Antibiotics

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Antibiotics

• Biology Presentation

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Antibiotics

• About Antibiotics
• About Antibiotic Resistance
• Something we should know when we take antibiotics

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About Antibiotics What is antibiotics?

• Chemical Compounds
• Able to kill or inhibit the growth of bacteria
  (e.g. human) without causing significant damage
  to the host
• Naturally produced (e.g. penicillin) by mold or
  bacterium, or
• Synthetically made (e.g. fluoroquinolones)

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About AntibioticsDiscovery of antibiotics

• In 1929, first discovered by British Scientist
  Alexander Fleming.

• However, he could not purify the compound due to
  its instability.
• Until the period of World War II (1939-1945), two
  other British scientists, Florey and Chain
  successfully managed to produce antibiotics in
  industrial scale for widespread use.

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About AntibioticsHow do antibiotics work?

• Bacteriostatic antibiotics (e.g. Penicillin)
• Not actually kill the bacteria
• Stop the cells from growing and multiplying
• Allows time for the infected host to mount an
  immune response ? Eliminate the non-growing
  infectious agent (i.e. the bacteria)

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About AntibioticsHow do antibiotics work?

• Bacteriocidal antibiotics
• Actually kill the bacteria
• Preferred choice when the patients immune system
  is weakened or incapable of destroying the
  organisms itself

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About AntibioticsHow do antibiotics work?

• In both cases, bacteriostatic and bacteriocidal
  antibiotics disrupt the bacterial cells by
  attacking
• the outer cell wall or inner membrane, or
• the chemical pathways necessary for the bacteria
  to live or reproduce.
• NO activities against most of the viruses.

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About AntibioticsHow do antibiotics work?

• E.g. Penicillin
• Prevents the cross-linking of small peptide
  chains in the main cell wall polymer of bacteria.
• Pre-existing cells are not affected.
• All newly produced cells grow abnormally
• Unable to maintain cell wall rigidity

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About AntibioticsHow are antibiotics used?

• In medical ways
• ? to treat illness caused by bacteria
• ?to prevent bacterial infections in surgery
• In the supply of food
• ?to increase the growth of certain
• food animals
• ?used as pesticides to control
• bacterial infections in food crops.

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About Antibiotics ResistanceWhat is antibiotic
resistance?

• An antibiotic lost its ability to effectively
  control or kill bacterial growth.
• i.e. bacteria are resistant and continue to
  multiply in the presence of therapeutic levels of
  and antibiotics

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About Antibiotics ResistanceWhy do bacteria
become resistant to antibiotics?

• Natural phenomenon

4. Eventually there are more antibiotic-resistant
bacteria than non-resistant.
2. The bacteria with resistance survive after the
antibiotics are gone.
3. ....and reproduce, inherit the resistant genes
to their offspring.
1. Antibiotics attack and kill off bacteria
without resistance.
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About Antibiotics ResistanceWhy do bacteria
become resistant to antibiotics?

• Resulting in the survival of resistant strains of
  bacteria.? survival for the fittest ? Natural
  Selection
• Low-level of natural selection ? produced by
  bacteria to against each other (w/out human
  action)
• High-level of natural selection ? by overuse of
  antibiotics (human action)

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About Antibiotics ResistanceHow do bacteria
become resistant?

• By genetic mutation
• Chance 1 / 1,000,000 10,000,000
• ? produce enzyme to inactivate the antibiotics
• ? eliminate cell target that the antibiotic
  attacks

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About Antibiotics ResistanceHow do bacteria
become resistant?

• By acquiring resistance from another bacterium
• ? by conjugation
• Bacteria have the ability to collect multiple
  resistant traits over time ? resist to many
  different families of antibiotics

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About Antibiotics ResistanceHow does antibiotic
resistance spread?
Vertically ? new generations inherit antibiotic
resistance genes.
Horizontally ? share or exchange genes with
other bacteria , even occur between different
species.
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About Antibiotics ResistanceHow does antibiotic
resistance spread?

• Environmentally
• Via airplane, water and wind, coughing, or
  contact of unwashed hands.

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About Antibiotics Resistance Can bacteria lose
their antibiotic resistance?

• YES
• Slow process
• Stop using antibiotics for a while ? the
  population of bacteria that responds to
  antibiotics increases

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Something we should know when we take antibiotics

• Antibiotics may cause side effects
• (e.g. nausea, diarrhea and stomach pain)
• In some people, an allergic reaction
  (characterized by rash and itching or in severe
  cases, difficulty breathing) can occur
• Should only be used when prescribed by your doctor

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Something we should know when we take antibiotics

• must be taken for the full amount of time
  prescribed by your doctor
• should not be saved and reused

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Please Take Care (o_o)
Presented by 6B Law Wei Bong
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Reference URL

• AUPA Alliance for the Prudent Use of Antibiotics
• http//www.healthsci.tufts.edu/apua/apua.html
• Medem Inc.
• http//www.medem.com/medlb/article_detaillb.cfm?ar
  ticle_IDZZZPT86928Csub_cat277
• Medline plus
• http//www.nlm.nih.gov/medlineplus/antibiotics.htm
  l
• The Microbial World
• http//helios.bto.ed.ac.uk/bto/microbes/penicill.h
  tm
• Stalking the Mysterious Microbe
• www.microbe.org/microbes/ mutations.asp