Download or read book Host Pathogen Interactions in Streptococcal Diseases written by G Singh Chhatwal and published by Springer Science & Business Media. This book was released on 2014-07-08 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streptococci are Gram-positive bacteria that cause a wide spectrum of diseases, such as pharyngitis, necrotizing fasciitis and streptococcal toxic shock syndrome, as well as rheumatic fever and rheumatic heart disease as sequelae. Antibiotics alone have not been able to control the disease and in spite of many efforts an effective vaccine is not yet available. A prerequisite for novel and successful strategies for combating these bacteria is a complete understanding of the highly complex pathogenic mechanisms involved, which are analyzed in this volume. In ten chapters, prominent authors cover various aspects including streptococcal diseases and global burden, epidemiology, adaptation and transmission, and molecular mechanisms of different diseases, as well as sequelae, vaccine development and clinical management. This book will serve as a valuable reference work for scientists, students, clinicians and public health workers and provide new approaches to meeting the challenge of streptococcal diseases.
Download or read book Streptococcus Pneumoniae written by Jeremy Brown and published by Academic Press. This book was released on 2015-05-08 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streptococcus Pneumoniae: Molecular Mechanisms of Host-Pathogen Interactions provides a comprehensive overview of our existing knowledge on Streptococcus pneumoniae antibiotic resistance, dissemination, and pathogenesis, including immunology. It presents a state-of-the-art overview of the implications of existing data, along with the areas of research that are important for future insights into the molecular mechanisms of pneumococcal infections and how to combat these infections. Users will find a timely update on the topic, as the dramatic increase in antibiotic resistance pneumoniae cases and limitations of the currently available pneumoniae vaccines are creating new concerns on these gram-positive bacteria that are endowed with a high virulence potential, and are the most common etiologic agent of respiratory and life-threatening invasive diseases. Provides an updated overview of our existing knowledge on Streptococcus pneumoniae antibiotic resistance, dissemination, and pathogenesis, including immunology Helps strengthen interdisciplinary networking and the focus of scientific resources by targeting epidemiology, vaccines, genetics, antibiotic resistance, clonal dissemination, Streptococcus pneumoniae biology, functional genomics, inflammasome, biomarkers, and more Multi-authored by leaders in the field who present a state-of-the-art overview of what the implications are of existing data, and the areas of research that are important for future insights into the molecular mechanisms of pneumococcal infections Supports combinatory networking in order to find new solutions in clinical therapies Reflects the most topical pneumococcal research trends
Download or read book Catabolite Sensing Regulatory Pathtways in Group A Streptocccus Control Virulence and Host pathogen Interactions written by Colin Christopher Kietzman and published by . This book was released on 2010 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a pathogen Streptococcus pyogenes (Group A streptococcus) is remarkable for its ability to cause a wide range of diseases and infect hundreds of millions of people yearly. Group A streptococcus faces a unique challenge in its pathogenesis cycle in that humans are its only known reservoir, and colonization and infection commonly occur in the same tissue. Thus to persist within a specific host niche Group A streptococcus has developed a sizable arsenal of effectors and control mechanisms allowing it to combat and adapt to the host immune response. In most cases alteration of regulatory pathways controlling transcription of virulence factor genes leads to significant changes in the ability of Group A streptococcus to cause disease. Several environmental signals and regulators effecting expression of virulence factors have been identified. One of the most pervasive signals effecting streptococcal virulence factor transcription is growth phase. In virtually all described incidences, virulence factor transcript abundance is influenced by growth phase, yet specific signals and mechanisms of sensing growth phase have remained elusive. These studies were undertaken to study the mechanisms of growth phase dependent transcriptional regulation of Group A streptococcal virulence factors, to ii elucidate global changes in transcriptional control due to altered growth phase regulators, and to examine the role of growth phase regulation in host- pathogen interactions during streptococcal infection. In pursuit of these goals, we initially analyzed a growth phase controlled physiologic trait, the production of H2O2, linked to virulence in related pathogens. We identified the gene responsible for H2O2 production, lactate oxidase (IctO), and through transcriptional and biochemical analyses identified the carbon catabolite control protein (CcpA) as a central transcriptional regulator of growth phase in response to glucose availability. Inactivation of CcpA revealed global changes in virulence factor transcription and overlap with another recently identified carbohydrate regulator, LacD1. Studies on these regulators indicated that while they respond to a common signal their effects on co- regulated genes are restricted to discrete times during streptococcal infection. Disruption of CcpA in particular led to attenuation of virulence and mis-regulation of a large contingent of virulence genes in infected tissues. Mis-regulation of target genes in the CcpA mutant correlated with an increase in host TNF[alpha] transcription, and occurred at times when wild type streptococci were causing maximal disease. Ablation of TNF[alpha] in the host led to an increase in local virulence in the CcpA deficient strain, and a switch from local to invasive disease during infection by wild type streptococci. In total, our studies have shown that growth phase regulation is comprised of multiple overlapping and organized pathways. Furthermore, functional growth phase regulation is necessary for Group A streptococcus to cause fully virulent disease, perhaps due to the interaction of growth phase regulated factors with host immune signaling pathways. Finally we have shown that TNF[alpha] is necessary to control localized infection and prevent dissemination to deeper tissues during infections by a streptococcal strain that normally causes localized non- spreading lesions. Understanding the mechanisms by which Group A streptococcus senses the host environment and interacts with the immune system is especially critical in studies of streptococcal pathogenesis and development of anti-streptococcal therapies. A broad spectrum streptococcal protective vaccine is unavailable and without treatment relatively minor streptococcal infections can progress to life threatening invasive disease or lead to highly disabling nonsuppurative sequelae. Our studies suggest that targeting growth phase sensitive regulatory pathways is a good strategy in combating streptococcal disease. In addition, in light of the use of many immunosuppressive therapies as treatments for various ailments, our results indicate the need for further investigations into the role TNF[alpha] in controlling human streptococcal diseases; patients receiving anti-TNF[alpha] treatments may be at an increased risk for serious infections by Group A streptococcus. Further analysis and identification of specific growth phase controlled factors contributing to attenuation of CcpA deficient strains, identification of factors involved in alteration of host-pathogen interactions resulting in disparate TNF[alpha] responses, and elucidation of the mechanisms by which TNF[alpha] production leads to control of localized infection will provide insights into Gram positive bacterial infection, and the molecular mechanisms determining the outcome of Group A streptococcal disease.
Download or read book Host pathogen Interactions in Severe Group A Streptococcal Infections written by Pontus Thulin and published by . This book was released on 2008 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Invasive Group A Streptococcal Infection written by Björn K. G. Eriksson and published by . This book was released on 1999 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Streptococci and the Host written by Thea Horaud and published by Springer Science & Business Media. This book was released on 2013-11-08 with total page 939 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streptococci and enterococci are the etiologic agents of infectious diseases that rank among the most severe in human pathology. The diagnosis, antibiotherapy, and prevention of the streptococcal diseases have improved considerably. However, the reemergence of severe streptococcal and enterococcal diseases constitutes a growing public health con cern, which remains open to scientific and medical debate. The XIII'h Lancefield International Symposium on Streptococci and Streptococcal Diseases, held at Institut Pasteur, Paris, France, September 16---2el, 1996, attracted 505 par ticipants from 43 countries. Twenty-two percent of the participants were students, a clear sign of the intense interest in this field. Of the 390 presentations made at the symposium, 260 were submitted as manuscripts for the Proceedings; we have included 249 of these in this volume. This symposium provided a forum for the presentation of the most recent findings and approaches to understanding several important fields, such as new aspects of infec tion, bacteria~host interactions, epidemiology, and molecular genetics of streptococci and enterococci. Over the last three years, the study of these subjects has expanded as increas ingly sophisticated methods of molecular analysis have been applied to investigate the bi ology of pathogenic streptococci and enterococci. Virulence, vaccine strategies, genetics, antibiotic resistance, epidemiology, and immunology are now being examined through the lens of molecular biology. The application of recently developed techniques to this field will continue to yield insight into the mechanism by which these organisms cause disease.
Download or read book Host pathogen Interaction During Streptococcus Pneumoniae Colonization and Infection written by Debby Bogaert and published by . This book was released on 2004 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bacterial Invasion of Host Cells written by Richard J. Lamont and published by Cambridge University Press. This book was released on 2004-03-29 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book concerns the intimate association between bacteria and host cells. Many bacterial pathogens are able to invade and survive within cells at mucosal membranes. Remarkably, the bacteria themselves orchestrate this process through the exploitation of host cellular signal transduction pathways. Intracellular invasion can lead to disruption of host tissue integrity and perturbation of the immune system. An understanding of the molecular basis of bacterial invasion and of host cell adaptation to intracellular bacteria will provide fundamental insights into the pathophysiology of bacteria and the cell biology of the host. The book details specific examples of bacteria that are masters of manipulation of eukaryotic cell signaling and relates these events to the broader context of host-pathogen interaction. Written by experts in the field, this book will be of interest to researchers and graduate students in microbiology, immunology, biochemistry, as well as molecular medicine and dentistry.
Download or read book Bacterial Pathogenesis written by Frank R. DeLeo and published by Humana Press. This book was released on 2010-12-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bacterial infections affect world health today as a leading cause of morbidity and mortality. This book presents in-depth methods and state-of-the-art protocols for investigating specific mechanisms of pathogenesis for a wide range of bacteria. Written by experts in the field, this invaluable collection includes protocols to study host-pathogen interactions, animal models of infection, and novel approaches to identifying therapeutic targets designed to control infections.
Download or read book Characterization of Host pathogen Interactions of Group B Streptococcus Within the Female Reproductive Tract written by and published by . This book was released on 2015 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Variation in Host pathogen Interactions Among Genetically Diverse Strains of Group B Streptococcus written by Michelle Lynn Korir and published by . This book was released on 2016 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Infectious Diseases Microbiology and Virology written by Luke S. P. Moore and published by Cambridge University Press. This book was released on 2019-12-05 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: A key resource for FRCPath and MRCP trainees, mapped to the current curriculum, using over 300 exam-style Q&A.
Download or read book Cell Surface and Cytosolic Proteins of Group B Streptococcus Adding New Dimensions in Its Colonization and Pathogenesis written by Manju Pai and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streptococcus agalactiae or Group B streptococcus (GBS) is an opportunistic human pathogen known for their invasive diseases caused in newborns, pregnant women, and nonpregnant adults. This pathogen even being an asymptomatic colonizer of adult humans, still they result in a broad range of disease manifestations starting from mild skin diseases to pneumonia, meningitis, and septicemia. Of the 10 GBS capsular types, the majority of invasive neonatal diseases are associated with the serotype III.¬†GBS is a pathogen that has developed some strategies to resist host immune defenses. The formidable array of GBS virulence factors makes this bacterium at the forefront of neonatal pathogens. The involvement of bacterial components in the host-pathogen interaction of GBS pathogenesis and its related diseases is thought to be due to a variety of virulence factors expressed by Streptococcus agalactiae. Pathogenic factors of streptococcus promote infections by their coordinated activity. These factors/determinants initially get a stimulus by the communication between specific ligands and their respective receptors in a host-pathogen interaction. These in turn activate adhesion and invasion mechanisms by mediating the attachment of pathogen via cell wall associated/secretory proteins, e.g., adhesins followed by their entry into the host cell eventually deciding their fate to live by activation of mechanisms like phagocytosis. These mediators/determinants also modulate the immune responses by the host toward the pathogen. A number of new GBS surface-exposed or secreted proteins have been identified (GBS immunogenic bacterial adhesion protein, leucine-rich repeat of GBS, serine-rich repeat proteins), the three-dimensional structures of known streptococcal proteins (Œ±C protein, C5a peptidase) have been solved, and an understanding of the pathogenetic role of ,Äúold,Äù and new determinants has been better defined in recent years. Recently, a 39kDa Invasion Inhibitory Factor (IIF) was isolated from GBS playing an important role in its invasion. A homogeneous non-toxic 39¬†kDa factor from the cytosol of GBS showing a homology with xenobiotic response element type transcriptional regulator protein adds another quill to the GBS protein panama, thus indicating that such protein molecules can be efficiently explored as suitable vaccine candidates. These observations add a novel aspect to bacterial pathogenesis where bacteria,Äôs own intracellular protein component can act as a potential therapeutic candidate by decreasing the severity of disease thus promoting its invasion inhibition.
Download or read book Bacterial Pathogenesis written by and published by Academic Press. This book was released on 1998-07-01 with total page 643 pages. Available in PDF, EPUB and Kindle. Book excerpt: Established almost 30 years ago, Methods in Microbiology is the most prestigious series devoted to techniques and methodology in the field. Now totally revamped, revitalized, with a new format and expanded scope, Methods in Microbiology will continue to provide you with tried and tested, cutting-edge protocols to directly benefit your research. Focuses on the methods most useful for the microbiologist interested in the way in which bacteria cause disease Includes section devoted to 'Approaches to characterising pathogenic mechanisms' by Stanley Falkow Covers safety aspects, detection, identification and speciation Includes techniques for the study of host interactions and reactions in animals and plants Describes biochemical and molecular genetic approaches Essential methods for gene expression and analysis Covers strategies and problems for disease control
Download or read book Addressing Emerging Infectious Disease Threats written by and published by . This book was released on 1994 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: This plan addresses the need to improve our ability to identify infectious disease threats and respond to them effectively by improving the public health infrastructure at the local, state and federal levels. The goals of the plan are surveillance (detect, promptly investigate, and monitor emerging pathogens, the diseases they cause, and the factors influencing their emergence); applied research (integrate laboratory science and epidemiology to optimize public health practice); prevention and control (enhance communication of public health information about emerging diseases and ensure prompt implementation of prevention strategies); and infrastructure (strengthen local, state, and federal public health infrastructures to support surveillance and implement prevention and control programs).
Download or read book Composition and Function written by Cole Ross McCutcheon and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Group B Streptococcus (GBS) is an opportunistic pathogen that asymptomatically colonizes the vaginal tract of approximately 30% of women. In individuals with an altered immune state such as the elderly, pregnant women, and neonates, GBS can cause invasive infections. During pregnancy, GBS frequently contributes to infections in utero that can result in chorioamnionitis, preterm birth, or miscarriage. The bacterial factors that promote these adverse outcomes, however, are under studied. For instance, previous reports have demonstrated that GBS produces membrane vesicles (MVs), which have been linked to adverse pregnancy outcomes in a murine model. Nonetheless, little is known about the composition of GBS MVs and their role in pathogenesis and impact on the immune response. Therefore, using genotypically diverse strains of GBS, I sought to examine MV production and composition, as well as their impact on ascending infection in vivo to better understand their role in GBS disease. While MVs contain a variety of immunomodulatory virulence factors, including hyaluronidase, C5a peptidase, and sialidase, the relative abundance of these virulence factors varies in a lineage dependent manner. With this information in hand, I then assessed the host response to GBS derived MVs using human THP-1 derived macrophages. I found that regardless of strain, MVs induce a potent proinflammatory immune response characterized by the production of proinflammatory cytokines and chemokines. Notably, many neutrophil chemokines were highly upregulated in response to MVs, which is consistent with observations seen during murine challenge with MVs. I went on to demonstrate that MVs, in the absence of t, induce a potent IL-1s response, which is dependent on caspase-1 and NLRP3, suggesting that the NLRP3 inflammasome is a sensor of GBS derived MVs. Previous data had suggested that MVs induce inflammation at the maternal-fetal interface. We have confirmed these findings and identified a potential mechanism for this inflammatory response. Furthermore, others utilized models of intra-amniotic injection that bypasses many immune defenses such as the extraplacental membranes and the cervix, which may prevent this response, while we assessed the role of MVs during vaginal challenge with GBS. However, we found that the addition of exogenous MVs does not promote ascending infection in vivo. While bacteria were able to ascend from the vaginal tract into gestational tissues, similar levels of bacteria were found regardless of the addition of exogenous MVs. Consistent with this observation, using flow cytometry we showed that neither exogenous MVs supplemented at the time of infection nor vaginal supplementation of MVs alone alter inflammatory responses at the maternal-fetal interface, suggesting that these innate barriers are capable of blocking MV mediated effects. The work presented here dramatically alters our understanding of the composition and host-pathogen interactions of GBS MVs, by substantially increasing our knowledge of both their composition and function during infection.
Download or read book Lipidomic Analysis of the Streptococcal Cellular Membrane written by Luke R. Joyce and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Streptococci are Gram-positive bacteria that natively colonize niches throughout the human body. While carriage of streptococci is mostly asymptomatic, they can be major human pathogens causing a variety of diseases across all age groups. Research on streptococcal mechanisms of pathogenicity, colonization, and transmission have identified virulence factors such as proteins, extracellular polysaccharides, intercellular communication pathways, and gene regulation pathways. These virulence factors have been demonstrated to aid in adherence to and invasion of human tissues and evasion of the immune system. A major component of the streptococcal cell is poorly understood: the cellular membrane. The cellular membrane is a critical site in host-pathogen interactions, providing an anchor for extracellular polysaccharides, protecting the internal workings of the bacterial cell, aiding transport of nutrients, and promoting survival in harsh conditions. The overarching goal of my dissertation work was to elucidate the biosynthetic pathway of phosphatidylcholine (PC) in Streptococcus mitis and S. oralis, members of the Mitis group streptococci, and to characterize the streptococcal cellular membrane using a culture medium that mimics the human host. In my research, I utilized lipidomics coupled with isotope tracing to discover that the glycerophosphocholine (GPC) pathway is required for PC biosynthesis in the Mitis group streptococcal species S. mitis, S. oralis, and S. pneumoniae. Briefly, the GPC pathway scavenges the major human metabolites GPC and lysophosphatidylcholine (lysoPC) and acylates them to form PC. Additionally, I determined that S. pneumoniae, S. pyogenes, and S. agalactiae synthesize PC when cultured in the presence of human serum. I demonstrate that lysoPC is the major substrate scavenged for an abbreviated GPC pathway in S. pyogenes and S. agalactiae. Furthermore, I characterized the structure of the novel aminoacylated glycolipid lysylglucosyl-diacylglcyerol (Lys-Glc-DAG) in S. agalactiae. I experimentally confirmed that the enzyme multiple peptide resistance factor (MprF) is the biosynthetic enzyme responsible for the lysine modification of Glc-DAG, establishing a novel glycolipid substrate for the S. agalactiae MprF. The MprF of S. agalactiae also catalyzes the addition of lysine to phosphatidylglycerol, forming lysyl-phosphatidylglycerol (Lys-PG), as expected based on prior knowledge of MprF in other bacteria. Using in vitro assays, I show that the lysine lipids, Lys-PG and Lys-Glc-DAG, impact the cellular membrane physiology such that S. agalactiae lacking the two lysine lipids are unable to survive in acidic conditions, have a more net negative outer surface charge, and exhibit significantly reduced human cell adherence and invasion. Taken together, my research provides critical insight into the cellular membrane of streptococci, evidence of cellular membrane remodeling through scavenging of major human metabolites, and the characterization of a novel aminoacylated glycolipid which impacts S. agalactiae colonization and invasion potential.
