Lecture Notes: The Birth of Microbiology and Chemotherapy

Introduction

• Microorganisms caused the most devastating diseases in history.
• Humans were unaware of their existence for over 99% of history.
• Solutions were found through trial and error without understanding disease etiology.

Early Speculation and Discovery

• Speculation existed about tiny living beings.
• Antonie van Leeuwenhoek (1674):
  • Built a simple microscope.
  • Described "animalcules" (bacteria, protozoa, fungi).
• Birth of microbiology went largely unnoticed until two centuries later.

Development of Microbiology

Fermentation and Spoilage

• Scientists debated causes of fermentation:
  • Spontaneous processes?
  • Invisible organisms multiplying from air?
  • Correct theory: Microorganisms in the air settle on nutrients and multiply.

Louis Pasteur

• Recognized as the father of microbiology.
• Conducted experiments with swan-necked flasks:
  • Airborne microorganisms cause fermentation.
  • Introduced pasteurization (rapid heating and cooling to prevent spoilage).
• Postulated germ theory of disease after personal losses to illness.

Joseph Lister

• Developed sterile surgery techniques inspired by Pasteur's theories.
• Used carbolic acid as an antiseptic.
• Reduced post-operative infections significantly but faced initial skepticism.
• Recognized as the father of modern surgery, contributing to surgical hygiene practices.

Pasteur's Later Contributions

• Focused on immunization:
  • Proposed using weakened microorganisms for vaccinations.
• Coined the term "vaccines" in honor of Edward Jenner.
• Remembered for his significant contributions to microbiology and immunology.

Robert Koch

• Co-founder of microbiology; developed Koch's postulates:
  1. Isolate the microorganism from a sick individual.
  2. Grow it in lab culture.
  3. Inject it into a healthy individual to observe disease development.
  4. Re-isolate the microorganism from the newly sick individual.
• Worked on tuberculosis: Isolated Mycobacterium tuberculosis, proving it caused the disease.
• Received the Nobel Prize (1905) and established the Robert Koch Institute.

Legacy of Pasteur and Koch

• Marked a transition from ignorance to understanding of disease etiology.
• Laid foundations for modern microbiology and immunology.

Development of Chemotherapy

Paul Ehrlich

• Considered the father of chemotherapy.
• Focused on treating syphilis with compound 606 (Arsphenamine, Salvarsan).
• Faced controversy regarding toxicity and moral implications of his work.
• Proposed the "magic bullet" concept for targeted drug delivery.

Conclusion

• Major advancements in understanding microorganisms and treatment efficacy.
• Set the stage for modern pharmaceutical practices and ongoing research in treating infectious diseases.