The Infectious Microbe

177 Pages·2014·3.647 MB·English

by  William Firshein

The Infectious Microbe

The Infectious Microbe
William Firshein
1
1
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Library of Congress Cataloging-in-Publication Data
Firshein, William.
The infectious microbe / William Firshein.
p. cm.
Includes bibliographical references.
ISBN 978–0–19–932961–8 (alk. paper)
I. Title.
[DNLM: 1. Microbiological Phenomena. 2. Bioterrorism—prevention & control.
3. Communicable Diseases, Emerging. 4. Microbiology—history. 5. Virulence Factors. QW 4]
QR46
616.9’041—dc23
2013017114
9780199329618
9 8 7 6 5 4 3 2 1
Printed in the United States of America on acid-free paper
CONTENTS
Preface ix
Acknowledgments xiii
1. Introduction to the Infectious Microbe 1
A. The Scope of Microbial Life and Infectious Diseases 1
B. What Is a Pathogen? 4
C. The Relationship between a Pathogen and the Host It Infects Is Complex
and Varied 5
D. Susceptibility and Virulence Factors Are Closely Related 8
E. Major Groups of Pathogens Are Found throughout the Microbial
World 14
2. Fundamental Concepts of Biology and Chemistry Help Understand
Pathogenicity 21
A. Genetics: The Nature of the Gene and Its Chemical Structure
(DNA) 21
B. Metabolism Consists of Chemical Reactions, without Which Life Would
Not Exist 24
C. Biological Catalysts (Enzymes) Mediate Every Chemical Reaction
in the Cell 24
D. Genes Control the Synthesis and Expression of Enzymes (Which
Are Proteins) and Hence Control the Functioning of the Cell 25
E. The Mechanism of Protein Synthesis Involves a Complex Series
of Metabolic Reactions and Cellular Organelles, Starting with
DNA, a Related Macromolecule (RNA), and the Ribosome
(the Protein-Synthesizing Factory) 27
F. Gene Expression is Tightly Regulated to Economize and Preserve Cell
Integrity 33
G. Genetic Modifications in the Process of Gene Expression in Microbes
Are Varied and Complex. They Include Mutations, Transfer
Transformation (Recombination) of Genes from One Cell to Another,
and Many Other Variations of These Events 37
H. Modern Technologies 46
3. History of Microbiology 49
A. Voices in the Wilderness 49
B. The Golden Age and Modern Era 51
4. Emerging and Reemerging Diseases 56
A. Introduction 56
B. Definitions 58
C. Examples of Each 59
D. Role of Antibiotics 63
5. Case Histories 67
A. Introduction: Why Are the Following Examples Chosen? 67
B. HIV-AIDS: The Plague That Threatens Modern Society 67
1) Origins 68
2) Characteristics 69
3) Versatility 72
4) Structure of Genome 73
5) Treatment 73
6) Course of Infection 75
7) Conclusions 77
C. Tuberculosis: The White Plague, Ancient, But Still Lethal 77
1) Introduction 77
2) Description 78
3) Pathogenicity 79
4) Testing and Virulence Factors 82
5) Treatment 83
D. Streptococci and Staphylococci: More Intimacy Than We Desire 85
1) Introduction 85
2) General Descriptions 86
3) Staphylococci 87
4) Toxins 89
5) Staph Diseases 91
6) Treatment 93
7) Streptococci 93
8) Toxins 95
9) Other Streptococci 97
E. Ulcers and Helicobacter: The Uncommon Pathogen 98
1) Introduction 98
2) The Organism 99
3) The Disease 101
4) Pathogenicity 102
5) Toxins 102
6) Treatment 104
F. Cholera: A Pretty Nasty Beast 105
1) Introduction 105
2) The Organism 105
3) Pathogenicity 107
4) Diagnosis, Prevention, and Treatment of Cholera 109
5) The Agony of Haiti 110
6) Conclusions 110
G. Influenza: Bird Flu, Swine Flu, and All That Jazz 111
1) Introduction 111
2) The Virus and Pathogenicity 112
3) Spread, Prevention, and Treatment 115
4) Conclusion 116
6. Biofilms: City of Microbes and their Role in Pathogenicity 117
A. Introduction 117
B. Biofilms and Infectious Diseases 118
7. Biological Terrorism: Myths and Realities 122
A. Introduction 122
B. Historical Perspective 124
C. Bioterrorism Today: State of the Art and Preparedness 125
D. Conclusions 129
Glossary 131
Photo Credits 153
Index 155

PREFACE
Of the almost innumerable interactions between science and humanity, few
are as central as the life sciences, and in particular, the microbial world. This
world is immense and includes a tremendous variety of microscopic crea-
tures, such as bacteria, fungi, actinomycetes (organisms that lie midway be-
tween bacteria and fungi), viruses, and protozoa, among many other groups.
Because they are so intimately involved with life on this planet, they must be
taken into account in many ways when considering the public good. Such con-
cerns include their historical role in infectious diseases (e.g., bubonic plague
in the Middle Ages and the Spanish influenza pandemic after World War I),
as well as their roles in pollution; cycles of nature; climate change; bioterror-
ism; fermentation (e.g., production of alcohol from yeast and antibiotics by
other microorganisms); industrial microbiology; food spoilage (e.g., botulism
poisoning in incompletely sterilized canned foods); animal, plant, and crop
health; soil fertility; exploration of new oil deposits; genetic engineering (e.g.,
production of vital hormones such as insulin); space exploration; origin of
life; and yes, even normal development of healthy human beings and animals.
Just as a few vivid examples: 1) If microorganisms did not exist, every living
organism that ever died would still be here. They would not decay, and life
could not sustain itself. Only because of the incredible metabolic activities of
certain groups of microorganisms do the cells and tissues of dead organisms
“break down” chemically and return to their basic molecular forms to be used
by other living organisms for their own growth and development. 2) There
is no naturally occurring sterile environment that exists for living organisms
on this planet. All living beings are in intimate association with myriads of
microorganisms that change with time both in types and numbers. However,
artificial germ-free environments can be constructed for research and medical
purposes. One purpose involves analyzing what happens to animals born into
such an artificial environment. The result is ultimately fatal for them because
their immune (defense) capabilities (against infectious diseases) and digestive
systems do not develop normally. They require appropriate microorganisms to
activate both metabolic systems accurately (a result of evolution).
Even if one was not aware of all the activities of microorganisms de-
scribed above, and even if it was unclear why the activities of the vast majority
of microorganisms are beneficial and absolutely essential for our existence,
it is almost certain that their harmful capabilities in causing serious and
sometimes fatal diseases are well known and feared. From diseases caused ix