Antibiotics

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Antibiotics Bacterial Resistance
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Antibiotics

• Are natural substances that stops or destroys
  microorganisms by attacking metabolic pathways in
  the bacteria
• Example
• penicillin which works by preventing bacteria
  from constructing a normal cell wall
• Streptomycin works by preventing bacteria from
  manufacturing proteins

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The first antibiotic

• 1928 discovered by accident Alexander Fleming
  in
• St. Mary's Hospital, London (UK)
• He received the Nobel Prize in Medicine in 1945
  along
• with his two colleagues

• He noticed a ring of inhibition of bacterial
  growth around a contaminant blue-green mould on a
  Staphylococcus plate culture.

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The first antibiotic

• He then concluded that the mould was releasing a
  substance that was inhibiting bacterial growth
  and lysing (killing) the bacteria.
• He grew a pure culture of the mould and
  discovered that it was a Penicillium mould, now
  known to be Penicillium chrysogenum.

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Age of Antibiotics

• Since the 1940s researchers have identified more
  then 2500 naturally occurring antibiotics that
  can be used to treat infections
• However, over the 50 years since, many
  disease-causing bacteria have become slowly
  resistant to the antibiotics

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Antibiotic resistance

• Initially when a antibiotic is introduced into a
  system it kills off the weaker strains of
  bacteria
• This leaves behind the strong strains
• These strong strains have slight variations
  within their genetic material which allow
  then to survive the antibiotic

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These strong bacteria reproduce to pass on their
strong fighting ability
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Antibiotic use in animals

• A large percentage of antibiotics produced are
  used in livestock production in 3 ways
• Therapeutic doses to treat disease
• Preventative doses to reduce risk of disease or
  death during production
• Low dose added to feed to promote growth

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Non-therapeutic use of antibiotics in farm
animals is a good or bad thing?

• Take 5 minutes and discuss with the person beside
  you whether its a good or bad thing to add
  antibiotic to livestock feed

Think about production rates, consumer thoughts,
price of meat at the store, health of animals
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What do you guys think?