Download Microbiology Chapter 1

Microbial World and You
Chapter 1
What is Microbiology?
Micro - too small to be seen with the naked
eye
w Bio - life
w ology - study of
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Organisms included in the study
of Microbiology
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1. Bacteria
2. Protozoans
3. Algae
4. Parasites
5. Yeasts and Molds
• Fungi
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6. Viruses
Bacteriology
w Protozoology
w Phycology
w Parasitology
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Mycology
w Virology
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Microorganisms - Microbes - Germs
5 Kingdoms of Living Organisms
1. Animalia
w 2. Plantae
w 3. Fungi
w 4. Protista
w 5. Monera - Bacteria and Cyanobacteria
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Eukaryotic vs. Prokaryotic
5 Characteristics of Life
1. Cells
w 2. Maintain structure by taking up
chemicals and energy from the environment
w 3. Respond to stimuli in the external
environment
w 4. Reproduce and pass on their organization
to their offspring
w 5. Evolve and adapt to the environment
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Taxonomic Classification
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Kingdom
Phylum
Class
Order
Family
Genus
species
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Man
Animalia
Chordata
Mammalia
Primate
Hominidae
Homo
sapien
Taxonomic Classification
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Kingdom
Phylum
Class
Order
Family
Genus
species
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Cat
Animalia
Chordate
Mammalia
Carnivora
Felidae
Felis
domestica
Binomial System of Taxonomic
Classification
Use only the Genus and species
w Homo sapien
w Felis domestica
w Escherichia coli
w Genus and species are either underlined or
italicized
w Genus is always capitilized
w species is never capitilized
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Classification System
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3 Domains
1978 Carl Woese
• 1. Bacteria
• Unicellular prokaryotes with cell wall containing
peptidoglycan
• 2. Archaea
• Unicellular prokaryotes with no peptodoglycan in
cell wall
• 3. Eukarya
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Protista
Fungi
Plantae
Animalia
Bacteria - what comes to mind?
Diseases
w Infections
w Epidemics
w Food Spoilage
w Only 1% of all known bacteria cause human
diseases
w About 4% of all known bacteria cause plant
diseases
w 95% of known bacteria are non-pathogens
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Microbes Benefit Humans
1.Bacteria are primary decomposers recycle nutrients back into the environment
(sewage treatment plants)
w 2. Microbes produce various food products
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• cheese, pickles, sauerkraut, green olives
• yogurt, soy sauce, vinegar, bread
• Beer, Wine, Alcohol
3. Microbes are used to produce Antibiotics
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Penicillin
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Mold
• Penicillium notatum
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1928 Alexander Fleming
4. Bacteria synthesize chemicals that our
body needs, but cannot synthesize
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Example: E. coli
• B vitamins - for metabolism
• Vitamin K - blood clotting
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Escherichia coli
• Dr. Escherich
• Colon (intestine)
5. Biochemistry and Metabolism
Very simple structure
rapid rate of reproduction
provides “instant” data
6. Microbial Antagonism
Our normal microbial flora prevents
potential pathogens from gaining access to
our body
7. Insect Pest Control
Using bacteria to control the growth of
insects
Bacillus thuringiensis
• caterpillars
• bollworms
• corn borers
8. Bioremediation
Using microbes to clean up pollutants and
toxic wastes
Exxon Valdez - 1989
2 Genera
• Pseudomonas sp.
• Bacillus sp.
9. Recombinant DNA Technology
Gene Therapy
Genetic Engineering
Bacteria can be manipulated to produce
enzymes and proteins they normally would
not produce
• Insulin
• Human Growth Hormone
• Interferon
10. Microbes form the basis of
the food chain
Marine and fresh water microorganisms
Microbes do benefit us, but they
are also capable of causing many
diseases
Pneumonia Whooping Cough
Botulism
Typhoid Fever
Cholera
Scarlet Fever
Syphilis
Gonorrhea
Chlamydia
Tuberculosis
Meningitis
Tetanus
Strep Throat Lyme Disease
Measles
Mumps
Herpes 1
Herpes 2
RMSV
AIDS
History of the Study of
Microorganisms
1665 Robert Hooke
• “little boxes” - “cells”
• Cell Theory - all living things are made up of
cells
Anton van Leeuwenhoek 1674
- 1st person to actually see living microorganisms
“wee animalcules”
Spontaneous Generation
Theory that life just “spontaneously”
developed from non-living matter
Example:
• toads, snakes and mice - moist soil
• flies and maggots - manure and decaying flesh
Experiments to disprove
Spontaneous Generation
Francesco Redi
1668
Rudolph Virchow 1858
• Theory of Biogenesis
• Cells can only arise from preexisting cells
Louis Pasteur
1861
Pasteur designed special “swan-necked flasks”
with a boiled meat infusion
Shape of flask allowed air in (vital force) but trapped
dust particles which may contain microbes
Germ Theory of Disease
Hard for people to believe that diseases
were caused by tiny invisible “wee
animalcules”
Diseases, they thought, were caused by:
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demons
witchcraft
bad luck
the wrath of God
curses
evil spirits
Robert Koch - 1st to prove that
bacteria actually caused diseases
1876
Microbial Etiology of Infectious Disease
• etiology - the cause of a disease
Established “scientific rules” to show a
cause and effect relationship between a
microbe and a disease
• Koch’s Postulates
Koch’s Postulates
1. The same organisms must be found in all
cases of a given disease.
2. The organism must be isolated and grown
in pure culture.
3. The isolated organism must reproduce
the same disease when inoculated into a
healthy susceptible animal.
4. The original organism must again be
isolated from the experimentally infected
animal.
Exceptions to Koch’s Postulates
1. Some organisms have never been grown in
pure culture on artificial media
Treponema pallidum - Syphilis
Exceptions to Koch’s Postulates
Mycobacterium leprae
Leprosy
Never been grown in pure culture on artificial media
Abdominal cavity of the Seven Banded Armadillo
Exceptions to Koch’s Postulates
In exclusively human diseases, it is not
morally acceptable to inoculate a deadly
pathogen into a “human guinea pig”
HIV
Koch established the Microbial
Etiology of 3 important diseases
of his day
1. Cholera (fecal-oral disease)
• Vibrio cholerae
2. Tuberculosis (pulmonary infection)
• Mycobacterium tuberculosis
3. Anthrax (sheep and cattle)
• Bacillus anthracis
Anthrax
Bacillus anthracis
• Gram (+), non-motile, aerobic, spore forming rod
• Streptobacilli with central spores
• Livestock
• Sheep, cattle, goats
• Humans
• Handle hides, wool, goat hair, handicrafts from the Middle
East made from animal products
3 Forms of Human Anthrax
1. Cutaneous Anthrax
• Enters thru cut or
abrasion
• Results in painless
ulcer (1-3 cm) with
black (necrotic) center
• About 20% mortality
rate in untreated cases
2. Gastrointestinal Anthrax
• Contaminated meat
• Abdominal pain, fever,
vomiting blood, severe
diarrhea
• 25% to 60% mortality rate
3. Inhalation Anthrax
• Initial symptoms
resemble common cold
• Progress to severe
breathing problems and
shock
• Usually results in death
1-2 days after onset of
acute symptoms
• Mortality rate 99% in
untreated cases
• Treatment usually not
effective after
symptoms are present
Anthrax as a Biological Weapon
Deadly if not treated early
Spores can be produced in large quantities using basic
knowledge of biology
Spores may remain viable for years (60 at least)
Spores can be spread
• Missiles, rockets, bombs, mail, crop dusters ?
No cloud or color
No smell
No taste
Antibiotics – only effective if administered early (within
24 –48 hours)
Koch - 1st to use Agar to solidify
culture media
Golden Age of Microbiology
1857 - 1914
Pasteur
• Pasteurization
• Fermentation
Joseph Lister
• Phenol to treat surgical wounds – 1st attempt to control infections
caused by microoganisms
Robert Koch
• Koch’s Postulates
Edward Jenner
• vaccination
Paul Erlich
• 1st synthetic drug used to treat infections
• Salvarsan - arsenic based chemical to treat Syphilis
• “salvation” from Syphilis
Naming of Bacteria
Genus and species - Binomial System of
Taxonomic Classification
Information usually given:
• 1. Describes an organism
• 2. Identifies a habitat
• 3. Honors a scientist or researcher
Bacterial Morphology
Bacilli
Cocci
Spiral
Arrangements
Staphylo
Strepto
Diplo
Sarcinae
Tetrad
Vibrio
bacter
bacterium
comma shaped
bacilli
bacilli
Staphylococcus aureus
Staphylococcus
epidermidis
Streptococcus
pneumoniae
Vibrio cholerae
Rhodospirillium
rubrum
Bacillus subtilis
Micrococcus luteus
Escherichia coli
Bacillus anthrasis
Salmonella enteridis
Streptococcus
pyogenes
Steptococcus lactis
Streptococcus faecalis
Erlichia canis
Campylobacter jujuni
Helicobacter pylori
Enterobacter
aerogenes