Microbiology introduction

• Robert Hooke (1635-1703)

  • Developed the first compound microscopes (x20 – x50)
  • Published ‘Micrographia’ in 1665
  • First to use phrase ‘cells’ when observing the stem of the cork plant
• Anthonie van Leuwenhoek (1662-1723)

  • Simple microscope (x200)
  • Developed for examining cloth
  • Wrote to the Royal Society in London in 1673 observing ‘Animalcules’ in a drop of drain water
• miasma theory

  • Hippocrates 400 BC (Europe)
  • Believed that diseases were spread from ‘bad air’ and vapours from decomposing matter
• spontaneous generation theory

  • Life arises spontaneously from non-living materials
  • Francesco Redi (1668)
  • First to refute spontaneous generation with a meat experiment
• washing hands theory

  • Ignac Semmelweiss (1818 – 1865)
  • Found that doctors washing their hands with chlorinated lime solution led to a drastic decrease in death rates in birth ward
  • “Cadaverous particles”
• Louis Pasteur (1822-1895)

  • Demonstrated that heat could sterilise media
  • Pasteur flask experiment showed that particulates necessary for contamination (1864)
• Robert Koch (1834 - 1910)

  • First experimental evidence that microorganisms cause disease
  • Demonstrated transmission of anthrax in animals
  • Discovered Mycobacterium tuberculosis as the cause of tuberculosis
  • Koch’s postulate remains ‘gold standard’ in medical microbiology
  • Not always possible to satisfy all postulates for every infectious disease
• Koch’s Postulate (1876)

  1. the suspected pathogenic organism must always be present in animals suffering from the disease and should not be present in healthy individuals
  2. the organism must be cultivated in pure culture away from the animal body
  3. cells from a pure culture of the suspected organism shoulf cause disease in a healthy animal
  4. the organism should be re-isolated and shown to be the same as the original
• Joseph Lister (1827 – 1912)

  • Postulated that surgical infections caused by microorganisms
  • Introduced aseptic techniques for surgery in 1876
  • Dramatic reduction in sepsis
• Martinus Beijerinck (1851-1931)

  Enrichment media and selective plates used routinely in modern microbiology diagnostic labs

  
• Paul Ehrlich (1854 – 1915)

  • Searched for chemicals (magic bullets) that would kill a microorganism but leave host unaltered
  • Discovered Salvarsan for the treatment of syphilis 1910
• Alexander Fleming (1881 –1955)

  • Discovered that Penicillium notatum prevented growth of Staphylococcus aureus
  • Awarded Nobel prize in 1945 with Chain and Florey
• Edward Jenner (1749 – 1823)

  • Noticed that milkmaids with cowpox did not become infected with smallpox during an outbreak in Gloucestershire (1788)
  • Took material from pustules of milkmaids and inoculated into a child
  • 1798 – published ‘An inquiry into the causes and effects of the Variolae vaccinae’
• Modern Vaccination

  • Killed whole organisms
  • Attenuated
  • Protein components
  • RNA vaccines (COVID-19)
• Biotechnology and Synthetic Biology

  Using microbes to detoxify environments and to produce medicines (“Biologics”), materials, foods (“Animal-Free Dairy”), fuels, and to upcycle waste