The Human Microbiota and Chronic Disease

Dysbiosis as a Cause of Human Pathology

Luigi Nibali, Brian Henderson, Luigi Nibali, Brian Henderson

• Publisher: Wiley-Blackwell
• Year: 2016
• Print ISBN:
  9781118982877
• Edition: 1
• eBook ISBN:
  9781118982891
• Topic: Biological Sciences
• Subtopic: Microbiology
• Index: Biological Sciences

Microbiota-associated pathology can be a direct result of changes in general bacterial composition, such as might be found in periodontitis and bacterial vaginosis, and/or as the result of colonization and/or overgrowth of so called keystone species. The disruption in the composition of the normal human microbiota, or dysbiosis, plays an integral role in human health and human disease.

The Human Microbiota and Human Chronic Disease: Dysbioses as a Cause of Human Pathology discusses the role of the microbiota in maintaining human health. The text introduces the reader to the biology of microbial dysbiosis and its potential role in both bacterial disease and in idiopathic chronic disease states.

Divided into five sections, the text delineates the concept of the human bacterial microbiota with particular attention being paid to the microbiotae of the gut, oral cavity and skin. A key methodology for exploring the microbiota, metagenomics, is also described. The book then shows the reader the cellular, molecular and genetic complexities of the bacterial microbiota, its myriad connections with the host and how these can maintain tissue homeostasis. Chapters then consider the role of dysbioses in human disease states, dealing with two of the commonest bacterial diseases of humanity – periodontitis and bacterial vaginosis. The composition of some, if not all microbiotas can be controlled by the diet and this is also dealt with in this section.  The discussion moves on to the major 'idiopathic' diseases afflicting humans, and the potential role that dysbiosis could play in their induction and chronicity. The book then concludes with the therapeutic potential of manipulating the microbiota, introducing the concepts of probiotics, prebiotics and the administration of healthy human faeces (faecal microbiota transplantation), and then hypothesizes as to the future of medical treatment viewed from a microbiota-centric position.

• Provides an introduction to dysbiosis, or a disruption in the composition of the normal human microbiota
• Explains how microbiota-associated pathology and other chronic diseases can result from changes in general bacterial composition
• Explores the relationship humans have with their microbiota, and its significance in human health and disease
• Covers host genetic variants and their role in the composition of human microbial biofilms, integral to the relationship between human health and human disease

Authored and edited by leaders in the field, The Human Microbiota and Human Chronic Disease will be an invaluable resource for clinicians, pathologists, immunologists, cell and molecular biologists, biochemists, and system biologists studying cellular and molecular bases of human diseases.

SECTION 1
An introduction to the human tissue microbiome

CHAPTER 1
The human microbiota: an historical perspective

Michael Wilson

UCL Eastman Dental Institute, University College London, United Kingdom

1.1 Introduction: the discovery of the human microbiota: why do we care?

The discovery by Antony van Leeuwenhoek in 1683 that we have a microbiota was very surprising and undoubtedly of great interest to 17th-century scientists. However, as modern-day researchers know only too well, this alone is not sufficient to ensure continued investigation of a subject. Further research into the microbes that inhabit humans proceeded at a very slow pace until it was realized that these microbes were able to cause disease and, much later, that they contribute to human health (i.e., in modern-day research parlance the research would be recognized as having “impact”). Our knowledge of those microbes with which we coexist has increased enormously during the last few years. An indication of the effort that has been devoted to determining the nature and function of the microbial communities inhabiting the various body sites of humans can be gleaned from the number of publications in this field listed in PubMed: in 2013 more than 2500 papers were published, nearly four times as many as in 2000.

What accounts for this recent huge growth of interest in the human microbiota? There appear to be two main driving forces: (a) increasing awareness of its importance in human disease, development, nutrition, behavior and wellbeing; (b) the development of technologies that enable us not only to identify which microbes are present but also to determine what these microbes are up to. In this chapter these two driving forces are described from a historical perspective.

1.2 The importance of the indigenous microbiota in health and disease

It has long been known that members of the indigenous microbiota of humans are responsible for a variety of infections, but only relatively recently has it been recognized that these microbes play an important role in maintaining human health and wellbeing.

1.2.1 The indigenous microbiota and human disease

In the late 19th and early 20th centuries many members of what we now recognize as the indigenous microbiota of humans were found to be the causative agents of a number of human infections (Table 1). However, at that time there was little understanding of what constituted the indigenous microbiota and therefore it was not realized that these newly recognized, disease-causing microbes were in fact regularly present on some, if not all, healthy humans and that, for the most part, they lived in harmony with their host (Table 1).

Table 1 Early discoveries of the involvement of members of the indigenous microbiota in human infections.

Year	Researcher	Organism	Disease	Reference
1881	Alexander Ogston	staphylococci	abscesses	1
1884	Friedrich Rosenbach	Strep. pyogenes	Wound infections	2
1884	Friedrich Rosenbach	Staphylococcus aureus	Wound infections	2
1884	Friedrich Rosenbach	Staphylococcus albus (i.e. Staph. epidermidis)	Wound infections	2
1884	Albert Fraenkel	Diplococcus pneumoniae (i.e. Strep. pneumoniae)	Lobar pneumonia	3
1890s	Theodor Escherich	Bacterium coli commune (i.e. Escherichia coli)	Colicystitis (i.e. urinary tract infection)	—
1892	George Nuttall and William Welch	Bacillus aerogenes capsulatus (i.e. Clostridium perfringens)	gangrene	4
1898	Veillon and Zuber	A variety of anaerobic species including Bacteroides fragilis, Fusobacterium nucleatum	gangrene	5
1906	Thomas Horder	Strep. salivarius	infective endocarditis	6
1891	Albert Fraenkel	Bacillus coli communis (i.e. Escherichia coli)	peritonitis	7

Subsequently, as knowledge of the indigenous microbiota improved, the involvement of members of these communities in disease processes became of great interest and was the subject of more intense research. Other members of the indigenous microbiota now known to cause human disease are shown in Table 2. More recently, it has become apparent not only that individual members of the microbiota are able to cause disease, but that shifts in the overall composition of the microbiota at a site can result in disease (Table 3). Such “dysbioses” are discussed in greater detail in subsequent chapters of this book. Recognition of the disease-inducing potential of the indigenous microbiota became an important stimulus to research into the characterization of the microbial communities associated with humans.

Table 2 Diseases caused by members of the indigenous microbiota (in addition to those listed in Table 1).

Organism	disease
Enterococcus faecalis	Urinary tract infections, endocarditis, meningitis, wound infections
Moraxella catarrhalis	Bronchopneumonia, sinusitis, otitis media
Haemophilus influenzae	Meningitis, pneumonia, sinusitis, otitis media, epiglottitis
Proteus mirabilis	Urinary tract infections
Helicobacter pylori	Gastritis, ulcers, carcinoma
Streptococcus mutans	Dental caries, endocarditis
Porphyromonas gingivalis	periodontitis
Actinomyces israelii	actinomycosis
Staphylococcus saprophyticus	Urinary tract infections
Neisseria meningitidis	meningitis
Malassezia spp.	Atopic dermatitis, seborrhoeic dermatitis, folliculitis
Gardnerella vaginalis	Bacterial vaginosis
Corynebacterium minutissimum	erythrasma

Table 3 Diseases resulting from dysbiosis.

...

Disease	Microbiota involved	Reference
obesity	intestinal tract	8

Table of contents

• Cover
• Title Page
• Table of Contents
• List of contributors
• Preface
• SECTION 1: An introduction to the human tissue microbiome
• SECTION 2: Microbiota-microbiota and microbiota-host interactions in health and disease
• SECTION 3: Dysbioses and bacterial diseases: Metchnikoff’s legacy
• SECTION 4: Dysbioses and chronic diseases: is there a connection?
• SECTION 5: Mirroring the future: dysbiosis therapy
• Index
• End User License Agreement