Molecular Pathogenesis Of Pneumococcus

Streptococcus pneumoniae has been for decades the number one bacterial killer of children in the world. Although vaccination with pneumococcal vaccines [PCV7, PCV10, and PCV13 (children) or PPSV23 (adults)] has helped decrease the burden of pneumococcal disease (PD), mortality remains high. Therefore, pathogenesis studies are still key toward our understanding of PD and its control. The introduction of pneumococcal vaccines has also created a niche for vaccine-escape clones. Moreover, the rise of multi-drug resistant clones around the world has also posed a serious threat in recent years. The proposed special issue of Frontiers in Cellular and Infection Microbiology highlights many of the recent advances that have been made in pneumococcal pathogenesis, colonization and antibiotic resistance by groups in Latino America, Europe, and the USA.

Streptococcus pneumoniae (the pneumococcus) is a commensal of the human nasopharynx during childhood, but also causes a variety of infections, such as otitis media (OM), pneumonia, bacteremia, and meningitis, mainly affecting infants, the elderly and immunocompromised patients. Pneumococcal pneumonia alone produces more child deaths, every year, than any other bacterial disease worldwide. To date, more than 90 distinct capsular serotypes have been identified. Current pneumococcal conjugate vaccines (PCV) protect against 7, 10 or 13 different pneumococcal types. These vaccines have decreased the burden of pneumococcal disease produced by vaccine types but provide poor protection against non-vaccine serotypes. Additionally, the increasing prevalence of multi-drug resistant S. pneumoniae strains results in more challenge for treatment of pneumococcal infections. Therefore, it is imperative to continue investigating the molecular pathogenesis of the pneumococcus. There are currently a variety of key virulence determinants known to be involved in pathogenesis of pneumococcal disease. Virulence factors and host immune defense are major players during pathogen - host interactions. Some metabolic pathways have also been shown to play a role in pneumococcal pathogenesis. These metabolic pathways include proteins involved in copper efflux, arginine metabolism, and zinc homeostasis. From the human host side, new host factors have been found to play essential roles in clearance of S. pneumoniae during infection, such as microRNA-155. Moreover, biofilm-like structures may alter both pneumococcal phenotypes and the host immunity during nasopharyngeal carriage and/or during disease. Understanding the interaction between pneumococcus and its human host is a key to combat pneumococcal infections. It has been well known for several years that pneumococcal pneumonia is worsened during poly-microbial infection. During the past few years, rapid progress has been made in this area. For example, it was recently shown that influenza A virus increases pneumococcal nasal colonization and it is a risk factor for pneumococcal pneumonia. Other important respiratory viruses and bacterial pathogens, such as Moraxella catarrhalis and Haemophilus influenzae, appear to increase the risk of pneumococcal colonization and disease. A better understanding of the molecular mechanism leading to these pathogenic synergisms will provide a fundamental basis for prevention and treatment of secondary pneumococcal infection. The elderly population is generally more susceptible to pneumococcal infections. In addition to their declined immunity, alteration of the microbiome seen in the elderly may play a role for the susceptibility of infection. Research with the elderly or using elderly animal infection models will largely enhance our knowledge and significantly reduce the morbidity and mortality caused by pneumococcal infections.

A state-of-the-art examination of research in this field and the impact of this gram-positive pathogen on human disease. * Provides coverage of topics in basic microbiology such as details of DNA transformation, molecular and medical epidemiology, the molecular basis of invasive disease, and various interactions with host defenses. * Presents important historical information on the field of pneumococcal research and suggests strategies for future investigation. * Serves as a valuable source of information for graduate and medical school students, infectious disease specialists, and field researchers in the pathogenesis of gram-positive bacteria.

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

Based on a workshop titled "Streptococcus pneumoniae: Molecular Biology and Mechanisms of Disease -- Update for the 1990s" held in September 1996 in Oeiras, Portugal, this volume contains some 40 contributions written by some 50 biochemists, molecular cmicrobiologists, geneticists, zoologists, pharmacologists, and pediatricians from 12 countries. Contributions are divided into six sections: an introductory segment addressing work to be done in the field and the disease's functional anatomy; the disease's chromosome structure, recombination, and cloning; capsule, cell wall, and virulence factors; Pneumococcal disease and animal models; antibiotic resistance; and surveillance and intervention.

This book provides up-to-date information on the crucial interaction of pathogenic bacteria and professional phagocytes, the host cells whose purpose is to ingest, kill, and digest bacteria in defense against infection. The introductory chapters focus on the receptors used by professional phagocytes to recognize and phagocytose bacteria, and the signal transduction events that are essential for phagocytosis of bacteria. Subsequent chapters discuss specific bacterial pathogens and the strategies they use in confronting professional phagocytes. Examples include Helicobacter pylori, Streptococcus pneumoniae, and Yersinae, each of which uses distinct mechanisms to avoid being phagocytosed and killed. Contrasting examples include Listeria monocytogenes and Mycobacterium tuberculosis, which survive and replicate intracellularly, and actually cooperate with phagocytes to promote their entry into these cells. Together, the contributions in this book provide an outstanding review of current knowledge regarding the mechanisms of phagocytosis and how specific pathogenic bacteria avoid or exploit these mechanisms.

Severe Community Acquired Pneumonia is a book in which chapters are authored and the same topics discussed by North American and European experts. This approach provides a unique opportunity to view the different perspectives and points of view on this subject. Severe CAP is a common clinical problem encountered in the ICU setting. This book reviews topics concerning the pathogenesis, diagnosis and management of SCAP. The discussions on the role of alcohol in severe CAP and adjunctive therapies are important topics that further our understanding of this severe respiratory infection.