The Experts below are selected from a list of 501 Experts worldwide ranked by ideXlab platform

Marcus Fulde - One of the best experts on this subject based on the ideXlab platform.

  • Novel Models of Streptococcus canis Colonization and Disease Reveal Modest Contributions of M-Like (SCM) Protein.
    Microorganisms, 2021
    Co-Authors: Ingrid Cornax, Marcus Fulde, Jacob Zulk, Joshua Olson, Victor Nizet, Kathryn A. Patras
    Abstract:

    Streptococcus canis is a common colonizing bacterium of the urogenital tract of cats and dogs that can also cause invasive disease in these animal populations and in humans. Although the virulence mechanisms of S. canis are not well-characterized, an M-like protein, SCM, has recently identified been as a potential virulence factor. SCM is a surface-associated protein that binds to host plasminogen and IgGs suggesting its possible importance in host-pathogen interactions. In this study, we developed in vitro and ex vivo blood component models and murine models of S. canis vaginal colonization, systemic infection, and dermal infection to compare the virulence potential of the zoonotic S. canis vaginal isolate G361 and its isogenic SCM-deficient mutant (G361∆scm). We found that while S. canis establishes vaginal colonization and causes invasive disease in vivo, the contribution of the SCM protein to virulence phenotypes in these models is modest. We conclude that SCM is dispensable for invasive disease in murine models and for resistance to human blood components ex vivo, but may contribute to mucosal persistence, highlighting a potential contribution to the recently appreciated genetic diversity of SCM across strains and hosts.

  • Draft Genome Sequence of Zoonotic Streptococcus canis Isolate G361.
    Genome announcements, 2017
    Co-Authors: Inga Eichhorn, Mark Van Der Linden, Michael Jarek, Marcus Fulde
    Abstract:

    ABSTRACT Here, we report the draft genome sequence of an SCM-positive Streptococcus canis strain, G361, isolated from a vaginal swab of a 40-year-old woman. The draft genome comprises 2,045,931 bp in 62 contigs.

  • SCM, the M Protein of Streptococcus canis Binds Immunoglobulin G.
    Frontiers in cellular and infection microbiology, 2017
    Co-Authors: Simone Bergmann, Inga Eichhorn, Manfred Rohde, Thomas P. Kohler, Sven Hammerschmidt, Oliver Goldmann, Marcus Fulde
    Abstract:

    The M protein of Streptococcus canis (SCM) is a virulence factor and serves as a surface-associated receptor with a particular affinity for mini-plasminogen, a cleavage product of the broad-spectrum serine protease plasmin. Here, we report that SCM has an additional high-affinity immunoglobulin G (IgG) binding activity. The ability of a particular S. canis isolate to bind to IgG significantly correlates with an scm-positive phenotype, suggesting a dominant role of SCM as an IgG receptor. Subsequent heterologous expression of SCM in non-IgG binding S. gordonii and Western Blot analysis with purified recombinant SCM proteins confirmed its IgG receptor function. As expected for a zoonotic agent, the SCM-IgG interaction is species-unspecific, with a particular affinity of SCM for IgGs derived from human, cats, dogs, horses, mice, and rabbits, but not from cows and goats. Similar to other streptococcal IgG-binding proteins, the interaction between SCM and IgG occurs via the conserved Fc domain and is, therefore, non-opsonic. Interestingly, the interaction between SCM and IgG-Fc on the bacterial surface specifically prevents opsonization by C1q, which might constitute another anti-phagocytic mechanism of SCM. Extensive binding analyses with a variety of different truncated SCM fragments defined a region of 52 amino acids located in the central part of the mature SCM protein which is important for IgG binding. This binding region is highly conserved among SCM proteins derived from different S. canis isolates but differs significantly from IgG-Fc receptors of S. pyogenes and S. dysgalactiae sub. equisimilis, respectively. In summary, we present an additional role of SCM in the pathogen-host interaction of S. canis. The detailed analysis of the SCM-IgG interaction should contribute to a better understanding of the complex roles of M proteins in streptococcal pathogenesis.

  • SCM-positive Streptococcus canis are predominant among pet-associated group G streptococci.
    Berliner und Munchener tierarztliche Wochenschrift, 2016
    Co-Authors: Gerdjosef Verkuhlen, Dennis Pagelow, Peter Valentinweigand, Marcus Fulde
    Abstract:

    Streptococcus (S.) canis is a neglected zoonotic pathogen with increasing impor- tance. Since knowledge about its distribution in pets in Germany is scant, we designed a study and tested 335 dogs and 71 cats for colonization by S. canis. S. canis was isolated from swabs taken from the perianal region by culture and subsequent identification was performed biochemically as well as by PCR. In total, 15.8% (53) of the canine and 8.5% (six) of the feline strains grown on Staphlyo- coccus/Streptococcus Selective Agar were tested positive for the Lancefield group G antigen. The vast majority of strains expressing the Lancefield Group G carbohy- drate (56 out of 59) were further identified as S. canis underlining their outstanding role among animal-associated Group G streptococci (GGS). Furthermore, 90.0% of the canine and 83.3% of the feline S. canis strains harbour the species-specific anti- phagocytic M protein homologue SCM, which has been described as an important virulence factor. In contrast, emm-genes typically encoded by human-specific GGS could not be detected in any of the S. canis isolates. Taken together, this study provides insights into the distribution of the neglected zoonotic pathogen S. canis in a population of pets in Germany. The presence of SCM in the vast majority of strains indicates their pathogenic potential.

  • Cooperative Plasminogen Recruitment to the Surface of Streptococcus canis via M Protein and Enolase Enhances Bacterial Survival
    mBio, 2013
    Co-Authors: Marcus Fulde, Manfred Rohde, Andy Polok, Klaus T. Preissner, Gursharan S. Chhatwal, Simone Bergmann
    Abstract:

    ABSTRACT 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. IMPORTANCE Streptococcal infections are a major issue in medical microbiology due to the increasing spread of antibiotic resistances and the limited availability of efficient vaccines. Surface-exposed glycolytic enzymes and M proteins have been characterized as major virulence factors mediating pathogen-host interaction. Since streptococcal infection mechanisms exert a subset of multicombinatorial processes, the investigation of synergistic activities mediated via different virulence factors has become a high priority. Our data clearly demonstrate that plasminogen recruitment to the Streptococcus canis surface via SCM and enolase in combination with SCM reassociation enhances bacterial survival by protecting against phagocytic killing. These data propose a new cooperative mechanism for prevention of phagocytic killing based on the synergistic activity of homophilic and heterophilic SCM binding in the presence of human plasminogen.

Simone Bergmann - One of the best experts on this subject based on the ideXlab platform.

  • Homophilic protein interactions facilitate bacterial aggregation and IgG-dependent complex formation by the Streptococcus canis M protein SCM.
    Virulence, 2019
    Co-Authors: Andreas G. Nerlich, Inga Eichhorn, Simone Bergmann, Thomas P. Kohler, Oliver Goldmann, Ingrid Cornax, Victor Nizet, Antje-maria Lapschies, Petra Krienke, Sven Hammerschmidt
    Abstract:

    Streptococcus canis is a zoonotic agent that causes serious invasive diseases in domestic animals and humans, but knowledge about its pathogenic potential and underlying virulence mechanisms is limited. Here, we report on the ability of certain S. canis isolates to form large bacterial aggregates when grown in liquid broth. Bacterial aggregation was attributed to the presence and the self-binding activity of SCM, the M protein of S. canis, as evaluated by bacterial sedimentation assays, immunofluorescence- and electron microscopic approaches. Using a variety of truncated recombinant SCM fragments, we demonstrated that homophilic SCM interactions occur via the N-terminal, but not the C-terminal part, of the mature M protein. Interestingly, when incubated in human plasma, SCM forms soluble protein complexes comprising its known ligands, immunoglobulin G (IgG) and plasminogen (Plg). Co-incubation studies with purified host proteins revealed that SCM-mediated complex formation is based on the interaction of SCM with itself and with IgG, but not with Plg or fibrinogen (Fbg), well-established constituents of M protein-mediated protein complexes in human-associated streptococci. Notably, these soluble, SCM-mediated plasma complexes harbored complement factor C1q, which can induce complement breakdown in the periphery and therefore represent another immune evasion mechanism of SCM.

  • SCM, the M Protein of Streptococcus canis Binds Immunoglobulin G.
    Frontiers in cellular and infection microbiology, 2017
    Co-Authors: Simone Bergmann, Inga Eichhorn, Manfred Rohde, Thomas P. Kohler, Sven Hammerschmidt, Oliver Goldmann, Marcus Fulde
    Abstract:

    The M protein of Streptococcus canis (SCM) is a virulence factor and serves as a surface-associated receptor with a particular affinity for mini-plasminogen, a cleavage product of the broad-spectrum serine protease plasmin. Here, we report that SCM has an additional high-affinity immunoglobulin G (IgG) binding activity. The ability of a particular S. canis isolate to bind to IgG significantly correlates with an scm-positive phenotype, suggesting a dominant role of SCM as an IgG receptor. Subsequent heterologous expression of SCM in non-IgG binding S. gordonii and Western Blot analysis with purified recombinant SCM proteins confirmed its IgG receptor function. As expected for a zoonotic agent, the SCM-IgG interaction is species-unspecific, with a particular affinity of SCM for IgGs derived from human, cats, dogs, horses, mice, and rabbits, but not from cows and goats. Similar to other streptococcal IgG-binding proteins, the interaction between SCM and IgG occurs via the conserved Fc domain and is, therefore, non-opsonic. Interestingly, the interaction between SCM and IgG-Fc on the bacterial surface specifically prevents opsonization by C1q, which might constitute another anti-phagocytic mechanism of SCM. Extensive binding analyses with a variety of different truncated SCM fragments defined a region of 52 amino acids located in the central part of the mature SCM protein which is important for IgG binding. This binding region is highly conserved among SCM proteins derived from different S. canis isolates but differs significantly from IgG-Fc receptors of S. pyogenes and S. dysgalactiae sub. equisimilis, respectively. In summary, we present an additional role of SCM in the pathogen-host interaction of S. canis. The detailed analysis of the SCM-IgG interaction should contribute to a better understanding of the complex roles of M proteins in streptococcal pathogenesis.

  • Cooperative Plasminogen Recruitment to the Surface of Streptococcus canis via M Protein and Enolase Enhances Bacterial Survival
    mBio, 2013
    Co-Authors: Marcus Fulde, Manfred Rohde, Andy Polok, Klaus T. Preissner, Gursharan S. Chhatwal, Simone Bergmann
    Abstract:

    ABSTRACT 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. IMPORTANCE Streptococcal infections are a major issue in medical microbiology due to the increasing spread of antibiotic resistances and the limited availability of efficient vaccines. Surface-exposed glycolytic enzymes and M proteins have been characterized as major virulence factors mediating pathogen-host interaction. Since streptococcal infection mechanisms exert a subset of multicombinatorial processes, the investigation of synergistic activities mediated via different virulence factors has become a high priority. Our data clearly demonstrate that plasminogen recruitment to the Streptococcus canis surface via SCM and enolase in combination with SCM reassociation enhances bacterial survival by protecting against phagocytic killing. These data propose a new cooperative mechanism for prevention of phagocytic killing based on the synergistic activity of homophilic and heterophilic SCM binding in the presence of human plasminogen.

  • Identification and characterization of the arginine deiminase system of Streptococcus canis.
    Veterinary microbiology, 2012
    Co-Authors: Angela Hitzmann, Gursharan S. Chhatwal, Manfred Rohde, Simone Bergmann, Marcus Fulde
    Abstract:

    Although Streptococcus (S.) canis is known to cause severe infections in dogs and cats and harbors a clear zoonotic potential, knowledge about physiology and pathogenesis is mostly elusive. The arginine deiminase system (ADS) has been described in certain streptococcal species and its role in the establishment of infection has been suggested. In this study we focused on the identification and characterization of the ADS in S. canis. Using genome sequencing and subsequent in silico analysis we identified the ADS of S. canis as a gene cluster composed of seven genes. RT-PCR analysis revealed that the ADS of S. canis is transcribed in four transcriptional units, comprising three monocistronical mRNAs and one operon structure. As a secondary metabolic pathway, the ADS of S. canis is strictly regulated by carbon catabolite repression (CCR) and arginine as demonstrated on transcriptional, translational, and enzymatical level, respectively. Furthermore, growth kinetics with a chemically defined medium clearly showed that arginine, the substrate of the ADS, is essential for the biological fitness of S. canis. Using Immuno-electron microscopy analysis, we observed a surface-exposed localization of the ADS enzymes arginine deiminase (ArcA), ornithine carbamoyltransferase (ArcB), and carbamate kinase (ArcC), respectively, which might suggest the contribution of the ADS to the development of streptococcal infections.

  • SCM, a novel M-like protein from Streptococcus canis binds (Mini)-plasminogen with high affinity and facilitates bacterial transmigration
    Biochemical Journal, 2011
    Co-Authors: Marcus Fulde, Manfred Rohde, Klaus T. Preissner, Gursharan S. Chhatwal, Andreas G. Nerlich, Angela Hitzmann, D.patric Nitsche-schmitz, Simone Bergmann
    Abstract:

    Streptococcus canis is an important zoonotic pathogen capable of causing serious invasive diseases in domestic animals and humans. In this study we report the binding of human plasminogen to S. canis and the recruitment of proteolytically active plasmin on its surface. The binding receptor for plasmin-ogen was identified as a novel M-like protein designated S. canis M-like protein (SCM). Surface plasmon resonance analyses, radio-active dot blot analyses and heterologous expression on the surface of S. gordonii confirmed the plasminogen-binding capa-bility of SCM. The binding domain was located within the N-terminus of SCM, which specifically bound to the C-terminal part of plasminogen (mini-plasminogen) comprising kringle domain 5 and the catalytic domain. In the presence of urokinase, SCM mediated plasminogen activation on the bacterial surface that was inhibited by serine protease inhibitors and lysine amino acid analogues. Surface-bound plasmin effectively degraded purified fibrinogen as well as fibrin clots, resulting in the dissolution of fibrin thrombi. Electron microscopic illustration and time lapse imaging demonstrated bacterial transmigration through fibrinous thrombi. This study led for the first time to the identification of SCM as novel receptor for (mini)-plasminogen mediating fibrinolytic activity of S. canis.

Mario Ramirez - One of the best experts on this subject based on the ideXlab platform.

  • Streptococcus canis Are a Single Population Infecting Multiple Animal Hosts Despite the Diversity of the Universally Present M-Like Protein SCM.
    Frontiers in microbiology, 2019
    Co-Authors: Marcos D. Pinho, Constança Pomba, Jose Melo-cristino, Geoffrey Foster, Miguel P. Machado, Johanna L. Baily, Thijs Kuiken, Mario Ramirez
    Abstract:

    Streptococcus canis is an animal pathogen which occasionally causes infections in humans. The S. canis M-like protein (SCM) encoded by the scm gene, is its best characterized virulence factor but previous studies suggested it could be absent in a substantial fraction of isolates. We studied the distribution and variability of the scm gene in 188 S. canis isolates recovered from companion animals (n = 152), wild animal species (n = 20), and humans (n =14). Multilocus sequence typing, including the first characterization of wildlife isolates, showed that the same lineages are present in all animal hosts, raising the possibility of extensive circulation between species. Whole-genome analysis revealed that emm-like genes found previously in S. canis correspond to divergent scm genes, indicating that what was previously believed to correspond to two genes is in fact the same scm locus. We designed primers allowing for the first time the successful amplification of the scm gene in all isolates. Analysis of the scm sequences identified 12 distinct types, which could be divided into two clusters: group I (76%, n = 142) and group II (24%, n = 46) sharing little sequence similarity. The predicted group I SCM showed extensive similarity with each other outside of the N-terminal hypervariable region and a conserved IgG binding domain. This domain was absent from group II SCM variants found in isolates previously thought to lack the scm gene, which also showed greater amino acid variability. Further studies are necessary to elucidate the possible host interacting partners of the group II SCM variants and their role in virulence.

  • Multilocus Sequence Analysis of Streptococcus canis Confirms the Zoonotic Origin of Human Infections and Reveals Genetic Exchange with Streptococcus dysgalactiae subsp. equisimilis
    Journal of clinical microbiology, 2013
    Co-Authors: Marcos D. Pinho, Sandra C. Matos, Constança Pomba, Antina Lubke-becker, Lothar H. Wieler, Silvia Preziuso, Jose Melo-cristino, Mario Ramirez
    Abstract:

    ABSTRACT Streptococcus canis is an animal pathogen that occasionally causes human infections. Isolates recovered from infections of animals (n = 78, recovered from 2000 to 2010 in three European countries, mainly from house pets) and humans (n = 7, recovered from 2006 to 2010 in Portugal) were identified by phenotypic and genotypic methods and characterized by antimicrobial susceptibility testing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and emm typing. S. canis isolates presented considerable variability in biochemical profiles and 16S rRNA. Resistance to antimicrobial agents was low, with the most significant being tet(M)- and tet(O)-mediated tetracycline resistance. MLST analysis revealed a polyclonal structure of the S. canis population causing infections, where the same genetic lineages were found infecting house pets and humans and were disseminated in distinct geographic locations. Phylogenetic analysis indicated that S. canis was a divergent taxon of the sister species Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis and found evidence of acquisition of genetic material by S. canis from S. dysgalactiae subsp. equisimilis. PFGE confirmed the MLST findings, further strengthening the similarity between animal and human isolates. The presence of emm-like genes was restricted to a few isolates and correlated with some MLST-based genetic lineages, but none of the human isolates could be emm typed. Our data show that S. canis isolates recovered from house pets and humans constitute a single population and demonstrate that isolates belonging to the main genetic lineages identified have the ability to infect the human host, providing strong evidence for the zoonotic nature of S. canis infection.

  • Genotypic Characterization of Streptococcus canis Isolated from Distinct Hosts with Special Emphasis on Multilocus Sequence Typing
    idweek.org, 2013
    Co-Authors: Marcos D. Pinho, Sandra C. Matos, Constança Pomba, Antina Lubke-becker, Lothar H. Wieler, Silvia Preziuso, Jose Melo-cristino, Mario Ramirez
    Abstract:

    Background: The animal pathogen Streptococcus canis is increasingly being noticed in human infections. Our aim was to develop a new multilocus sequence typing (MLST) scheme for Streptococcus canis and to compare isolates recovered from house pets and humans, in order to define the clonal structure of the S. canis population and explore the zoonotic potential of distinct S. canis genetic lineages. Methods: Eighty-five S. canis isolates recovered from infections in animals (n = 78, recovered from 2000 to 2010 in three European countries, mainly from house pets) and humans (n = 7, recovered from 2006 to 2010 in Portugal) were studied. Isolates were identified by API 20 Strep, 23S rRNA gene targeted PCR and 16S rRNA gene sequencing, and characterized by MLST, pulsed-field gel electrophoresis (PFGE) and emm typing. Results: All isolates were successfully typed with the proposed MLST scheme, indicating its applicability to S. canis from distinct sources. The MLST analysis showed a polyclonal structure of the S. canis population, where the same genetic lineages are found infecting house pets and humans and are disseminated in distinct geographic locations. PFGE confirmed the MLST findings, as it identified the same prevailing lineages and further strengthened the similarity between animal and human isolates. Phylogenetic analysis conducted with the 16S rRNA and MLST loci sequence data indicated that S. canis was a divergent taxon of the sister species Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis, and found evidence of acquisition of genetic material by S. canis from the latter species. The presence of emm-like genes was restricted to a few isolates and correlated with MLST defined genetic lineages. Conclusion: Our data shows that S. canis isolated from house pets and humans are a single population, and demonstrates that isolates belonging to the main genetic lineages identified are able to infect the human host, providing strong evidence for the zoonotic nature of S. canis infection in humans. A MLST database for S. canis was established at http://pubmlst.org/scanis/ (hosted by the Department of Zoology, University of Oxford, United Kingdom), constituting a valuable tool for future studies on the molecular epidemiology of this pathogen

  • Multilocus sequence analysis of Streptococcus canis confirms the zoonotic origin of human infections and reveals genetic exchange with Streptococcus dysgalactiae subsp. equisimilis.
    'American Society for Microbiology', 2013
    Co-Authors: Marcos D. Pinho, Sandra C. Matos, Constança Pomba, Antina Lubke-becker, Lothar H. Wieler, Silvia Preziuso, Jose Melo-cristino, Mario Ramirez
    Abstract:

    Streptococcus canis is an animal pathogen that occasionally causes human infections. Isolates recovered from infections of animals (n =78, recovered from 2000 to 2010 in three European countries, mainly from house pets) and humans (n = 7, recovered from 2006 to 2010 in Portugal) were identified by phenotypic and genotypic methods and characterized by antimicrobial susceptibility testing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE) and emm typing. S. canis isolates presented considerable variability in biochemical profiles and 16S rRNA. Resistance to antimicrobial agents was low, the most significant being tet(M)- and tet(O)-mediated tetracycline resistance. MLST analysis revealed a polyclonal structure of the S. canis population causing infections, where the same genetic lineages are found infecting house pets and humans and are disseminated in distinct geographic locations. Phylogenetic analysis indicated that S. canis was a divergent taxon of the sister species Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis and found evidence of acquisition of genetic material by S. canis from the latter species. PFGE confirmed the MLST findings further strengthening the similarity between animal and human isolates. The presence of emm-like genes was restricted to a few isolates and correlated with some MLST-based genetic lineages but none of the human isolates could be emm typed. Our data shows that S. canis isolated from house pets and humans constitute a single population and demonstrates that isolates belonging to the main genetic lineages identified have the ability to infect the human host, providing strong evidence for the zoonotic nature of S. canis infection

  • A new multilocus sequence typing scheme for the genotypic characterization of Streptococcus canis isolated from human and animal sources.
    2013
    Co-Authors: Marcos D. Pinho, Sandra C. Matos, Constança Pomba, Antina Lubke-becker, Lothar H. Wieler, Silvia Preziuso, Jose Melo-cristino, Mario Ramirez
    Abstract:

    Our aim was to develop a new multilocus sequence typing (MLST) scheme for Streptococcus canis. We also wanted to compare isolates recovered from different hosts, mainly house pets and humans, in order to define the clonal structure of the S. canis population and explore the zoonotic potential of distinct S. canis genetic lineages. Eighty-five S. canis isolates recovered from infections in animals (n = 78, recovered from 2000 to 2010 in three European countries, mainly from house pets) and humans (n = 7, recovered from 2006 to 2010 in Portugal) were studied. Isolates were identified by API 20 Strep, 23S rRNA gene targeted PCR and 16S rRNA gene sequencing, and characterized by MLST, pulsed-field gel electrophoresis (PFGE) and emm typing. All isolates were successfully typed with the proposed MLST scheme, indicating its applicability to S. canis from distinct sources. The MLST analysis showed a polyclonal structure of the S. canis population, where the same genetic lineages are found infecting house pets and humans and are disseminated in distinct geographic locations. PFGE confirmed the MLST findings, as it identified the same prevailing lineages and further strengthened the similarity between animal and human isolates. Phylogenetic analysis conducted with the 16S rRNA and MLST loci sequence data indicated that S. canis was a divergent taxon of the sister species Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis, and found evidence of acquisition of genetic material by S. canis from the latter species. The presence of emm-like genes was restricted to a few isolates and correlated with MLST defined genetic lineages. Our data shows that S. canis isolated from house pets and humans are a single population and demonstrates that isolates belonging to the main genetic lineages identified are able to infect the human host, providing strong evidence for the zoonotic nature of S. canis infection in humans. A MLST database for S. canis was established at http://pubmlst.org/scanis/ (hosted by the Department of Zoology, University of Oxford, United Kingdom), constituting a valuable tool for future studies on the molecular epidemiology of this pathogen

J F Prescott - One of the best experts on this subject based on the ideXlab platform.

  • Relatedness of Streptococcus canis from canine streptococcal toxic shock syndrome and necrotizing fasciitis.
    Canadian journal of veterinary research = Revue canadienne de recherche veterinaire, 1999
    Co-Authors: L M Dewinter, J F Prescott
    Abstract:

    The emergence of streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis (NF) in dogs caused by Streptococcus canis has been reported by our laboratory. Since clonal expansion is thought to be partially responsible for the spread of invasive strains of Streptococcus pyogenes in humans, the relatedness of 15 isolates of S. canis from canine STSS and/or NF was examined using pulsed field gel electrophoresis and biotyping; production of proteases and of a CAMP-like reaction were also examined. Only 2 of the 15 STSS and/or NF isolates were clonally related, suggesting that the emergence of canine STSS/NF is not the result of clonal expansion of one or more highly virulent strains of S. canis. All of the isolates produced proteases and demonstrated a CAMP-like reaction, which appear to be additional characteristics of S. canis.

  • Virulence of Streptococcus canis from canine streptococcal toxic shock syndrome and necrotizing fasciitis.
    Veterinary microbiology, 1999
    Co-Authors: L M Dewinter, D E Low, J F Prescott
    Abstract:

    The recent recognition of streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis (NF) in dogs caused by Streptococcus canis highlights our lack of knowledge regarding the mechanisms of virulence of this organism. Fifteen isolates of S. canis from cases of canine STSS and/or NF were examined for the presence of 10 Streptococcus pyogenes-associated virulence genes by Southern hybridizations using gene probes generated by PCR. The isolates lacked DNA with homology to eight of the 10 gene probes (speA, speB, speC, mf, ssa, scp, hasA, ska) under low stringency conditions. Thirteen and 15 of 15 isolates hybridized with streptolysin O and M protein gene probes, respectively. Twelve of 15 S. canis isolates were resistant to phagocytosis in canine blood. Electron microscopy revealed the presence of proteinaceous cell surface fibrillae. These results suggest that S. canis possesses M proteins and encodes streptolysin O, but lacks some of the other recognized virulence genes with significant homology to those in S. pyogenes.

Manfred Rohde - One of the best experts on this subject based on the ideXlab platform.

  • SCM, the M Protein of Streptococcus canis Binds Immunoglobulin G.
    Frontiers in cellular and infection microbiology, 2017
    Co-Authors: Simone Bergmann, Inga Eichhorn, Manfred Rohde, Thomas P. Kohler, Sven Hammerschmidt, Oliver Goldmann, Marcus Fulde
    Abstract:

    The M protein of Streptococcus canis (SCM) is a virulence factor and serves as a surface-associated receptor with a particular affinity for mini-plasminogen, a cleavage product of the broad-spectrum serine protease plasmin. Here, we report that SCM has an additional high-affinity immunoglobulin G (IgG) binding activity. The ability of a particular S. canis isolate to bind to IgG significantly correlates with an scm-positive phenotype, suggesting a dominant role of SCM as an IgG receptor. Subsequent heterologous expression of SCM in non-IgG binding S. gordonii and Western Blot analysis with purified recombinant SCM proteins confirmed its IgG receptor function. As expected for a zoonotic agent, the SCM-IgG interaction is species-unspecific, with a particular affinity of SCM for IgGs derived from human, cats, dogs, horses, mice, and rabbits, but not from cows and goats. Similar to other streptococcal IgG-binding proteins, the interaction between SCM and IgG occurs via the conserved Fc domain and is, therefore, non-opsonic. Interestingly, the interaction between SCM and IgG-Fc on the bacterial surface specifically prevents opsonization by C1q, which might constitute another anti-phagocytic mechanism of SCM. Extensive binding analyses with a variety of different truncated SCM fragments defined a region of 52 amino acids located in the central part of the mature SCM protein which is important for IgG binding. This binding region is highly conserved among SCM proteins derived from different S. canis isolates but differs significantly from IgG-Fc receptors of S. pyogenes and S. dysgalactiae sub. equisimilis, respectively. In summary, we present an additional role of SCM in the pathogen-host interaction of S. canis. The detailed analysis of the SCM-IgG interaction should contribute to a better understanding of the complex roles of M proteins in streptococcal pathogenesis.

  • Cooperative Plasminogen Recruitment to the Surface of Streptococcus canis via M Protein and Enolase Enhances Bacterial Survival
    mBio, 2013
    Co-Authors: Marcus Fulde, Manfred Rohde, Andy Polok, Klaus T. Preissner, Gursharan S. Chhatwal, Simone Bergmann
    Abstract:

    ABSTRACT 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. IMPORTANCE Streptococcal infections are a major issue in medical microbiology due to the increasing spread of antibiotic resistances and the limited availability of efficient vaccines. Surface-exposed glycolytic enzymes and M proteins have been characterized as major virulence factors mediating pathogen-host interaction. Since streptococcal infection mechanisms exert a subset of multicombinatorial processes, the investigation of synergistic activities mediated via different virulence factors has become a high priority. Our data clearly demonstrate that plasminogen recruitment to the Streptococcus canis surface via SCM and enolase in combination with SCM reassociation enhances bacterial survival by protecting against phagocytic killing. These data propose a new cooperative mechanism for prevention of phagocytic killing based on the synergistic activity of homophilic and heterophilic SCM binding in the presence of human plasminogen.

  • Identification and characterization of the arginine deiminase system of Streptococcus canis.
    Veterinary microbiology, 2012
    Co-Authors: Angela Hitzmann, Gursharan S. Chhatwal, Manfred Rohde, Simone Bergmann, Marcus Fulde
    Abstract:

    Although Streptococcus (S.) canis is known to cause severe infections in dogs and cats and harbors a clear zoonotic potential, knowledge about physiology and pathogenesis is mostly elusive. The arginine deiminase system (ADS) has been described in certain streptococcal species and its role in the establishment of infection has been suggested. In this study we focused on the identification and characterization of the ADS in S. canis. Using genome sequencing and subsequent in silico analysis we identified the ADS of S. canis as a gene cluster composed of seven genes. RT-PCR analysis revealed that the ADS of S. canis is transcribed in four transcriptional units, comprising three monocistronical mRNAs and one operon structure. As a secondary metabolic pathway, the ADS of S. canis is strictly regulated by carbon catabolite repression (CCR) and arginine as demonstrated on transcriptional, translational, and enzymatical level, respectively. Furthermore, growth kinetics with a chemically defined medium clearly showed that arginine, the substrate of the ADS, is essential for the biological fitness of S. canis. Using Immuno-electron microscopy analysis, we observed a surface-exposed localization of the ADS enzymes arginine deiminase (ArcA), ornithine carbamoyltransferase (ArcB), and carbamate kinase (ArcC), respectively, which might suggest the contribution of the ADS to the development of streptococcal infections.

  • SCM, a novel M-like protein from Streptococcus canis binds (Mini)-plasminogen with high affinity and facilitates bacterial transmigration
    Biochemical Journal, 2011
    Co-Authors: Marcus Fulde, Manfred Rohde, Klaus T. Preissner, Gursharan S. Chhatwal, Andreas G. Nerlich, Angela Hitzmann, D.patric Nitsche-schmitz, Simone Bergmann
    Abstract:

    Streptococcus canis is an important zoonotic pathogen capable of causing serious invasive diseases in domestic animals and humans. In this study we report the binding of human plasminogen to S. canis and the recruitment of proteolytically active plasmin on its surface. The binding receptor for plasmin-ogen was identified as a novel M-like protein designated S. canis M-like protein (SCM). Surface plasmon resonance analyses, radio-active dot blot analyses and heterologous expression on the surface of S. gordonii confirmed the plasminogen-binding capa-bility of SCM. The binding domain was located within the N-terminus of SCM, which specifically bound to the C-terminal part of plasminogen (mini-plasminogen) comprising kringle domain 5 and the catalytic domain. In the presence of urokinase, SCM mediated plasminogen activation on the bacterial surface that was inhibited by serine protease inhibitors and lysine amino acid analogues. Surface-bound plasmin effectively degraded purified fibrinogen as well as fibrin clots, resulting in the dissolution of fibrin thrombi. Electron microscopic illustration and time lapse imaging demonstrated bacterial transmigration through fibrinous thrombi. This study led for the first time to the identification of SCM as novel receptor for (mini)-plasminogen mediating fibrinolytic activity of S. canis.

  • SCM, a novel M-like protein from Streptococcus canis, binds (mini)-plasminogen with high affinity and facilitates bacterial transmigration
    The Biochemical journal, 2011
    Co-Authors: Marcus Fulde, Manfred Rohde, Klaus T. Preissner, Gursharan S. Chhatwal, Andreas G. Nerlich, Angela Hitzmann, D.patric Nitsche-schmitz, Simone Bergmann
    Abstract:

    Streptococcus canis is an important zoonotic pathogen capable of causing serious invasive diseases in domestic animals and humans. In the present paper we report the binding of human plasminogen to S. canis and the recruitment of proteolytically active plasmin on its surface. The binding receptor for plasminogen was identified as a novel M-like protein designated SCM (S. canis M-like protein). SPR (surface plasmon resonance) analyses, radioactive dot-blot analyses and heterologous expression on the surface of Streptococcus gordonii confirmed the plasminogen-binding capability of SCM. The binding domain was located within the N-terminus of SCM, which specifically bound to the C-terminal part of plasminogen (mini-plasminogen) comprising kringle domain 5 and the catalytic domain. In the presence of urokinase, SCM mediated plasminogen activation on the bacterial surface that was inhibited by serine protease inhibitors and lysine amino acid analogues. Surface-bound plasmin effectively degraded purified fibrinogen as well as fibrin clots, resulting in the dissolution of fibrin thrombi. Electron microscopic illustration and time-lapse imaging demonstrated bacterial transmigration through fibrinous thrombi. The present study has led, for the first time, to the identification of SCM as a novel receptor for (mini)-plasminogen mediating the fibrinolytic activity of S. canis.