Download What Microbiology is all about

What Microbiology is all
about
The study of germs
There are 4 categories of
microbes:
Viruses
Bacteria
Yeast/Fungi
Parasites
Viruses are the smallest microbes
They are too small to be seen with a light
microscope and can only be seen with
electron microscopes. Their size range is 20300 nm
They are not capable of metabolic activity,
Must infect a living cell to reproduce.
Therefore they are not “Alive”
They can exist outside of a living environment
for a limited amount of time
This is a picture of a human
immunodeficiency virus (HIV)
Most viruses can be grown in
Tissue Culture
A tissue culture is a bottle with a single layer
of cells growing on the inside of the bottle
Virus is added to the bottle
The virus infects the cells, turning them into
virus factories
The cell fills with virus, then explodes,
releasing the virus which can be harvested
Some viruses can only be grown in
fertilized eggs
Influenza virus is one of these
Some virus caused diseases are:
Common colds
Influenza
AIDS
Hepatitis A, B, C, and D
Rabies
Measles and mumps
Smallpox
Herpes viruses (Rubella, Herpes simplex I
and II)
Influenza can cause major epidemics
In 1918 there was an
influenza pandemic that
killed 50 million people.
One fifth of the world’s
population was infected
Last winter the world faced a
new influenza epidemic
This new epidemic was the reemergence of H1N1 virus
To prepare for the new epidemic
laboratories began making H1N1
vaccine as soon as the virus was
identified, in order to have the vaccine
ready when the winter flu season hit.
Influenza still remains a serious disease
AIDS-Acute Immunodeficiency
Disease syndrome
HIV, the virus that
causes AIDS is a
new virus
It emerged in the
1970 from Africa
where it had been a
virus in monkeys
Initially it was found
in gay men, Haitians
and IV drug users
Smallpox, measles, and polio
caused their own epidemics
Smallpox caused
epidemics around the
world until a vaccine
was discovered by
Edward Jenner in
1798
In 1980 the WHO
officially declared the
whole world to be free
of smallpox
Both Measles and Smallpox were
used as biological weapons
These diseases wiped out native populations
coming into contact with them for the first
time. Both were used as biological weapons
against Native Americans during the
settlement of North America. Infected
blankets and other goods were given to the
susceptible populations and wiped them out.
Polio caused epidemics during
the 20th century until the first
vaccine was discovered in 1952
Polio caused paralysis or even death.
The disease was spread by person to person
contact like the common cold.
The Salk vaccine discovered by Jonas Salk in
1952, it was made from killed virus
The Sabin vaccine made with live attenuated
virus was discovered in 1958 and supplanted
the killed virus Salk Vaccine.
Today polio is almost unknown, even in 3rd
world countries.
Some polio patients were
paralyzed from the neck down
and spent the rest of their lives in
iron lungs
Some viruses can only be grown
in embryonic eggs
This is how influenza virus is grown
At the present time we only have
anti-viral medicines for a few
diseases.
Vaccines are available for many deadly
diseases
There are anti-viral agents that can
shorten the amount of time you are ill,
for example, Tamiflu for influenza
There is a regimen of agents that
control but do not kill the AIDS virus
Bacteria can be equally deadly
Bacteria are visible with a light microscope.
They are a few micrometers long
They are prokaryotic cells. This means that
they do not have a nucleus but their nuclear
material is distributed throughout the
organism.
They come in various shapes; rods, spheres
and corkscrews.
Most bacteria can be grown on agar
A few bacterial diseases are:
Plague Yersinia pestis
Staph infections including methocyllin
resistant staph Staphlococcus aureus
Strep throat Streptococcus pyrogenes
Gonorrhea Neisseria gonorrheae
Syphilis Treponema pallidum
Leprosy Mycobacterium leprae
Tuberculosis Mycobacterium tuberculis
The plague killed one third of the
people in Europe during the mid
14th century
Thought to have been brought to Europe by
Ghengis Khan and his horde
Spread by the fleas from black (roof) rats
An infected flea would bite a rat, the rat
would become infected and ill. Infected fleas
would leave the dying rat and bite the
inhabitants of the house.
Death in humans would occur within x
number of hours. As the disease spread, it
modified so that there was human to human
spread.
How plague spread
Syphilis was brought to the old world
from the new world by Columbus
and the explorers who came after him
The first outbreak in Europe occurred during
the War of Naples in 1494
When this disease first came to Europe it
caused disfiguring lesions all over the face of
victims, and they often died within 3 to 4
months.
The disease has become less virulent in the 5
centuries since then, and now causes a chronic
disease that can be treated, but if untreated,
will not kill the patient for 20 to 50 years.
Syphilis has 3 stages, the first stage
is infectious and the 3rd (and final)
stage is neurological
Famous people who had Syphilis:
Napoleon Bonaparte, King Henry VIII of
England, Karin Blixin (wrote Out of
Africa) Vincent Van Gogh, Al Capone,
Paul Gauguin, Tsar Ivan the Terrible,
Oscar Wilde, Leo Tolstoy, Fredrick
Nietzche and the captain of the Pinta
(one of Columbus’s boats)
An image of Treponema
pallidum: this bacterium is called
a spirochete.
Most bacteria can be grown on
agar plates
This picture
demonstrates several
different bacteria
growing on blood agar
You can see white
colonies, some green
colonies and some that
clear the agar. These
are all different
organisms
Most bacteria can be seen through a
light microscope
This is what
staph
bacteria look
like with a
light
microscope.
Bacteria come in different shapes
They may be rod shaped
They can be round and grown in
clusters
They can be round and grow in long
chains
They may be corkscrew shaped like the
spirochete that causes syphilis
Images of rod shaped bacteria
and bacteria in chains
Most bacteria are susceptible to
antibiotics, which have been
available since the 1940s
Antibiotic: anti means against, biotic means
life. Early antibiotics were made from molds
that killed bacteria
In 1928 Alexander Fleming discovered that
the mold penicillium would kill staphlococcus
Modern antibiotics are no longer made from
molds but are discovered in laboratories.
This is what Alexander Fleming saw
when he discovered penicillin
Yeast/fungal diseases
Yeast and Fungal diseases range from:
Annoying and commonplace like
ringworm, athletes foot and yeast
infections
To deadly difficult to treat diseases such
as Histoplasmosis, Cryptococcosis and
Coccidiomycosis
Yeast and fungi are eukaryotic
cells
They contain a nucleus
And a cell wall like plants do
They belong in the Fungi kingdom
which is separate from the kingdoms of
plants, animals, and bacteria
Pictures of a budding yeast and of a fungus
Yeast and fungi can be cultured
much like bacteria
Minor fungal diseases such as
ringworm and fungal nail infections
Life threatening yeast/fungal
infections
Fighting fungal infections
There are anti-fungal drugs
Most are toxic
Most fungal infections take a long time
to treat
The failure rate for anti-fungal drugs is
high
The fourth group of microbes is
parasites
There are protozoans, one cells animals such
as amoebae which cause diseases as diverse
as dysentery and malaria
Malaria is an amoebic disease
carried by mosquitoes
One million people die
from it each year mostly
children under the age
of 5
There are 250 million
cases per year
Most of the cases are in
sub-Saharan Africa
3.3 billion people live
where malaria is a
threat
Helminths are worms and flukes
Helminthic diseases include
Tapeworms
such as fish,
pork and beef
tapeworms
Flukes of the
blood, liver and
lungs
Roundworms
like hookworms
and pinworms
The size range of parasites
Amoeba 10-20
micrometers
Roundworms
0.5mm to 1 cm
Flukes 5mm to
several cm
Tapeworms 1mm
to 15 m (50 feet)
There are both anti amoebic and
anti helminthic drugs,but there is
not treatment for all amoebic or
helminthic diseases.
Normal Flora
All living organisms have viruses,
bacteria, yeast/fungi and parasites
living on them and in them
In a healthy organism these microbes
are beneficial
The normal flora varies from organism
to organism
Normal flora varies according to
the site and the organism
Not all humans have the same flora
It varies according to where you live
and what you are exposed to
It varies according to the part of the
body. Organisms that live on your skin
are different from those in your mouth
or in your intestines.
Some parts of your body are
sterile—without normal flora
Blood
Brains
Muscle
bones
The End