Bacteria: the good, the bad and the ugly

Anne Todgham and Annick Gauthier

University of British Columbia

What are bacteria?

Small organisms - several µm (1/1000 of a cm, can only see 1/100)

They have all they need to live DNA Energy Food Can make proteins

Good and bad bacteria!!!!!! Bacteria can be killed with

antibiotics Viruses are different - need host

to “live” Can’t kill virus with antibiotics Rod-like Bacteria

Pictures of Bacteria

Anthrax

Anabena

Bacteria from Fish

Where are bacteria?

On our skin In our intestinal tract

Help us digest food In our mouth, throat In the soil In the ocean In the forest On plants Everywhere!

Good vs Bad

Some bacteria cause disease meningitis pneumoniae diarrhea

Good bacteria too: for example E. coli there are disease-causing strains there are digestion-helping strains

Why we should love Why we should love bacteriabacteria

Live happily in the guts and lungs of animals aid in digestion of food and vitamin production stimulate the growth of some of our tissues

Fight foreign disease causing bacteria and prevent them from infecting us

Important in the cycling of nutrients in the environment ex. nitrogen and carbon

Make up the bottom of most food webs critical for the survival of most living organisms thought to be the origin of multicellular organisms

Our bodies provide bacteria with:

We are a great home to live in!!We are a great home to live in!!

Why bacteria love us

Constant supply of nutrients Stable environment and constant temperature Protection Transportation

Interesting tidbits 1013 bacteria in/on human body, and only 1012

human cells 109 bacteria per gram of feces (population of

world) Only a very small number of “bad” bacteria We breathe in 3-4 bacteria per breath Number one infection: cavities 50% of worlds population dies of infectious

diseases (20% in our society) Infectious diseases are the leading cause for

taking time off of work More people died in the Civil War of infectious

disease that by bullets.

More cool bacteria More cool bacteria numbersnumbers

Oldest fossil known is bacteria-like organisms that are 3.5 billion years old!!

100 000 bacteria in each cm2 of skin 1 billion bacteria in a teaspoon of soil 80 distinguishable species of bacteria living in the mouth

alone Greater than 200 species of bacteria living on the entire

body Can reproduce every 20 min

Uses for Bacteria

Production of antibiotics like streptomycin and nocardicin

Put the tang in yogurt and the sour in sour cream Vaccination (dead or weak bugs used to boost

our immune system) Can be used to break down oil after an oil spill

Growing Bacteria All the bacteria that we will grow are normal

bacteria that do not cause disease Bacteria grow in colonies on a substance called

agar that contains sugars and salts We have poured these agar plates for you

CONDUCT EXPERIMENT Incubate plates at 37oC at UBC for 2 days Plates will be stored in fridge until October 23

when we will return to discuss results with you

Materials and MethodsObjectiveObjective: to culture bacteria from around the classroom and

your body

MaterialsMaterials: 1 LB agar plate, 4 cotton swabs, pencil and paper to take notes, marker

MethodMethod:

1. Using black marker, divide plate into 4 quadrants, label plate with your name and the date in small letters

2. Choose which 4 areas you will swab and record this in your science duotang

3. Label the plate with the areas you will swab note label the bottom (i.e. agar containing part of the

plate)

4. Remove one sterile swab from its packaging (do not touch it), swab area of choice by gently rubbing cotton swab on it, and then transferring this to the LB agar plate by gently rubbing the agar in the designated quadrant

5. Repeat step 4 for 3 other areas of choice

6. Clean up: put LB plate and marker into middle of your table, put all cotton swabs and wrappers into orange garbage bag

Pictorial of Procedure

Next class:

Growing Bacteria thumb mouth, nose or ear floor table phone keyboard light switch sink sink faucet toilet handle toilet

Culturing Bacteria

Identification of Bacteria

Grow bacteria on different media Different bacteria grow on

different types of plates Check for antibiotic

resistanceJessica’s expt

Use stains or antibodies Gram stain Antibodies “agglutinate”

Clump up bacteria DNA

amplify certain genes

How do we defend ourselves? Non-specific

Skin Hair Shedding cells Tears Macrophages Good bacteria!

Specific Antibodies B cells T cells

Picture of Gastrointestinal Tract

Bacteria of the mouthBacteria of the mouth

Dental plaque, cavities and periodontal disease result from the actions initiated by our normal bacterial flora

60-70% of the volume of plaque is made of bacteria -- these bacteria release lactic acid that breaks down the enamel of the teeth and can cause cavities and further infection of your mouth

Picture of Respiratory System

Life without bacteriaLife without bacteria

Normal bacterial flora are very important in protecting our bodies from pathogenic or disease-causing bacteria

Administration of broad-spectrum antibiotics has a profound effect on our “good” bacteria and can result in “bad” antibiotic-resistant bacteria infecting our bodies

Animals raised in an environment filled with bacteria are much healthier than those raised in a sterile environment

Clean hypothesis People need bacteria to live

How can we stay healthy?

Good nutrition Low stress Age Cleanliness

but we need bacteria antibacterial soaps

Regular doctor and dental visits

Vaccines up to date