbeck, Dietmar; Kornowski, Andreas; Kraken, Mathias; Litterst, F J; et al. (2013-11-07)
      Uniformly sized and shaped iron oxide nanoparticles with a mean size of 25 nm were synthesized via decomposition of iron-oleate. High resolution transmission electron microscopy and Mössbauer spectroscopy investigations revealed that the particles are spheres primarily composed of Fe3O4 with a small fraction of FeO. From Mössbauer and static magnetization measurements, it was deduced that the particles are superparamagnetic at room temperature. The hydrophobic particles were successfully transferred into water via PEGylation using nitrodopamine as an anchoring group. IR spectroscopy and thermogravimetric analysis showed the success and efficiency of the phase transfer reaction. After PEGylation, the particles retained monodispersity and their magnetic core remained intact as proven by photon cross-correlation spectroscopy, ac susceptibility, and transmission electron microscopy. The particle aqueous suspensions revealed excellent water stability over a month of monitoring and also against temperature up to 40 °C. The particles exhibited a moderate cytotoxic effect on in vitro cultured bone marrow-derived macrophages and no release of inflammatory or anti-inflammatory cytokines. The PEGylated particles were functionalized with Herceptin antibodies via a conjugation chemistry, their response to a rotating magnetic field was studied using a fluxgate-based setup and was compared with the one recorded for hydrophobic and PEGylated particles. The particle phase lag rose after labeling with Herceptin, indicating the successful conjugation of Herceptin antibodies to the particles.
    • Sphingomonas starnbergensis sp. nov., isolated from a prealpine freshwater lake.

      Chen, Hong; Jogler, Mareike; Tindall, Brian J; Klenk, Hans-Peter; Rohde, Manfred; Busse, Hans-Jürgen; Overmann, Jörg; Bereich Mikrobiologie, Department Biologie I, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany. (2013-03)
      A novel type of freshwater bacterium was isolated from the prealpine mesotrophic Starnberger See (Bavaria, southern Germany). Cells of strain 382(T) were Gram-negative and rod-shaped, motile and creamy-white. The isolate was strictly aerobic, catalase- and oxidase-positive, and grew at pH values of 6-9 (optimum, pH 7) and temperatures of 10-37 °C (optimum, 28 °C). The genomic G+C content of strain 382(T) was 64.1 mol%. Based on 16S rRNA gene sequence analyses, strain 382(T) belongs to the family Sphingomonadaceae and clusters within the genus Sphingomonas. Sphingomonas histidinilytica UM 2(T) and Sphingomonas wittichii DSM 6014(T) were the closest relatives, as indicated by the highest 16S rRNA gene sequence similarities (97.1 % and 96.8 %, respectively). Sphingomonas paucimobilis DSM 1098(T) (the type species of the genus Sphingomonas) exhibited 95.3 % sequence similarity. This affiliation of strain 382(T) to the genus Sphingomonas is confirmed by the presence of Q-10 as the major respiratory quinone, two sphingoglycolipids, C14 : 0 2-OH as the major 2-hydroxy fatty acid and sym-homospermidine as the major polyamine. The main cellular fatty acids of strain 382(T) were C18 : 1ω7c (39 %), C16 : 1ω7c (21 %), C16 : 0 (10 %) and C14 : 0 2-OH (10 %). Based on the phylogenetic distance from other species of the genus Sphingomonas and its unusually high C16 : 1ω7c content, strain 382(T) represents a novel species of the genus Sphingomonas, for which the name Sphingomonas starnbergensis is proposed. The type strain is 382(T) ( = DSM 25077(T)  = LMG 26763(T)).
    • Genome sequence of the Antarctic rhodopsins-containing flavobacterium Gillisia limnaea type strain (R-8282T)

      Riedel, Thomas; Held, Brittany; Nolan, Matt; Lucas, Susan; Lapidus, Alla; Tice, Hope; Del Rio, Tijana Glavina; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; et al. (2013-02-07)
    • Cooperative plasminogen recruitment to the surface of Streptococcus canis via M protein and enolase enhances bacterial survival.

      Fulde, Marcus; Rohde, Manfred; Polok, Andy; Preissner, Klaus T; Chhatwal, Gursharan Singh; Bergmann, Simone; Helmholtz Centre for Infection Research (HZI), Department of Medical Microbiology, Braunschweig, Germany. marcus.fulde@web.de (2013)
      Streptococcus canis is a zoonotic pathogen capable of causing serious invasive diseases in domestic animals and humans. Surface-exposed M proteins and metabolic enzymes have been characterized as major virulence determinants in various streptococcal species. Recently, we have identified SCM, the M-like protein of S. canis, as the major receptor for miniplasminogen localized on the bacterial surface. The present study now characterizes the glycolytic enzyme enolase as an additional surface-exposed plasminogen-binding protein. According to its zoonotic properties, purified S. canis enolase binds to both human and canine plasminogen and facilitates degradation of aggregated fibrin matrices after activation with host-derived urokinase-type plasminogen activator (uPA). Unlike SCM, which binds to the C terminus of human plasminogen, the S. canis enolase interacts N terminally with the first four kringle domains of plasminogen, representing angiostatin. Radioactive binding analyses confirmed cooperative plasminogen recruitment to both surface-exposed enolase and SCM. Furthermore, despite the lack of surface protease activity via SpeB in S. canis, SCM is released and reassociated homophilically to surface-anchored SCM and heterophilically to surface-bound plasminogen. In addition to plasminogen-mediated antiphagocytic activity, reassociation of SCM to the bacterial surface significantly enhanced bacterial survival in phagocytosis analyses using human neutrophils.
    • Influence of internalin a murinisation on host resistance to orally acquired listeriosis in mice.

      Bergmann, Silke; Beard, Philippa M; Pasche, Bastian; Lienenklaus, Stefan; Weiss, Siegfried; Gahan, Cormac G M; Schughart, Klaus; Lengeling, Andreas; Infection and Immunity Division, The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush Veterinary Campus, Edinburgh EH25 9RG, UK. andreas.lengeling@roslin.ed.ac.uk. (2013)
      The bacterial surface protein internalin (InlA) is a major virulence factor of the food-born pathogen Listeria monocytogenes. It plays a critical role in the bacteria crossing the host intestinal barrier by a species-specific interaction with the cell adhesion molecule E-cadherin. In mice, the interaction of InlA with murine E-cadherin is impaired due to sequence-specific binding incompatibilities. We have previously used the approach of 'murinisation' to establish an oral listeriosis infection model in mice by exchanging two amino acid residues in InlA. This dramatically increases binding to mouse E-cadherin. In the present study, we have used bioluminescent murinised and non-murinised Listeria strains to examine the spatiotemporal dissemination of Listeria in four diverse mouse genetic backgrounds after oral inoculation.
    • Structure-informed design of an enzymatically inactive vaccine component for group A Streptococcus.

      Henningham, Anna; Ericsson, Daniel J; Langer, Karla; Casey, Lachlan W; Jovcevski, Blagojce; Chhatwal, G Singh; Aquilina, J Andrew; Batzloff, Michael R; Kobe, Bostjan; Walker, Mark J; et al. (2013)
      Streptococcus pyogenes (group A Streptococcus [GAS]) causes ~700 million human infections/year, resulting in >500,000 deaths. There is no commercial GAS vaccine available. The GAS surface protein arginine deiminase (ADI) protects mice against a lethal challenge. ADI is an enzyme that converts arginine to citrulline and ammonia. Administration of a GAS vaccine preparation containing wild-type ADI, a protein with inherent enzymatic activity, may present a safety risk. In an approach intended to maximize the vaccine safety of GAS ADI, X-ray crystallography and structural immunogenic epitope mapping were used to inform vaccine design. This study aimed to knock out ADI enzyme activity without disrupting the three-dimensional structure or the recognition of immunogenic epitopes. We determined the crystal structure of ADI at 2.5 Å resolution and used it to select a number of amino acid residues for mutagenesis to alanine (D166, E220, H275, D277, and C401). Each mutant protein displayed abrogated activity, and three of the mutant proteins (those with the D166A, H275A, and D277A mutations) possessed a secondary structure and oligomerization state equivalent to those of the wild type, produced high-titer antisera, and avoided disruption of B-cell epitopes of ADI. In addition, antisera raised against the D166A and D277A mutant proteins bound to the GAS cell surface. The inactivated D166A and D277A mutant ADIs are ideal for inclusion in a GAS vaccine preparation. There is no human ortholog of ADI, and we confirm that despite limited structural similarity in the active-site region to human peptidyl ADI 4 (PAD4), ADI does not functionally mimic PAD4 and antiserum raised against GAS ADI does not recognize human PAD4.
    • Adherence and invasion of streptococci to eukaryotic cells and their role in disease pathogenesis.

      Rohde, Manfred; Chhatwal, G Singh; Department of Medical Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany. manfred.rohde@helmholtz-hzi.de (2013)
      Streptococcal adhesion, invasion, intracellular trafficking, dissemination, and persistence in eukaryotic cells have a variety of implications in the infection pathogenesis. While cell adhesion establishes the initial host contact, adhering bacteria exploit the host cell for their own benefit. Internalization into the host cell is an essential step for bacterial survival and subsequent dissemination and persistence, thus playing a key role in the course of infection. This chapter summarizes the current knowledge about the diverse mechanisms of streptococcal adhesion to and invasion into different eukaryotic cells and the impact on dissemination and persistence which is reflected by consequences for the pathogenesis of streptococcal infections.
    • Host-pathogen interactions in streptococcal immune sequelae.

      Nitsche-Schmitz, D Patric; Chhatwal, Gursharan S; Helmholtz Centre for Infection Research, Inhoffenstraße 7, D-38124 Braunschweig, Germany. Patric.Nitsche@helmholtz-hzi.de (2013)
      Otherwise uncomplicated infections with Streptococcus pyogenes can cause two insidious immune sequelae known as post-streptococcal glomerulonephritis (PSGN) and acute rheumatic fever (ARF). These diseases follow with a latency of a few weeks or months after primary infection and are responsible for high mortality and morbidity. PSGN has also been linked to infections with group C streptococci of the species S. equi ssp. zooepidemicus (SESZ). Moreover, there are some indications that infection with group C and G streptococci (GCGS) of the subspecies Streptococcus dysgalactiae ssp. equisimilis (SDSE) leads to ARF. Despite decades of research, the picture of the molecular pathogenesis of streptococcal immune sequelae resembles a jigsaw puzzle. Herein we try to put some of the puzzle bits together that have been collected till date.
    • Complete genome sequence of the sulfate-reducing firmicute Desulfotomaculum ruminis type strain (DL(T)).

      Spring, Stefan; Visser, Michael; Lu, Megan; Copeland, Alex; Lapidus, Alla; Lucas, Susan; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A; et al. (2012-12-19)
      Desulfotomaculum ruminis Campbell and Postgate 1965 is a member of the large genus Desulfotomaculum which contains 30 species and is contained in the family Peptococcaceae. This species is of interest because it represents one of the few sulfate-reducing bacteria that have been isolated from the rumen. Here we describe the features of D. ruminis together with the complete genome sequence and annotation. The 3,969,014 bp long chromosome with a total of 3,901 protein-coding and 85 RNA genes is the second completed genome sequence of a type strain of the genus Desulfotomaculum to be published, and was sequenced as part of the DOE Joint Genome Institute Community Sequencing Program 2009.
    • Global Gene Transcriptome Analysis in Vaccinated Cattle Revealed a Dominant Role of IL-22 for Protection against Bovine Tuberculosis.

      Bhuju, Sabin; Aranday-Cortes, Elihu; Villarreal-Ramos, Bernardo; Xing, Zhou; Singh, Mahavir; Vordermeier, H Martin; Helmholtz Centre for Infection Research, Braunschweig, Germany ; Lionex Diagnostics Ltd, Braunschweig, Germany. (2012-12)
      Bovine tuberculosis (bTB) is a chronic disease of cattle caused by Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex group of bacteria. Vaccination of cattle might offer a long-term solution for controlling the disease and priority has been given to the development of a cattle vaccine against bTB. Identification of biomarkers in tuberculosis research remains elusive and the goal is to identify host correlates of protection. We hypothesized that by studying global gene expression we could identify in vitro predictors of protection that could help to facilitate vaccine development. Calves were vaccinated with BCG or with a heterologous BCG prime adenovirally vectored subunit boosting protocol. Protective efficacy was determined after M. bovis challenge. RNA was prepared from PPD-stimulated PBMC prepared from vaccinated-protected, vaccinated-unprotected and unvaccinated control cattle prior to M. bovis challenge and global gene expression determined by RNA-seq. 668 genes were differentially expressed in vaccinated-protected cattle compared with vaccinated-unprotected and unvaccinated control cattle. Cytokine-cytokine receptor interaction was the most significant pathway related to this dataset with IL-22 expression identified as the dominant surrogate of protection besides INF-γ. Finally, the expression of these candidate genes identified by RNA-seq was evaluated by RT-qPCR in an independent set of PBMC samples from BCG vaccinated and unvaccinated calves. This experiment confirmed the importance of IL-22 as predictor of vaccine efficacy.
    • Reclassification and emended description of Caulobacter leidyi as Sphingomonas leidyi comb. nov., and emendation of the genus Sphingomonas.

      Chen, Hong; Jogler, Mareike; Rohde, Manfred; Klenk, Hans-Peter; Busse, Hans-Jürgen; Tindall, Brian J; Spröer, Cathrin; Overmann, Jörg; Bereich Mikrobiologie, Department Biologie I, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany. (2012-12)
      'Caulobacter leidyi' DSM 4733(T) has been shown to be affiliated with the family Sphingomonadaceae instead of the Caulobacteraceae, and due to its poor characterization has been omitted from the current edition of Bergey's Manual of Systematic Bacteriology and removed to limbo. We isolated a novel sphingoglycolipid-containing dimorphic prosthecate bacterium, designated strain 247, from a pre-alpine freshwater lake. Strain 247 and 'Caulobacter leidyi' DSM 4733(T) were characterized in detail. The rod-shaped cells were Gram-stain-negative, aerobic, catalase- and oxidase-positive, and formed a stalk or polar flagellum. Both strains grew optimally at 28-30 °C, and pH 6.0-8.0. The major fatty acids were C(18 : 1)ω7c, C(16 : 0) and 11-methyl C(18 : 1)ω7c. C(14 : 0) 2-OH represents the major 2-hydroxy fatty acid. Q-10 was the major respiratory quinone and the major polar lipids were diphosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylcholine, three glycolipids, two phosphoaminolipids and two unidentified sphingoglycolipids. The major polyamine was sym-homospermidine. The G+C content of genomic DNA of strains 247 and DSM 4733(T) was 67.6 mol% and 67.0 mol%, respectively. According to 16S rRNA gene sequence analysis and DNA-DNA hybridization, strains DSM 4733(T) and 247 were phylogenetically closely related (99.6 % 16S rRNA gene sequence similarity, 82.9 % DNA-DNA hybridization value) and affiliated to the genus Sphingomonas. The closest recognized species was Sphingomonas aquatilis DSM 15581(T) (98.1 % sequence similarity). In addition, the presence of cystine arylamidase, absence of β-galactosidase, and the inability to utilize l-arabinose, galactose and sucrose distinguished strains DSM 4733(T) and 247 from most other members of the family Sphingomonadaceae. So far, the dimorphic life cycle that involves a prosthecate and a flagellated stage is unique for strains DSM 4733(T) and 247 among all members of the family Sphingomonadaceae. Therefore, Caulobacter leidyi is reclassified as Sphingomonas leidyi, with the type strain DSM 4733(T) ( = ATCC 15260(T) = CIP 106443(T) = VKM B-1368(T)) and strain 247 (DSM 25078 = LMG 26658) as an additional strain of this species.
    • Variability in the distribution of genes encoding virulence factors and putative extracellular proteins of Streptococcus pyogenes in India, a region with high streptococcal disease burden, and implication for development of a regional multisubunit vaccine.

      Sagar, Vivek; Bergmann, René; Nerlich, Andreas; McMillan, David J; Nitsche Schmitz, D Patric; Chhatwal, Gursharan S; Department of Medical Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany. (2012-11)
      Streptococcus pyogenes causes a wide variety of human diseases and is a significant cause of morbidity and mortality. Attempts to develop a vaccine were hampered by the genetic diversity of S. pyogenes across different regions of the world. This study sought to identify streptococcal antigens suitable for a region-specific vaccine in India. We used a two-step approach, first performing epidemiological analysis to identify the conserved antigens among Indian isolates. The second step consisted of validating the identified antigens by serological analysis. The 201 streptococcal clinical isolates from India used in this study represented 69 different emm types, with emm12 being the most prevalent. Virulence profiling of the North and South Indian S. pyogenes isolates with a custom-designed streptococcal virulence microarray identified seven conserved putative vaccine candidates. Collagen-like surface protein (SCI), putative secreted 5'-nucleotidase (PSNT), and C5a peptidase were found in 100% of the isolates, while R28, a putative surface antigen (PSA), and a hypothetical protein (HYP) were found in 90% of the isolates. A fibronectin binding protein, SfbI, was present in only 78% of the isolates. In order to validate the identified potential vaccine candidates, 185 serum samples obtained from patients with different clinical manifestations were tested for antibodies. Irrespective of clinical manifestations, serum samples showed high antibody titers to all proteins except for SCI and R28. Thus, the data indicate that PSNT, C5a peptidase, PSA, HYP, and SfbI are promising candidates for a region-specific streptococcal vaccine for the different parts of India.
    • Complete genome sequence of the moderately thermophilic mineral-sulfide-oxidizing firmicute Sulfobacillus acidophilus type strain (NALT)

      Anderson, Iain; Chertkov, Olga; Chen, Amy; Saunders, Elizabeth; Lapidus, Alla; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; et al. (2012-10-25)
    • Genome sequence of the orange-pigmented seawater bacterium Owenweeksia hongkongensis type strain (UST20020801(T)).

      Riedel, Thomas; Held, Brittany; Nolan, Matt; Lucas, Susan; Lapidus, Alla; Tice, Hope; Del Rio, Tijana Glavina; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; et al. (2012-10-10)
      Lau . 2005 is the sole member of the monospecific genus in the family a poorly characterized family at the genome level thus far. This family comprises seven genera within the class . Family members are known to be psychrotolerant, rod-shaped and orange pigmented (β-carotene), typical for . For growth, seawater and complex organic nutrients are necessary. The genome of UST20020801 is only the second genome of a member of the family whose sequence has been deciphered. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 4,000,057 bp long chromosome with its 3,518 protein-coding and 45 RNA genes is a part of the project.
    • Conserved anchorless surface proteins as group A streptococcal vaccine candidates.

      Henningham, Anna; Chiarot, Emiliano; Gillen, Christine M; Cole, Jason N; Rohde, Manfred; Fulde, Marcus; Ramachandran, Vidiya; Cork, Amanda J; Hartas, Jon; Magor, Graham; et al. (2012-10)
      Streptococcus pyogenes (group A Streptococcus (GAS)) causes ∼700 million human infections each year, resulting in over 500,000 deaths. The development of a commercial GAS vaccine is hampered by the occurrence of many unique GAS serotypes, antigenic variation within the same serotype, differences in serotype geographical distribution, and the production of antibodies cross-reactive with human tissue that may lead to autoimmune disease. Several independent studies have documented a number of GAS cell wall-associated or secreted metabolic enzymes that contain neither N-terminal leader sequences nor C-terminal cell wall anchors. Here, we applied a proteomic analysis of serotype M1T1 GAS cell wall extracts for the purpose of vaccine development. This approach catalogued several anchorless proteins and identified two protective vaccine candidates, arginine deiminase and trigger factor. These surface-exposed enzymes are expressed across multiple GAS serotypes exhibiting ≥99% amino acid sequence identity. Vaccine safety concerns are alleviated by the observation that these vaccine candidates lack human homologs, while sera from human populations suffering repeated GAS infections and high levels of autoimmune complications do not recognize these enzymes. Our study demonstrates anchorless cell surface antigens as promising vaccine candidates for the prevention of GAS disease.
    • first detection of trimethoprim resistance determinant dfrG in Streptococcus pyogenes clinical isolates in India.

      Bergmann, René; Sagar, Vivek; Nitsche-Schmitz, D Patric; Chhatwal, Gursharan S (2012-10)