The Staphylococci And Staphylococcal Pathogenesis

Members of the genus Staphylococcus play important roles in disease causation in humans and animals. Over the past decade, the completed sequencing of many staphylococcal genomes has contributed to a surge in the number of publications, which have promoted a tremendous advance in our knowledge of these important pathogens. Significant developments include the emergence of new and highly virulent strains of S. aureus, advances in tracking the evolution of human and animal adapted strains, a heightened appreciation of the role of mobile genetic elements in antibiotic resistance and pathogenesis, and important insights into staphylococcal physiology, immune evasion strategies, and cell surface proteins, as well as significant advances in vaccine development and therapeutics. This Research Topic will focus attention on the latest developments in these areas as they pertain to S. aureus and members of the coagulase-negative Staphylococci, and will also strive to identify areas of future development.

Staphylococcus aureus is resident in skin and nasal membranes with a formidable pathogenic potential to cause a variety of community and hospital acquired infections. This authoritative survey covers the impact of genome sequences into our understanding of MRSA and MSSA pathogenesis. World specialists from America, Germany, Japan, Sweden and the UK contribute knowledge and experience which will be welcome to researchers, practitioners and postgraduate students of immunology, microbiology, bacteriology and pharmacology worldwide. An authoritative survey that covers the impact of genome sequences into the understanding of MRSA and MSSA pathogenesis World specialists from America, Germany, Japan, Sweden and the UK contribute knowledge and experience

Staphylococcus aureus is now acknowledged as being the most important bacterial pathogen of humans. It usually produces localized disease but can be rapidly invasive, spreading through the tissues, invading bone, and seeding the bloodstream to produce a fulminant picture of septic shock, disseminated intravascular coagulation, and rapid death. Moreover, most strains of staph infections are becoming resistant to most antibiotics, thus posing a significant problem for hospitals and health care facilities. This book, a volume in the Infectious Agents and Pathogenesis series, presents chapters by the major researchers in the field.

Staphylococci remain the most important cause of hospital-acquiredinfections in the U.S. and MRSA has become the most common cause ofskin and soft tissue infection in many parts of the world. There is now a much greater understanding of the physiology andevolution of the staphylococci and this new edition reflects therapid advancements in knowledge about this pathogen and provides acomprehensive review from both clinical and basic scienceperspectives. The first section addresses the basic biology of thestaphylococci, their molecular genetics, host defenses and hostevasion, virulence determinants, mechanisms of antibioticresistance, and laboratory techniques. The second section dealswith epidemiology, and the third section provides an overview ofthe varied clinical manifestations of human staphylococcalinfections. The fourth section covers prevention and treatment ofthese often life-threatening infections. Written by experts from around the globe, this book is essentialreading for all clinicians and basic scientists studying thestaphylococci.

Staphylococcus was first recognized as a human pathogen in 1880 and was named for its grape cluster-like appearance. In 1884, Staphylococcus aureus was identified and named for its vibrant golden color, which was later found to be the result of golden toxin production. Here, experts examine in-depth patterns of S. aureus colonization and exposures in humans, mammals, and birds that have led to the development of various clinical diseases. The mode of transmission of S. aureus and different methods for its detection in different samples are defined. Conventional antibiotic options to treat this aggressive, multifaceted, and readily adaptable pathogen are becoming limited. Alternative, novel chemotherapeutics to target S. aureus are discussed in the pages within, including herbal medicines, bee products, and modes of delivery.

Although 30% of the healthy human population is colonized with various Staphylococcus species, some staphylococcal strains, referred to as opportunistic pathogens, can cause minor to life-threatening diseases. The pathogenicity of these bacteria depends on their virulence factors and the robustness of the regulatory networks expressing these virulence factors. Virulence factors of pathogenic Staphylococcus spp. consist of numerous toxins, enterotoxins (some of which act as superantigens), enzymes, and proteins (cytoplasmic, extracellular, and surface) that are regulated by two-component (TC) and quorum-sensing (QS) regulatory networks. To enter this niche, some other Staphylococcus species, such as Staphylococcus simulans, produce a potent endopeptidase called lysostaphin, which can inhibit the growth of pathogenic S. aureus. Some other Staphylococcus species produce autolysins and cationic peptides to win the intra- and inter-species competition. The outcome of this microbial invasion depends not only on pathogenic factors but also on the host's internal and external defense mechanisms, including a healthy skin microbiome. A healthy skin microbiome population can prevent colonization by other major pathogens. As normal host microflora, these commensals establish a complex relationship with the host as well as the surrounding microbial communities. This Special Issue of Microorganisms is focused on studies and recent advancements in our understanding of staphylococcal virulence mechanisms that enable Staphylococcus spp. either to successfully establish themselves as a colonizer or to overcome the host's defense system to cause infection along with our effort to make an anti-staphylococcal vaccine.

Members of the genus Staphylococcus and Streptococcus are the causative agnets of many human and animal diseases. Over the past decade the complete sequencing of many staphylococcal and streptococcal genomes has promoted a significant advance in our knowledge of these important pathogens. The pathogenicity of these bacteria is due to the expression of a large variety of virulence factors. Such determinants, which are cell wall-associated and secreted proteins, include adhesins that confer to the pathogen the ability to attach to extracellular matrix/plasma and host cell surfaces, proteins that contribute to host cell invasion and intracellular survival and soluble factors that decrease phagocytosis and modulate the immune response. Furthermore, these Gram-positive cocci in many natural environments (heart valve, lung, oral cavity, throat) and infections on implanted devices live in matrix-encased groups known as biofilms. Biofilms are specialized bacterial communities with high order organization analogous to that of a tissue in multicellular organism that adhere to abiotic or biological substrata and produce an exopolymeric matrix composed of polysaccarides, proteins, DNA or combination thereof. Bacteria within a biofilm persist in adverse conditions, show resistance to killing by antibiotics and to host immune defences and are difficult to eradicate and treat clinically. Therefore, understanding the mechanisms of biofilm development will allow us to effectively combat staphylococcal/streptococcal biofilm-based infections. This Research Topic will focus on the molecular components involved in biofilm formation by staphylococci and streptococci, the role they play in the development, maturation and dispersal of biofilm and on the regulatory aspects of such complex processes. The implication for the pathogenesis of infective diseases and potential therapeutic strategies against biofilm-based infections will be also discussed. The articles will highlight both the recent advances and future challenges inherent in this rapidly evolving area.