Bacteria: the good, the bad and the ugly

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Bacteria the good, the bad and the ugly

• Anne Todgham and Annick Gauthier
• University of British Columbia

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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
• Cant kill virus with antibiotics

Rod-like Bacteria
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Pictures of Bacteria
Bacteria from Fish
Anthrax
Anabena
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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!

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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

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Why we should love bacteria

• 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

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Why bacteria love us
Our bodies provide bacteria with

• Constant supply of nutrients
• Stable environment and constant temperature
• Protection
• Transportation

We are a great home to live in!!
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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.

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More cool bacteria numbers

• 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

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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

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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

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Materials and Methods

• Objective to culture bacteria from around the
  classroom and your body
• Materials 1 LB agar plate, 4 cotton swabs,
  pencil and paper to take notes, marker
• Method
• 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

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Pictorial of Procedure
Next class
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Growing Bacteria

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

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Culturing Bacteria
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Identification of Bacteria

• Grow bacteria on different media
• Different bacteria grow on different types of
  plates
• Check for antibiotic resistance
• Jessicas expt
• Use stains or antibodies
• Gram stain
• Antibodies agglutinate
• Clump up bacteria
• DNA
• amplify certain genes

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How do we defend ourselves?

• Non-specific
• Skin
• Hair
• Shedding cells
• Tears
• Macrophages
• Good bacteria!
• Specific
• Antibodies
• B cells
• T cells

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Picture of Gastrointestinal Tract
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Bacteria 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

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Picture of Respiratory System
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Life 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

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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