Human Health and Disease Bacteria and Viruses

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Human Health and DiseaseBacteria and Viruses
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Bacteria

• Characteristics
• Prokaryotic
• Kingdom Monera
• Single-celled organism with no membrane-bound
  organelles
• Reproduce asexually
• Components Cell wall, Cell membrane, cytosol,
  ribosomes and DNA plasmids. Some have cilia or
  flagella for movement

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Gram-positive Bacteria
Types of bacteria

• Possess a thick peptide layer which retains a
  stain called crystal violet. Appear purple when
  viewed under a microscope.

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Gram-negative Bacteria

• have a thin peptide layer, take up the pink
  stain, and appear pink when viewed under a
  microscope.

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Shapes of bacteria Bacillus (rod-shaped), Cocci
(round), Spirillum (corkscrew-shaped)
Bacillus Example Anthrax
ispub.com
nanopatentsandinnovations.blogspot.com
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Cocci Example streptococcus (causes strep
throat)
medschool.lsuhsc.edu
hardinmd.lib.uiowa.edu
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Spirillum/Spirochetes Example Treponema
pallidum- causes syphilis
www2a.cdc.gov
www2a.cdc.gov
www.kellykite.com
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How Bacteria Cause Disease

• Metabolizing the host-
• Heterotrophic bacteria obtain nutrients by
  secreting enzymes that break down organic
  structures and absorb them
• If the environment is your throat or lungs, this
  can cause serious problems!
• Ex.
• Tuberculosis bacteria settle into the lungs and
  use human tissue as their nutrients
• Propionibacterium acnes causes acne

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• Toxins-
• Some bacteria secrete chemical compounds into
  their environment which are poisonous to
  eukaryotic cells (toxic)
• Ex. Diptheria grows in the throat, but the toxins
  attack the heart, nerve, liver and kidneys
• Food poisoning occurs when humans eat food where
  bacteria have grown and produced toxins

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What can you do?

• Protect your food
• Heat
• Freeze
• Dry

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Evolution of Antibiotic Resistance

• Forty or fifty years ago, thanks to antibiotics,
  scientists thought medicine had all but
  eradicated infectious agents as a major health
  threat.
• More recently, an upsurge of infectious disease
  is a problem we have unwittingly created for
  ourselves b/c
• rapid, frequent, and relatively cheap
  international travel allows diseases to leap from
  continent to continent
• Many people have inadequate sanitation and lack
  of clean drinking water
• We have overused the "miracle drugs to treat
  such diseases to the point that they lose their
  potency

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• Whenever antibiotics wage war on microorganisms,
  a few of the enemy are able to survive the drug.
• Because microbes are always mutating, some random
  mutation eventually will protect against the
  drug.
• Antibiotics used only when needed and as directed
  usually overwhelm the bugs.
• Too much antibiotic use selects for more
  resistant mutants.
• When patients cut short the full course of drugs,
  the resistant strains have a chance to multiply
  and spread.

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