scholarly journals How to build a virulence factor: the role of three novel enzymes in the biosynthesis of the Group A Carbohydrate

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Azul Zorzoli ◽  
Benjamin Meyer ◽  
Benjamin Wagstaff ◽  
Helge Dorfmueller
Keyword(s):  
Streptococcus Pyogenes ◽  
Virulence Factor ◽  
Interdisciplinary Approach ◽  
Human Pathogens ◽  
Bacterial Surface ◽  
Streptococcal Species ◽  
Group A ◽  
Veterinary Importance ◽  
Surface Polysaccharide

The Group A carbohydrate (GAC), a bacterial surface polysaccharide, is an essential virulence factor of Streptococcus pyogenes required for growth and infection of humans.In terms of its chemical composition, this peptidoglycan-anchored polymer is mainly formed by a string of rhamnose sugars, with alternated modifications of N-acetylglucosamine and glycerolphosphate. The rhamnose polysaccharide (RhaPS) that forms the backbone chain is synthesised intracellularly by the sequential action of three rhamnosyltransferases named GacB, GacC and GacG. Importantly, deletion of any of these rhamnosyltransferases causes bacterialdeath. In this work, we used an interdisciplinary approach to demonstrate that: 1) GacB is a novel enzyme that initiates the RhaPS biosynthesis; 2) GacC catalyses the formation of a unique stem; 3) GacG elongates the RhaPS string by adding a yet unknown number of rhamnoses. Here, we also show that homologs from different streptococcal species can substitute GacB and GacC in the RhaPS production. In particular, we demonstrate that several human pathogens from the Streptococcus genus encompassed in the Lancefield serotyping scheme, and the dental pathogen Streptococcus mutans can replace S. pyogenes’ enzymes. In contrast, the homologs from S. pneumoniae sp. D39 did not, suggesting a different structural arrangement for its surface carbohydrate. Our results highlight the importance of the group carbohydrate biosynthesis pathways in the Streptococcus genus and open the door for the future development of multi-target compounds that could inhibit these enzymes in Streptococcus pyogenes and other pathogenic streptococci of clinical and veterinary importance.

Etiology, clinical presentation, laboratory diagnostics, pathogenesis of impetigo and treatment methods

2020 ◽  
pp. 64-70
Author(s):  
Anastasiya Laknitskaya
Keyword(s):  
Streptococcus Pyogenes ◽  
Skin Diseases ◽  
Group A Streptococcus ◽  
Antibiotic Sensitivity ◽  
Antioxidant Defense System ◽  
Laboratory Diagnostics ◽  
Treatment Methods ◽  
Group A ◽  
The Individual

Currently, one of the priority medical and social problems is the optimization of treatment methods for pyoderma associated with Streptococcus pyogenes — group A streptococcus (GAS). To date, the proportion of pyoderma, the etiological factor of which is Streptococcus pyogenes, is about 6 % of all skin diseases and is in the range from 17.9 to 43.9 % of all dermatoses. Role of the bacterial factor in the development of streptococcal pyoderma is obvious. Traditional treatment complex includes antibacterial drugs selected individually, taking into account the antibiotic sensitivity of pathognomonic bacteria, and it is not always effective. Currently implemented immunocorrection methods often do not take into account specific immunological features of the disease, the individual, and the fact that the skin performs the function of not only a mechanical barrier, but it is also an immunocompetent organ. Such an approach makes it necessary to conduct additional studies clarifying the role of factors of innate and adaptive immunity, intercellular mediators and antioxidant defense system, that allow to optimize the treatment of this pathology.

scholarly journals Interspecies Communication among Commensal and Pathogenic Streptococci

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Laura C. Cook ◽  
Breah LaSarre ◽  
Michael J. Federle
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Human Pathogens ◽  
Streptococcus Dysgalactiae ◽  
Interspecies Communication ◽  
Content Type ◽  
Streptococcal Species ◽  
Group A ◽  
Group B ◽  
Regulated Gene Expression

ABSTRACTQuorum sensing (QS) regulates diverse and coordinated behaviors in bacteria, including the production of virulence factors, biofilm formation, sporulation, and competence development. It is now established that some streptococci utilize Rgg-type proteins in concert with short hydrophobic peptides (SHPs) to mediate QS, and sequence analysis reveals that several streptococcal species contain highly homologous Rgg/SHP pairs. In group A streptococcus (GAS), two SHPs (SHP2 and SHP3 [SHP2/3]) were previously identified to be important in GAS biofilm formation. SHP2/3 are detected by two antagonistic regulators, Rgg2 and Rgg3, which control expression of theshpgenes. In group B streptococcus (GBS), RovS is a known virulence gene regulator and ortholog of Rgg2, whereas no apparent Rgg3 homolog exists. Adjacent torovSis a gene (shp1520) encoding a peptide nearly identical to SHP2. Using isogenic mutant strains and transcriptional reporters, we confirmed that RovS/SHP1520 comprise a QS circuit in GBS. More important, we performed experiments demonstrating that production and secretion of SHP1520 by GBS can modulate Rgg2/3-regulated gene expression in GAS intrans; likewise, SHP2/3 production by GAS can stimulate RovS-mediated gene regulation in GBS. An isolate ofStreptococcus dysgalactiaesubsp.equisimilisalso produced a secreted factor capable of simulating the QS circuits of both GAS and GBS, and sequencing confirms the presence of an orthologous Rgg2/SHP2 pair in this species as well. To our knowledge, this is the first documented case of bidirectional signaling between streptococcal species in coculture and suggests a role for orthologous Rgg/SHP systems in interspecies communication between important human pathogens.IMPORTANCEPathogenic streptococci, such as group A (GAS) and group B (GBS) streptococcus, are able to persist in the human body without causing disease but become pathogenic under certain conditions that are not fully characterized. Environmental cues and interspecies signaling between members of the human flora likely play an important role in the transition to a disease state. Since quorum-sensing (QS) peptides have been consistently shown to regulate virulence factor production in pathogenic species, the ability of bacteria to signal via these peptides may prove to be an important link between the carrier and pathogenic states. Here we provide evidence of a bidirectional QS system between GAS, GBS, andStreptococcus dysgalactiaesubsp.equisimilis, demonstrating the possibility of evolved communication systems between human pathogens.

Cysteine proteinase SpeB from Streptococcus pyogenes – a potent modifier of immunologically important host and bacterial proteins

2011 ◽  
Vol 392 (12) ◽  
pp. 1077-1088 ◽  
Author(s):  
Daniel C. Nelson ◽  
Julia Garbe ◽  
Mattias Collin
Keyword(s):  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Wide Spectrum ◽  
Cysteine Proteinase ◽  
Complement Components ◽  
Bacterial Surface ◽  
Bacterial Proteins ◽  
Disease States ◽  
Group A ◽  
Important Host

AbstractGroup A streptococcus (Streptococcus pyogenes) is an exclusively human pathogen that causes a wide spectrum of diseases ranging from pharyngitis, to impetigo, to toxic shock, to necrotizing fasciitis. The diversity of these disease states necessitates thatS. pyogenespossess the ability to modulate both the innate and adaptive immune responses. SpeB, a cysteine proteinase, is the predominant secreted protein fromS. pyogenes. Because of its relatively indiscriminant specificity, this enzyme has been shown to degrade the extracellular matrix, cytokines, chemokines, complement components, immunoglobulins, and serum protease inhibitors, to name but a few of the known substrates. Additionally, SpeB regulates other streptococcal proteins by degrading them or releasing them from the bacterial surface. Despite the wealth of literature on putative SpeB functions, there remains much controversy about this enzyme because many of reported activities would produce contradictory physiological results. Here we review all known host and bacterial protein substrates for SpeB, their cleavage sites, and discuss the role of this enzyme in streptococcal pathogenesis based on the current literature.

scholarly journals RscA, a Member of the MDR1 Family of Transporters, Is Repressed by CovR and Required for Growth of Streptococcus pyogenes under Heat Stress

2006 ◽  
Vol 188 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Tracy L. Dalton ◽  
Julie T. Collins ◽  
Timothy C. Barnett ◽  
June R. Scott
Keyword(s):  
Streptococcus Pyogenes ◽  
Abc Transporters ◽  
Group A Streptococcus ◽  
Response Regulator ◽  
Transcriptional Analysis ◽  
Sensor Kinase ◽  
Two Component System ◽  
Transcription Profiles ◽  
Group A

ABSTRACT The ability of Streptococcus pyogenes (group A streptococcus [GAS]) to respond to changes in environmental conditions is essential for this gram-positive organism to successfully cause disease in its human host. The two-component system CovRS controls expression of about 15% of the GAS genome either directly or indirectly. In most operons studied, CovR acts as a repressor. We previously linked CovRS to the GAS stress response by showing that the sensor kinase CovS is required to inactivate the response regulator CovR so that GAS can grow under conditions of heat, acid, and salt stress. Here, we sought to identify CovR-repressed genes that are required for growth under stress. To do this, global transcription profiles were analyzed by microarrays following exposure to increased temperature (40°C) and decreased pH (pH 6.0). The CovR regulon in an M type 6 strain of GAS was also examined by global transcriptional analysis. We identified a gene, rscA (regulated by stress and Cov), whose transcription was confirmed to be repressed by CovR and activated by heat and acid. RscA is a member of the MDR1 family of ABC transporters, and we found that it is required for growth of GAS at 40°C but not at pH 6.0. Thus, for GAS to grow at 40°C, CovR repression must be alleviated so that rscA can be transcribed to allow the production of this potential exporter. Possible explanations for the thermoprotective role of RscA in this pathogen are discussed.

scholarly journals Streptolysin O concentration and activity is central to in vivo phenotype and disease outcome in Group A Streptococcus infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jenny Clarke ◽  
Murielle Baltazar ◽  
Mansoor Alsahag ◽  
Stavros Panagiotou ◽  
Marion Pouget ◽  
...  
Keyword(s):  
Septic Arthritis ◽  
Rapid Development ◽  
Clinical Manifestations ◽  
Disease Outcome ◽  
Haemolytic Activity ◽  
Human Pathogens ◽  
Streptolysin O ◽  
Group A

AbstractGroup A Streptoccocus (GAS) is among the most diverse of all human pathogens, responsible for a range of clinical manifestations, from mild superficial infections such as pharyngitis to serious invasive infections such as necrotising fasciitis and sepsis. The drivers of these different disease phenotypes are not known. The GAS cholesterol-dependent cytolysin, Streptolysin O (SLO), has well established cell and tissue destructive activity. We investigated the role of SLO in determining disease outcome in vivo, by using two different clinical lineages; the recently emerged hypervirulent outbreak emm type 32.2 strains, which result in sepsis, and the emm type 1.0 strains which cause septic arthritis. Using clinically relevant in vivo mouse models of sepsis and a novel septic arthritis model, we found that the amount and activity of SLO was vital in determining the course of infection. The emm type 32.2 strain produced large quantities of highly haemolytic SLO that resulted in rapid development of sepsis. By contrast, the reduced concentration and lower haemolytic activity of emm type 1.0 SLO led to translocation of bacteria from blood to joints. Importantly, sepsis associated strains that were attenuated by deletion or inhibition of SLO, then also translocated to the joint, confirming the key role of SLO in determining infection niche. Our findings demonstrate that SLO is key to in vivo phenotype and disease outcome. Careful consideration should be given to novel therapy or vaccination strategies that target SLO. Whilst neutralising SLO activity may reduce severe invasive disease, it has the potential to promote chronic inflammatory conditions such as septic arthritis.

Plasminogen Is a Critical Host Pathogenicity Factor for Group A Streptococcal Infection.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 687-687
Author(s):  
Hongmin Sun ◽  
Ulrika Ringdahl ◽  
Jonathon W. Homeister ◽  
William P. Fay ◽  
N. Cary Engleberg ◽  
...  
Keyword(s):  
Blood Clot ◽  
Mammalian Species ◽  
Gas Injection ◽  
Coagulation Factor ◽  
Species Specificity ◽  
Regulatory Sequences ◽  
Bacterial Surface ◽  
Systemic Spread ◽  
Group A

Abstract Group A streptococci (GAS), a common human pathogen, secrete streptokinase (SK), which activates the host’s blood clot-dissolving protein, plasminogen (PLG). SK is highly specific for human PLG, exhibiting little or no activity against other mammalian species, including mouse. In addition to the species specificity of SK interaction with host PLG, species specificity has also been demonstrated for PLG receptors on the bacterial surface, such as the bacterial surface protein, PAM, and for interactions with fibrinogen. We generated a “humanized” transgenic mouse expressing human PLG under control of the mouse albumin gene regulatory sequences within a Bacteria Artificial Chromosome (BAC) transgene. The highest expressing transgenic founder line produced human PLG corresponding to ~17% of the PLG level in control human plasma (16.7±1.78) and largely rescued the prothromobtic morbidity otherwise observed in Plg null mice. Mice are generally highly resistant to subcutaneous infection by most human pathogenic GAS. However, introduction of human PLG expressed by the transgene markedly increased mortality to 75% from 20% in Tg− littermate control using the GAS strain 2616, exhibiting enhanced virulence due to site-directed mutation in the regulatory locus, csrRS. Similar differences in mortality were also observed with a wildtype GAS strain. The increased susceptibility of Tg+ mice to GAS was largely abrogated by deletion of the SK gene, demonstrating the major role of the PLG/SK interaction in GAS pathogenicity. Marked differences in mortality were also observed in Tg+ mice infected by the PAM expressing GAS strain AP53 and its PAM− isogenic variant, demonstrating a role for PAM in focusing PLG at the bacterial surface. We hypothesize that GAS hijack the host fibrinolytic system in order to circumvent local thrombosis and microvascular occlusion and reopen the vascular tree to systemic spread. Consistent with this model, the marked difference in mortality between Tg+ and Tg− mice was no longer observed when GAS were injected directly intravenously. In addition, a significant increase in bacterial colonies in the spleens of Tg+ mice was observed following subcutaneous GAS injection. Markedly increased mortality was also observed following GAS injection in C57BL/6J mice treated with the snake venom Ancrod, which proteolytically degrades plasma fibrinogen, consistent with a key role for fibrin deposition in host defense against GAS dissemination. In summary, activation of host plasminogen by SK leads to accelerated clearance of host fibrin and is a central mechanism for GAS invasion and spread. It is likely that similar interactions are central to the invasive program of other unrelated PA-associated pathogens that occupy diverse microenvironmental niches. The remarkable species specificity of SK for host PLG probably resulted from host and pathogen coevolution. These observations highlight the potential role of infectious disease as a critical force in the evolution of the hemostatic system and the unusual species specificity of many coagulation factor interactions.

scholarly journals Serine/Threonine Protein Kinase Stk Is Required for Virulence, Stress Response, and Penicillin Tolerance in Streptococcus pyogenes

2011 ◽  
Vol 79 (10) ◽  
pp. 4201-4209 ◽  
Author(s):  
Julia Bugrysheva ◽  
Barbara J. Froehlich ◽  
Jeffrey A. Freiberg ◽  
June R. Scott
Keyword(s):  
Streptococcus Pyogenes ◽  
Fatty Acid Biosynthesis ◽  
Group A Streptococcus ◽  
Acid Biosynthesis ◽  
Regulation Of Expression ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Genes Encoding ◽  
Group A

ABSTRACTGenes encoding one or more Ser/Thr protein kinases have been identified recently in many bacteria, including one (stk) in the human pathogenStreptococcus pyogenes(group A streptococcus [GAS]). We report that in GAS,stkis required to produce disease in a murine myositis model of infection. Using microarray and quantitative reverse transcription-PCR (qRT-PCR) studies, we found that Stk activates genes for virulence factors, osmoregulation, metabolism of α-glucans, and fatty acid biosynthesis, as well as genes affecting cell wall synthesis. Confirming these transcription studies, we determined that thestkdeletion mutant is more sensitive to osmotic stress and to penicillin than the wild type. We discuss several possible Stk phosphorylation targets that might explain Stk regulation of expression of specific operons and the possible role of Stk in resuscitation from quiescence.

scholarly journals A Highly Active and Negatively Charged Streptococcus pyogenes Lysin with a Rare d-Alanyl-l-Alanine Endopeptidase Activity Protects Mice against Streptococcal Bacteremia

2014 ◽  
Vol 58 (6) ◽  
pp. 3073-3084 ◽  
Author(s):  
Rolf Lood ◽  
Assaf Raz ◽  
Henrik Molina ◽  
Chad W. Euler ◽  
Vincent A. Fischetti
Keyword(s):  
Streptococcus Pyogenes ◽  
Mechanism Of Action ◽  
High Specificity ◽  
Content Type ◽  
Highly Active ◽  
Endopeptidase Activity ◽  
Streptococcal Species ◽  
Group A ◽  
Phage Lysin

ABSTRACTBacteriophage endolysins have shown great efficacy in killing Gram-positive bacteria. PlyC, a group C streptococcal phage lysin, represents the most efficient lysin characterized to date, with a remarkably high specificity against different streptococcal species, including the important pathogenStreptococcus pyogenes. However, PlyC is a unique lysin, in terms of both its high activity and structure (two distinct subunits). We sought to discover and characterize a phage lysin active againstS. pyogeneswith an endolysin architecture distinct from that of PlyC to determine if it relies on the same mechanism of action as PlyC. In this study, we identified and characterized an endolysin, termed PlyPy (phagelysin fromS.pyogenes), from a prophage infectingS. pyogenes. Byin silicoanalysis, PlyPy was found to have a molecular mass of 27.8 kDa and a pI of 4.16. It was active against a majority of group A streptococci and displayed high levels of activity as well as binding specificity against group B and C streptococci, while it was less efficient against other streptococcal species. PlyPy showed the highest activity at neutral pH in the presence of calcium and NaCl. Surprisingly, its activity was not affected by the presence of the group A-specific carbohydrate, while the activity of PlyC was partly inhibited. Additionally, PlyPy was activein vivoand could rescue mice from systemic bacteremia. Finally, we developed a novel method to determine the peptidoglycan bond cleaved by lysins and concluded that PlyPy exhibits a rared-alanyl-l-alanine endopeptidase activity. PlyPy thus represents the first lysin characterized fromStreptococcus pyogenesand has a mechanism of action distinct from that of PlyC.

scholarly journals T4 Pili Promote Colonization and Immune Evasion Phenotypes of Nonencapsulated M4 Streptococcus pyogenes

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Yi-Hsuan Chen ◽  
Shao-Hui Li ◽  
Yao-Cheng Yang ◽  
Shu-Hao Hsu ◽  
Victor Nizet ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Epithelial Cells ◽  
Streptococcus Pyogenes ◽  
Whole Blood ◽  
Human Pathogen ◽  
Human Whole Blood ◽  
Epidemiologic Surveillance ◽  
Group A ◽  
Hyaluronic Acid Capsule

ABSTRACT Streptococcus pyogenes (group A Streptococcus [GAS]) is an important human pathogen causing a broad spectrum of diseases and associated with significant global morbidity and mortality. Almost all GAS isolates express a surface hyaluronic acid capsule, a virulence determinant that facilitates host colonization and impedes phagocyte killing. However, recent epidemiologic surveillance has reported a sustained increase in both mucosal and invasive infections caused by nonencapsulated GAS, which questions the indispensable role of hyaluronic acid capsule in GAS pathogenesis. In this study, we found that pilus of M4 GAS not only significantly promotes biofilm formation, adherence, and cytotoxicity to human upper respiratory tract epithelial cells and keratinocytes, but also promotes survival in human whole blood and increased virulence in murine models of invasive infection. T4 antigen, the pilus backbone protein of M4 GAS, binds haptoglobin, an abundant human acute-phase protein upregulated upon infection and inflammation, on the bacterial surface. Haptoglobin sequestration reduces the susceptibility of nonencapsulated M4 GAS to antimicrobial peptides released from activated neutrophils and platelets. Our results reveal a previously unappreciated virulence-promoting role of M4 GAS pili, in part mediated by co-opting the biology of haptoglobin to mitigate host antimicrobial defenses. IMPORTANCE Group A Streptococcus (GAS) is a strict human pathogen causing more than 700 million infections globally each year. The majority of the disease-causing GAS are encapsulated, which greatly guarantees survival and dissemination in the host. Emergence of the capsule-negative GAS, such as M4 GAS, in recent epidemiologic surveillance alarms the necessity to elucidate the virulence determinants of these pathogens. Here, we found that M4 pili play an important role in promoting M4 GAS adherence and cytotoxicity to human pharyngeal epithelial cells and keratinocytes. The same molecule also significantly enhanced M4 GAS survival and replication in human whole blood and experimental murine infection. T4 antigen, which composes the backbone of M4 pili, was able to sequester the very abundant serum protein haptoglobin to further confer M4 GAS resistance to antibacterial substances released by neutrophils and platelets.

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