Microbiology in a Nutshell
Yes, you will need to know this
Microbes
Ever wonder why Robin Williams is hirsute,
while Patrick Stewart is follecularly
challenged? Well, the answer is in their
DNA-
Viruses
• Microscopic (can’t see with the naked eye)
• nonliving particle
• Invades and reproduces inside a host.
• Contains DNA or RNA
The red spots are
the AIDS virus, they
are surrounding
other body cells.
Virus Multiplication
• Active
– Become sick within hours or days
• Hidden
– Illness can be delayed for weeks, months, or
years
– Triggered by environment?
Bacteria
• Microscopic
• Prokaryotes (means they don’t have a
nucleus)
• Living
• Contains DNA
Shapes of bacteria
• Spherical
• Rodlike
• Spiralshaped
• They can also be in chains
– Spherical chain
Bacteria Multiplication
• Sexual reproduction
– Two parents
– Conjugation (transfer of genetic material
through bridge)
• Asexual reproduction
– Binary Fission-Simply splitting in two
Growth in Action
More on Growth
• Rapid, as fast as once
every 20 minutes
• Continues until they
run out of the basics
– Food
– Air
– Space
Parasites
• Organisms that live on or in a host and
cause harm.
• Examples: Viruses, Bacteria, and
tapeworms.
• Can a bacteria be a host?
How many can there be?
• These bubble-headed creatures
are called bacteriophages,
viruses that target bacteria. The
head holds DNA and the tail
acts as a needle attaching to a
specific site on the bacterial cell
wall, the virus squirts DNA
through the tail into the
bacterium. Ouch! They are
among the smallest of
organisms. You could fit about
680,000 of these creatures on
the head of a pin.
What can you do?
• Get Vaccines
• Personal Hygiene
• Use Disinfectants
• Lines of Defense
– Skin
– Mucus barriers
– Immune System
Defenses cont. .
This is a human macrophage, found in your
blood that wards off infection. It is homing in
on a chain of nasty Streptococcus bacteria.
Hitching a ride aboard the macrophage is a
sphere-shaped lymphocyte. Both macrophage
and lymphocyte can be found near the site of
an infection, and the two act in concert to help
eliminate it.
The deadliest pandemic in history was the 1918
influenza epidemic, the Spanish Flu. By the time the
"Spanish lady" departed, 22 million people had died of
the mysterious killer.
Positively identifying the 1918 flu
strain is made more difficult by the
fact that the flu virus is capable of
very rapid mutations
Personal example
• A doctor stationed at
Camp Devens, a military
base just west of Boston,
writes to a friend, and
fellow physician, of the
conditions to be found
there as influenza was
making its presence felt.
Vaccines
Existing flu shots are 70
percent to 90 percent
effective at preventing flu
in healthy young people
• 50 percent effective in the
elderly, (And even if the
vaccines don't prevent the
flu, they do tend to reduce
symptoms and serious
complications).
High Risk Groups
• aged 65 and older
• with chronic diseases
affecting the heart, lung or
kidneys
• with diabetes,
immunosuppression, or
severe anemia
• people in contact with
doctors, nurses and
nursing-home staff
Prevention
• "The current U.S. plan in
the event of a pandemic is
to vaccinate virtually the
entire population," says
epidemiologist Nancy
Arden.
• Despite its advantages, less than
60 percent of the high-risk
population gets the flu shot
each year.