Human Microbial Ecology

The aim of this comprehensively written volume is to provide a baseline of information on the normal microflora at various sites in the body. It focuses on the mouth, upper digestive tract, large intestine, skin, and urinogenital tract. Written in an easy-to-read format, this book highlights the level of detail available. For example, it explains that in the mouth and colon the data are extremely detailed and good quantitative information is available on large numbers of bacterial species. This work analyzes the similarities and differences between the microfloras of the various "internal" surfaces, and discusses the clear value of good taxonomy. It focuses on problems and extended research in the progress at other sites. Because this work researches the advances and discoveries made in specific areas of human microbial ecology, it is an ideal source for all who are involved in microbiology, bacteriology, and infectious diseases.

This advanced textbook provides a unique overview of the microbial communities (normal indigenous microbiota) inhabiting those regions of the human body that are exposed to the external environment, including the skin, eyes, oral cavity and the respiratory, urinary, reproductive and gastrointestinal tracts. In order to understand why particular organisms are able to colonise an anatomical region and why the resulting microbial community has a particular composition, an ecological approach is essential. Consequently, the key anatomical and physiological characteristics of each body site are described throughout the book. The crucial roles of the indigenous microbiota in protecting against exogenous pathogens, regulating the development of our immune system and mucosae, and providing nutrients are also discussed. The involvement of these organisms in infections of healthy and debilitated individuals are discussed throughout and methods of manipulating the composition of the indigenous microbiota for the benefit of human health are also described.

Dr. Joshua Lederberg - scientist, Nobel laureate, visionary thinker, and friend of the Forum on Microbial Threats - died on February 2, 2008. It was in his honor that the Institute of Medicine's Forum on Microbial Threats convened a public workshop on May 20-21, 2008, to examine Dr. Lederberg's scientific and policy contributions to the marketplace of ideas in the life sciences, medicine, and public policy. The resulting workshop summary, Microbial Evolution and Co-Adaptation, demonstrates the extent to which conceptual and technological developments have, within a few short years, advanced our collective understanding of the microbiome, microbial genetics, microbial communities, and microbe-host-environment interactions.

Groundbreaking research over the last 10 years has given rise to the hologenome concept of evolution. This concept posits that the holobiont (host plus all of its associated microorganisms) and its hologenome (sum of the genetic information of the host and its symbiotic microorganisms), acting in concert, function as a unique biological entity and therefore as a level of selection in evolution. All animals and plants harbor abundant and diverse microbiota, including viruses. Often the amount of symbiotic microorganisms and their combined genetic information far exceed that of their host. The microbiota with its microbiome, together with the host genome, can be transmitted from one generation to the next and thus propagate the unique properties of the holobiont. The microbial symbionts and the host interact in a cooperative way that affects the health of the holobiont within its environment. Beneficial microbiota protects against pathogens, provides essential nutrients, catabolizes complex polysaccharides, renders harmful chemicals inert, and contributes to the performance of the immune system. In humans and animals, the microbiota also plays a role in behavior. The sum of these cooperative interactions characterizes the holobiont as a unique biological entity. Genetic variation in the hologenome can be brought about by changes in either the host genome or the microbial population genomes (microbiome). Evolution by cooperation can occur by amplifying existing microbes, gaining novel microbiota and by acquiring microbial and viral genes. Under environmental stress, the microbiome can change more rapidly and in response to more processes than the host organism alone and thus influences the evolution of the holobiont. Prebiotics, probiotics, synbiotics and phage therapy are discussed as applied aspects of the hologenome concept.

People's desire to understand the environments in which they live is a natural one. People spend most of their time in spaces and structures designed, built, and managed by humans, and it is estimated that people in developed countries now spend 90 percent of their lives indoors. As people move from homes to workplaces, traveling in cars and on transit systems, microorganisms are continually with and around them. The human-associated microbes that are shed, along with the human behaviors that affect their transport and removal, make significant contributions to the diversity of the indoor microbiome. The characteristics of "healthy" indoor environments cannot yet be defined, nor do microbial, clinical, and building researchers yet understand how to modify features of indoor environmentsâ€"such as building ventilation systems and the chemistry of building materialsâ€"in ways that would have predictable impacts on microbial communities to promote health and prevent disease. The factors that affect the environments within buildings, the ways in which building characteristics influence the composition and function of indoor microbial communities, and the ways in which these microbial communities relate to human health and well-being are extraordinarily complex and can be explored only as a dynamic, interconnected ecosystem by engaging the fields of microbial biology and ecology, chemistry, building science, and human physiology. This report reviews what is known about the intersection of these disciplines, and how new tools may facilitate advances in understanding the ecosystem of built environments, indoor microbiomes, and effects on human health and well-being. It offers a research agenda to generate the information needed so that stakeholders with an interest in understanding the impacts of built environments will be able to make more informed decisions.

Individually and collectively, resident microbes play important roles in host health and survival. Shaping and shaped by their host environments, these microorganisms form intricate communities that are in a state of dynamic equilibrium. This ecologic and dynamic view of host-microbe interactions is rapidly redefining our view of health and disease. It is now accepted that the vast majority of microbes are, for the most part, not intrinsically harmful, but rather become established as persistent, co-adapted colonists in equilibrium with their environment, providing useful goods and services to their hosts while deriving benefits from these host associations. Disruption of such alliances may have consequences for host health, and investigations in a wide variety of organisms have begun to illuminate the complex and dynamic network of interaction - across the spectrum of hosts, microbes, and environmental niches - that influence the formation, function, and stability of host-associated microbial communities. Microbial Ecology in States of Health and Disease is the summary of a workshop convened by the Institute of Medicine's Forum on Microbial Threats in March 2013 to explore the scientific and therapeutic implications of microbial ecology in states of health and disease. Participants explored host-microbe interactions in humans, animals, and plants; emerging insights into how microbes may influence the development and maintenance of states of health and disease; the effects of environmental change(s) on the formation, function, and stability of microbial communities; and research challenges and opportunities for this emerging field of inquiry.

The Human Microbiota offers a comprehensive review of all human-associated microbial niches in a single volume, focusing on what modern tools in molecular microbiology are revealing about human microbiota, and how specific microbial communities can be associated with either beneficial effects or diseases. An excellent resource for microbiologists, physicians, infectious disease specialists, and others in the field, the book describes the latest research findings and evaluates the most innovative research approaches and technologies. Perspectives from pioneers in human microbial ecology are provided throughout.

This book highlights the hidden world of microbiomes, viromes, and biofilms on and inside humans. Our bodies have microbiomes, which contain various bacterial communities, and viromes, which contain viruses. These invisible residents are vital to health and sickness. Infections often result from microbiome imbalances. Pathogenic bacteria can outcompete beneficial ones, causing gut dysbiosis and disease. Understanding this interaction allows probiotics to restore balance and fight infections. Microbes have a major impact on the gut-brain axis. Gut bacteria affect mood, behavior, and neurodegenerative illnesses by producing neurotransmitters and influencing brain development. The "diabesity" relationship to microbiome changes underscores its relevance in metabolic illnesses like diabetes and NAFLD. The microbiota can also affect cancer progression. Specific bacterial strains may promote tumor growth or prevent metastasis, enabling microbiome-based cancer treatments. Probiotics—live bacteria—have enormous potential. Beneficial strains can improve intestinal balance, fight infections, and treat diabetes and autoimmune conditions. Fecal transplants or co-sleeping may modify microbial ecosystems and health effects. Microbiomes, viromes, and biofilms are complex, requiring advanced tools. The makeup, function, and interactions of these communities can be characterized using next-generation sequencing (NGS). As NGS technology advances, researchers explore this hidden world, offering a future where microbiome manipulation underpins customized therapy and preventive healthcare. This area has great potential for understanding health, improving well-being, and fighting diseases in innovative ways.