The Life and Death of Bacteria
Kelly L. Shipley
Funding and support received from…
Today’s Agenda:
1)
2)
3)
4)
5)
6)
Introduction
Safety
The Life and Death of Bacteria
Basic Practice Techniques
Surveying Different Kinds of Media
Closing
Introduction:

All living things contain
cells

Eukaryotes: more than
one cell

Prokaryotes: one cell
organisms
The Boring (Yawn!!) Eukaryotic Plant and
Animal Cells…
The Exciting Bacterial Cell…
What are Bacteria?

Bacteria are prokaryotes, meaning they are only
ONE celled organisms. They are very small and can
be harmful or beneficial.
Follow along…

You have a picture of a bacterial cell at your
desk.

Follow along with the following diagram,
making sure you understand what each
structure is and how it works.
Bacterial Cell Components…
Bacteria come in many different
shapes and sizes…take a quick look…
How big are bacteria?

How many bacteria will fit on the head of a
pencil, like the one you use every day??
1 MILLION bacteria
could fit onto the tip
of that one pencil!!
Bacteria can replicate easily…

To grow, bacteria divide and
divide and divide again.

Problem: If you started with only 1
bacteria cell, and it divided 10 times,
how many bacteria would you then
have??
Bacteria are everywhere…
Don’t panic!!
This is a good thing.
Bacteria are part of our lives, our
ecosystem and our habitat!
Bacteria can cause diseases, like we
all know…
Bacteria can also have beneficial
uses…
As well as those beneficial uses…

There are many bacteria which humans need
every day.

They live on us and in us and we NEED
them!!!

They are called our “NORMAL FLORA”
Normal “flora”

Flora – microorganisms that are
usually found associated with
healthy body tissue

What does that mean?
Normal flora are bacteria which
our body needs and play a “good”
role to help us stay healthy.
Let’s look at the different areas
“flora” live…
and then we will test
them!!
Normal flora of the skin

Skin is considered a “harsh”
environment for bacteria, why?

Bacteria like the areas of the skin
which are moist; underarms,
sweat glands etc.

Most are not harmful, but Acne…

Ie: Staphylococcus,
Propionibacterium acnes,
Normal flora of the oral cavity

Streptococcus is a normal
bacteria in your mouth

Other bacteria are also present
that turn sugars into acids and
cause dental plaque, cavities
and decay

Brushing our teeth allows the
normal flora to grow without
build-up of other bacteria!!
Normal flora of the GI tract

The GI tract is the stomach,
small intestine and large
intestine.

Several different types of
bacteria live in the GI tract
and aid in digestion,
movement of waste and
absorption.

Ie: E. coli, Clostridium,
Enterococcus faecalis,
Normal flora of the Urogenital Tract

Urethra (tube from which you
urinate) have normal
microorganisms present, but
they can become “opportunistic”
when there is a change in the
environment and causing
infection

Bladder and reproductive organs
should always be sterile
Normal flora of the Respiratory Tract



Upper: oral cavity and throat
microorganisms live in the
areas around mucous
membranes
Ie: Staph, Strept, and some
gram negative
Lower: trachea, bronchi and
lungs should ALWAYS be
sterile, if not – pneumonia
Lab Information…Pay Attention


The following is an
introduction to some
of the media we will
be using today…
Pay attention!!
Different Kinds of Media

We “grow” bacteria on different
types of media.

“Media” means an
environment inside a Petri dish
that has certain characteristics

We will go over the types of
media we are using today
MacConkey Agar Media

MacConkey is
specifically designed to
help bacteria that live
on the skin to grow

“Gram Positive”
bacteria

Grows pink, purple and
white colored colonies
Mannitol Salt Media

Mannitol Salt is specifically
designed to help “gut”
organisms grow.

“Gram Negative” bacteria

Yellow = gut organisms
present
No change = no gut
organisms present
Nutrient Agar Media

Nutrient media is NOT
selective (G+ and G-)

This means that most all
bacteria LOVE to eat
nutrient agar

It is the most common
media, and we will be
using it A LOT!!
Now, let’s move on to our lab protocol.

We will be surveying different places where
the different “skin” and “gut” bacteria grow

Where would be some good places to find
either?

Where are some places to find them, where
they really SHOULDN’T be?
Anti-Microbial Testing

Goal: To see how the
products we use in our
homes affect the
different bacteria we
know are around.

What types of products
are out there?
Disinfectants

Disinfectants are
substances that inhibit
bacterial growth

THEY ARE ALSO
HARMFUL TO HUMAN
TISSUES!!
Disinfectants

Disinfectants are
substances that inhibit
bacterial growth

THEY ARE ALSO
HARMFUL TO HUMAN
TISSUES!!
Disinfectants

Disinfectants are
substances that inhibit
bacterial growth

THEY ARE ALSO
HARMFUL TO HUMAN
TISSUES!!
Antiseptics

Antiseptics are
chemical substances
that inhibit bacterial
growth

THEY ARE NOT
HARMFUL TO HUMAN
TISSUES
Antiseptics

Antiseptics are
chemical substances
that inhibit bacterial
growth

THEY ARE NOT
HARMFUL TO HUMAN
TISSUES
Antiseptics

Antiseptics are
chemical substances
that inhibit bacterial
growth

THEY ARE NOT
HARMFUL TO HUMAN
TISSUES
What do you think?

Will antiseptics, which we use
on our bodies, be more
effective on Gram pos. or
Gram neg. bacteria?

What about disinfectants?

How do each do against the
bacteria on our plates?
How do you get your results?

Call me at 503-838-8209

E-mail me at shipleyk@wou.edu

Go to our website at www.wou.edu/