The Life and Death of Bacteria Kelly L. Shipley

Funding and support received from…

Today’s Agenda: 1) Introduction 2) Safety 3) The Life and Death of Bacteria 4) Basic Practice Techniques 5) Surveying Different Kinds of Media 6) 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?

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