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Introduction to Microbiology



Microbiology is the study of organisms too small to be seen without magnification, called microorganisms or microbes. Microbes can include bacteria, unicellular fungi, protozoa, and helminths. Microbes also include viruses, which are not considered to be alive because they are not composed of cells. Microbiology consists of several major areas of focus. Immunology is the study of infectious diseases and immunity. Bioremediation is the utilization of microbes to break down pollution. Food microbiology is the study of microbes that live or produce human food. Aquatic microbiology is the study of microbes in water. The “Golden Age of Microbiology” was a time between 1850 and 1930 when the foundational discoveries in the field of microbiology were made. Discoveries by Louis Pasteur and Joseph Lister laid the foundation for the germ theory of disease, which states that microbes cause diseases. Robert Koch laid out four rules (Koch's postulates) providing a scientific framework for positively identifying the microbe responsible for a disease. Alexander Fleming was the first to discover antibiotics.

At A Glance

  • Microbiology is the study of microbes, organisms too small to be seen without magnification, including bacteria, viruses, unicellular fungi, protozoa, and helminths.
  • Microbiologists may focus their study on a particular group of microorganisms, a habitat where they live, a specific type of disease they cause, or a specific application associated with their growth.
  • In the study of microbiology, the most common groups of microbes studied are bacteria, viruses, fungi, protozoa, and helminths.
  • The Golden Age of Microbiology was a time of tremendous advancement during the mid-19th through early 20th centuries with the discovery of the role microbes play in disease and identification of many pathogens.
  • The germ theory of disease, introduced by Louis Pasteur in the mid-19th century, states that infectious diseases are caused by microbes.
  • German microbiologist Robert Koch developed four rules, or postulates, that conclusively identify the bacterium that causes a particular disease.
  • Major developments in microbiology in the 20th century included the discovery of penicillin, the isolation and analysis of viruses, and the use of microbes to generate fuel sources.