• Bifidobacterial enolase, a cell surface receptor for human plasminogen involved in the interaction with the host.

      Candela, Marco; Biagi, Elena; Centanni, Manuela; Turroni, Silvia; Vici, Manuela; Musiani, Francesco; Vitali, Beatrice; Bergmann, Simone; Hammerschmidt, Sven; Brigidi, Patrizia; et al. (2009-10)
      The interaction with the host plasminogen/plasmin system represents a novel component in the molecular cross-talk between bifidobacteria and human host. Here, we demonstrated that the plasminogen-binding bifidobacterial species B. longum, B. bifidum, B. breve and B. lactis share the key glycolytic enzyme enolase as a surface receptor for human plasminogen. Enolase was visualized on the cell surface of the model strain B. lactis BI07. The His-tagged recombinant protein showed a high affinity for human plasminogen, with an equilibrium dissociation constant in the nanomolar range. By site-directed mutagenesis we demonstrated that the interaction between the B. lactis BI07 enolase and human plasminogen involves an internal plasminogen-binding site homologous to that of pneumococcal enolase. According to our data, the positively charged residues Lys-251 and Lys-255, as well as the negatively charged Glu-252, of the B. lactis BI07 enolase are crucial for plasminogen binding. Acting as a human plasminogen receptor, the bifidobacterial surface enolase is suggested to play an important role in the interaction process with the host.
    • Contribution of Streptococcus anginosus to infections caused by groups C and G streptococci, southern India.

      Reissmann, Silvana; Friedrichs, Claudia; Rajkumari, Reena; Itzek, Andreas; Fulde, Marcus; Rodloff, Arne C; Brahmadathan, Kootallur N; Chhatwal, Gursharan S; Nitsche-Schmitz, D Patric; Helmholtz Centre for Infection Research, Braunschweig, Germany. (2010-04)
      Vellore, a region in southern India, has a high incidence of severe human infections with Beta-hemolytic group C and G streptococci (GCGS). To determine the causative species in these infections, we conducted 16S rRNA gene sequencing: Streptococcus dysgalactiae subsp. equisimilis (81%) and S. anginosus (19%) were the causative organisms in the 2-year study period (2006-2007). We used PCR to detect the virulence-related emm gene; results showed that it was restricted to S. dysgalactieae subsp. equisimilis isolates of 99.2% tested positive. Due to a novel marker, S. anginosus and S. constellatus can be quickly and accurately distinguished from other members of the genus. The notable contribution of the anginosus group to human infections suggests that this group of obligate pathogens deserves more attention in healthcare and research.
    • The genome sequence of Methanohalophilus mahii SLP(T) reveals differences in the energy metabolism among members of the Methanosarcinaceae inhabiting freshwater and saline environments.

      Spring, Stefan; Scheuner, Carmen; Lapidus, Alla; Lucas, Susan; Glavina Del Rio, Tijana; Tice, Hope; Copeland, Alex; Cheng, Jan-Fang; Chen, Feng; Nolan, Matt; et al. (2010)
      Methanohalophilus mahii is the type species of the genus Methanohalophilus, which currently comprises three distinct species with validly published names. Mhp. mahii represents moderately halophilic methanogenic archaea with a strictly methylotrophic metabolism. The type strain SLP(T) was isolated from hypersaline sediments collected from the southern arm of Great Salt Lake, Utah. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,012,424 bp genome is a single replicon with 2032 protein-coding and 63 RNA genes and part of the Genomic Encyclopedia of Bacteria and Archaea project. A comparison of the reconstructed energy metabolism in the halophilic species Mhp. mahii with other representatives of the Methanosarcinaceae reveals some interesting differences to freshwater species.
    • Kroppenstedtia eburnea gen. nov., sp. nov., a thermoactinomycete isolated by environmental screening, and emended description of the family Thermoactinomycetaceae Matsuo et al. 2006 emend. Yassin et al. 2009.

      von Jan, Mathias; Riegger, Nicole; Pötter, Gabriele; Schumann, Peter; Verbarg, Susanne; Spröer, Cathrin; Rohde, Manfred; Lauer, Bettina; Labeda, David P; Klenk, Hans-Peter (2011-09)
      A Gram-positive, spore-forming, aerobic, filamentous bacterium, strain JFMB-ATE(T), was isolated in 2008 during environmental screening of a plastic surface in grade C in a contract manufacturing organization in southern Germany. The isolate grew at temperatures of 25-50 °C and at pH 5.0-8.5, forming ivory-coloured colonies with sparse white aerial mycelia. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the family Thermoactinomycetaceae, except that the cell-wall peptidoglycan contained LL-diaminopimelic acid, while all previously described members of this family display this diagnostic diamino acid in meso-conformation. The DNA G+C content of the novel strain was 54.6 mol%, the main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, and the major menaquinone was MK-7. The major fatty acids had saturated C₁₄-C₁₆ branched chains. No diagnostic sugars were detected. Based on the chemotaxonomic results and 16S rRNA gene sequence analysis, the isolate is proposed to represent a novel genus and species, Kroppenstedtia eburnea gen. nov. sp. nov. The type strain is JFMB-ATE(T) ( = DSM 45196(T)  = NRRL B-24804(T)  = CCUG 59226(T)).
    • Rapid identification of viridans streptococci by mass spectrometric discrimination.

      Friedrichs, C; Rodloff, A C; Chhatwal, G S; Schellenberger, W; Eschrich, K; Institute for Medical Microbiology and Epidemiology of Infectious Diseases, University of Leipzig, Liebigstr. 24, D-04105 Leipzig, Germany. claudia.friedrichs@medizin.uni-leipzig.de (2007-08)
      Viridans streptococci (VS) are responsible for several systemic diseases, such as endocarditis, abscesses, and septicemia. Unfortunately, species identification by conventional methods seems to be more difficult than species identification of other groups of bacteria. The aim of the present study was to evaluate the use of cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) for the rapid identification of 10 different species of VS. A total of 99 VS clinical isolates, 10 reference strains, and 20 strains from our in-house culture collection were analyzed by MALDI-TOF-MS. To evaluate the mass-spectrometric discrimination results, all strains were identified in parallel by phenotypic and genotypic methods. MALDI-TOF-MS identified 71 isolates as the mitis group, 23 as the anginosus group, and 5 as Streptococcus salivarius. Comparison of the species identification results obtained by the MALDI-TOF-MS analyses and with the phenotypic/genotypic identification systems showed 100% consistency at the species level. Thus, MALDI-TOF-MS seems to be a rapid and reliable method for the identification of species of VS from clinical samples.
    • Sequencing and characterization of Pseudomonas aeruginosa phage JG004.

      Garbe, Julia; Bunk, Boyke; Rohde, Manfred; Schobert, Max; Helmholtz Centre for infection research, Inhoffenstr. 7, D-38124 Braunschweig, Germany. (2011)
      Phages could be an important alternative to antibiotics, especially for treatment of multiresistant bacteria as e.g. Pseudomonas aeruginosa. For an effective use of bacteriophages as antimicrobial agents, it is important to understand phage biology but also genes of the bacterial host essential for phage infection.
    • Virulence gene pool detected in bovine group C Streptococcus dysgalactiae subsp. dysgalactiae isolates by use of a group A S. pyogenes virulence microarray.

      Rato, Márcia G; Nerlich, Andreas; Bergmann, René; Bexiga, Ricardo; Nunes, Sandro F; Vilela, Cristina L; Santos-Sanches, Ilda; Chhatwal, Gursharan S; Centro de Recursos Microbiológicos, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. (2011-07)
      A custom-designed microarray containing 220 virulence genes of Streptococcus pyogenes (group A Streptococcus [GAS]) was used to test group C Streptococcus dysgalactiae subsp. dysgalactiae (GCS) field strains causing bovine mastitis and group C or group G Streptococcus dysgalactiae subsp. equisimilis (GCS/GGS) isolates from human infections, with the latter being used for comparative purposes, for the presence of virulence genes. All bovine and all human isolates carried a fraction of the 220 genes (23% and 39%, respectively). The virulence genes encoding streptolysin S, glyceraldehyde-3-phosphate dehydrogenase, the plasminogen-binding M-like protein PAM, and the collagen-like protein SclB were detected in the majority of both bovine and human isolates (94 to 100%). Virulence factors, usually carried by human beta-hemolytic streptococcal pathogens, such as streptokinase, laminin-binding protein, and the C5a peptidase precursor, were detected in all human isolates but not in bovine isolates. Additionally, GAS bacteriophage-associated virulence genes encoding superantigens, DNase, and/or streptodornase were detected in bovine isolates (72%) but not in the human isolates. Determinants located in non-bacteriophage-related mobile elements, such as the gene encoding R28, were detected in all bovine and human isolates. Several virulence genes, including genes of bacteriophage origin, were shown to be expressed by reverse transcriptase PCR (RT-PCR). Phylogenetic analysis of superantigen gene sequences revealed a high level (>98%) of identity among genes of bovine GCS, of the horse pathogen Streptococcus equi subsp. equi, and of the human pathogen GAS. Our findings indicate that alpha-hemolytic bovine GCS, an important mastitis pathogen and considered to be a nonhuman pathogen, carries important virulence factors responsible for virulence and pathogenesis in humans.