Bacteria are Everywhere

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Bacteria are Everywhere

• By Lauren Senter
• Dr. Hamrick
• STEP Program at Campbell University

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Overview

• Part 1
• Places we find bacteria
• Identification
• Part 2
• Control
• Part 3
• Detection in drug products

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Places we find bacteria

• Hands
• Throat
• Nose
• Food

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Hand Washing Experiment

• This experiment shows how bacteria normally lives
  on your skin. When you wash your hands, you
  remove the surface bacteria that can make you
  sick but it will not kill or remove all the
  bacteria on your skin.
• To do this experiment
• Make imprint of hand on an agar plate before
  washing hands.
• Then make an imprint of hand after washing hands
  thoroughly with soap and water.
• Incubate until the bacteria grows.

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Bacteria in the Throat

• For this experiment, we were able to look at and
  see the different types of bacteria in the
  throat.
• To do this experiment
• Gently rub the back of throat with a sterile
  cotton swab.
• Then rub the bacteria onto a rich media.

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Bacteria in the Nose

• In this experiment, we were looking for a
  specific kind of bacteria.
• In this experiment
• Using a sterile cotton swab, gently rub the
  inside of one nostril.
• Then rub the bacteria onto an agar plate and
  incubate for 2 to 3 days.

Mannitol Salt agar
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Bacteria in Food

• In this experiment, we were looking for different
  types of bacteria in the foods we might eat.
• To do this experiment
• Grind up alfalfa sprouts into a fine liquid.
• Plate dilutions of the liquid, and incubate to
  grow up the bacteria.
• One of the plates was labeled TNTC (or too
  numerous to count).The other plate had a total of
  165 colonies
• 82,500,000 bacteria in a gram of alfalfa sprouts.

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Identifying Bacteria

• When we find bacteria, there are a number of ways
  to find out what kinds of bacteria we have.

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Gram positive
Gram negative
Cocci (spheres)
rods
Cocci (spheres)
rods
Easy to grow
Hard to grow
Bacillus subtilis
Cells in chains catalase negative Streptococcus
pneumoniae
E. coli
Haemophilus influenzae
Cells in clusters catalase positive Staphylococci
Flow chart for identifying microorganisms
Coagulase positive Staphylococcus aureus
Coagulase negative Staphylococcus epidermidis
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Identifying Bacteria

• Gram Staining is the first step in figuring out
  what kind of bacteria you are dealing with.
• Gram Staining determines whether the bacteria is
  gram positive, which consists of a cell membrane
  and a thick cell wall, or gram negative, which
  consists of an inner membrane, a thinner cell
  wall, and an outer membrane.

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Dont Mess Up!

• It is important for the bacteria to be a pure
  culture before putting in a test tube or running
  any test.
• Single colony purification
• If you have a mixture of bacteria when you run
  biochemical test they might appear positive even
  if some bacteria are negative.
• It will cause you to mess up when classifying the
  bacteria.

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Catalase Test

• Hydrogen peroxide is a good chemical for killing
  bacteria.
• Catalase is a bacterial enzyme that converts
  hydrogen peroxide into water and oxygen.
• To do this experiment
• Use a loop to remove a little bit of bacteria
  from the plate and smear it onto a microscope
  slide.
• Add 1 drop of hydrogen peroxide. If the organism
  produces a catalase, rapid bubbling will occur.
• This test helps to recognize if the gram
  bacteria is Streptococci or Staphylococci.

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Coagulase Test

• We did a third test to determine if the bacteria
  were coagulase positive or coagulase negative.
• Coagulase is a bacterial enzyme that clots (or
  coagulates) plasma products.
• This test would tell us if the Gram , catalase
  , bacteria were Staphylococcus aureus or
  Staphylococcus epidermidis.

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Clinical sample
Gram positive
Gram negative
Cocci (spheres)
rods
Cocci (spheres)
rods
Easy to grow
Bacillus subtilis
Hard to grow
Cells in chains catalase negative Streptococcus
pneumoniae
E. coli
Haemophilus influenzae
Cells in clusters catalase positive Staphylococci
Flow chart for identifying microorganisms
Coagulase positive Staphylococcus aureus
Coagulase negative Staphylococcus epidermidis
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Control

• Bacteria in the wrong place can make us sick,
  therefore we have several ways to eliminate or
  control bacteria.
• Some of the ways we can control bacteria are
• Antibiotics
• UV light

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Antibiotics

• Antibiotics kill bacteria.
• Different bacteria show different
  susceptibilities to different antibiotics.
• To do this experiment
• Lay little discs with antibiotics in them on
  plates inoculated with bacteria.
• Incubate and you are able to see the different
  susceptibilities of the bacteria to the medicines.

Resistant
Sensitive
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UV Light

• UV light damages bacterial DNA. Different
  bacteria have different susceptibilities to UV
  Light.
• To do this experiment
• Swab half of each of 4 plates with a
  spore-forming bacteria, and the other half with a
  non-spore forming bacteria.
• Place one plate (marked 0 min) into the
  incubator. Place the remaining plates into the
  hood under the UV light with their lids off.
  Place the sunglasses over the plate labeled 5min.
• Leave the plates in the hood for the allotted
  time, then take them out and put them into the
  incubator.

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Results

• 0min. All bacteria grew.
• 1min. Bacillus subtilis is able to form spores.
  Spores are more resistant to UV damage, but some
  of the bacteria were killed.
• Without the ability to produce spores most of the
  bacteria in the lower part of the plate were
  killed by the UV light.
• 3min. A little more of the Bacillus continues to
  die off. The non-spore forming bacteria is almost
  completely dead.
• 5min. Most of all bacteria are dead except for
  where the sunglasses were sitting.The sunglasses
  protected both kinds of bacteria from the UV
  light.

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Detection

• To do this experiment
• Grow up Bacillus subtilis as your test bacteria.
• Generate a growth curve and add small amounts of
  bacteria to the media.
• The plan was to then add small amounts of
  Bacillus to a drug preparation and pass through
  the filter.
• Then add media to the filters and wait for the
  growth of the bacteria.

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Steritest

• Add drug preparation (containing bacteria) to the
  filter unit
• Add media and incubate
• Each filter unit in this test received 2.4 x 104
  bacteria.

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Sum Up

• From doing these experiments, I have learned that
  bacteria are everywhere and sometimes they
  belong sometimes they dont!