Microbiology

• Microbiology


  The study of small living things
• Medical Microbiology


  The study of causative agents of infectious diseases of humans and their reactions to such infections
• Aspects of medical microbiology

  • Etiology
  • Pathogenesis
  • Laboratory diagnosis
  • Specific treatments
  • Control of infections (immunizations)
• Pathogens


  Disease-causing microbes
• Non-pathogens


  Microbes that do not cause disease
• Indigenous microflora


  Microbes that live on and in our bodies
• Opportunistic pathogens


  Microbes that can cause disease, but usually do not
• Roles of microorganisms


  • Essential for life on this planet
  • Play essential roles in various elemental cycles
  • Used for bioremediation
  • Serve as food for tiny animals and important links in food chains
  • Aid in the digestion of food and produce beneficial substances
• Fossils of primitive microorganisms date back about 3.5 billion years ago
• Candidates for the first microorganisms on Earth are archaea and cyanobacteria
• Infectious diseases of humans and animals have existed for as long as humans and animals have inhabited the planet
• Microorganisms


  Single-celled organisms that cannot be seen by the naked eye, but can grow and form visible structures called colonies
• Microbes are found in many parts of the human body and in our surroundings
• Branches of microbiology


  • Agricultural microbiology
  • Food microbiology
  • Pharmaceutical microbiology
  • Industrial microbiology
  • Space microbiology
  • Medical Microbiology
• Disciplines within medical microbiology

  • General microbiology
  • Bacteriology (bacteria)
  • Virology (viruses)
  • Immunology
  • Mycology (fungi)
  • Parasitology (parasite)
• In the first ages, it was believed that diseases were caused by evil in the human soul as a punishment from God
• Religious men were the doctors in ancient civilizations
• The ancient Egyptian civilization (BC 3400-2450) started making sewage systems and mentioned the black death
• Hippocrates was the most outstanding figure in the history of medicine and the father of medicine
• Hippocrates described several infectious diseases and believed they were caused by bad air, water, stars, directionality of stars and seasons (miasma theory)
• Fracastorius proposed the idea of contagion and the germ theory of disease
• Antonie van Leeuwenhoek was the first man to see microorganisms and observe their shape and movements
• Louis Pasteur discovered that microorganisms are present in the air, and developed several vaccines including rabies and anthrax
• Robert Koch verified the germ theory of disease and developed methods to isolate and identify microorganisms
• Robert Hooke was the first to use a microscope to observe living things and coined the term "cell"
• Joseph Lister started using antiseptic solutions against wound and surgical infections, and is known as the father of antiseptics
• Charles Chamberland discovered the autoclave, a sterilizing tool used in laboratories and surgery rooms
• Varo, Columella, and Fracastorius proposed the idea of invisible beings (animalia minuta) as the cause of infectious diseases
• Hans and Zacharias Janssen created the first compound microscope in 1590
• Ferdinand Julius Cohn classified bacteria into four groups based on shape
• John Tyndall and Ferdinand Cohn discovered that some microorganisms are heat resistant
• Max Knoll and Ernst Ruska discovered the electron microscope in 1933, allowing visualization at the nanometer scale
• Alexander Fleming discovered penicillin in 1928, ushering in the era of antibiotics
• James Watson, Francis Crick, François Jacob, and Jacques Monod made major discoveries in genetics and molecular biology
• Baruch Bloomberg discovered the hepatitis B surface antigen (HBsAg) in 1965
• Classification of microorganisms by cell structure

  • Eukaryotes (humans, animals, etc. with true nucleus)
  • Prokaryotes (no nucleus, simple cell structure)
  • Viruses, virions, prions (energy parasites)
• Main groups of microorganisms

  • Eukaryotes: Algae, Fungi, Protozoa
  • Prokaryotes: Archaeabacteria, Cyanobacteria, Bacteria, Spirochetes, Chlamydia, Rickettsia, Mycoplasma
• According to Carl Woese, living organisms are divided into 3 domains: Bacteria, Archaea, Eukarya
• Microorganisms are involved in the decomposition of dead materials and waste products, and are used for bioremediation
• Microorganisms are involved in elemental cycles and serve as food for tiny animals in food chains