Microbiology: The study of microscopic organisms that cannot be seen by the naked eye.

Microorganisms / Microscopic Organisms: Living organisms which can only be seen with the aid of a microscope.

The microorganisms of medical importance are four, namely:

• Bacteria
  Viruses
  Fungi
  Protozoa

HISTORY OF MICROBIOLOGY

Some of the outstanding individuals who contributed to modern microbiology include:

ANTON VAN LEEUWENHOEK (1632-1723)
He was a Dutch scientist, commonly known as the “Father of Microbiology,” and one of the first microscopists in history.
He committed himself to discovery and research related to the invisible world of biology; notable among his achievements is the discovery of protozoa (e.g., Giardia lamblia) and being the first to describe red blood cells.

EDWARD JENNER (1749-1823)
As a youth, he discovered that people who contracted the relatively harmless cowpox disease could not contract smallpox. In 1796, he inoculated a young boy with exudates taken from fresh cowpox lesions of a dairymaid.
The boy contracted cowpox and, when subsequently inoculated with smallpox, did not contract the deadlier disease. This procedure spread, and the death rate from smallpox fell (reduced).

LOUIS PASTEUR (1822-1895)
Discovered that microbes were responsible for souring alcohol and developed the process of pasteurization, where bacteria were destroyed by heating beverages and then allowing them to cool.
His work on the germ theory also led him and his team to create vaccinations for anthrax and rabies.

JOSEPH LISTER (1827-1912)
He observed that 45-50% of amputated patients died from sepsis. In 1865, he learned of Louis Pasteur’s theory that microorganisms cause infections. Using phenol, he reduced the mortality rate in his ward by 15% within 4 years. Today, he is regarded as the founder of antiseptic medicine.

ROBERT KOCH (1843-1910)
Was a physician best known for isolating the tuberculosis (T.B.) bacterium, which was the cause of numerous deaths in the mid-19th century, and won the Nobel Prize in 1905 for his work.
He is considered one of the founders of microbiology and developed criteria, which he named Koch’s Postulates, meant to establish a causal relationship between a microbe and a disease.

ALEXANDER FLEMING (1881-1955)
Served as a physician during World War I. Through research and experimentation, he discovered a bacteria-destroying mold, which he called “penicillin,” in 1928, paving the way for the use of antibiotics in modern healthcare.

Important Terminologies

REPLICATION: Refers to the multiplication/reproduction of microorganisms.
PATHOGEN: Refers to microorganisms capable of causing disease.
MORPHOLOGY: Refers to the structure or shape of microorganisms.
PATHOGENICITY: Refers to the ability of microorganisms to cause disease.
MICROBE: Refers to a minute microorganism which can only be seen with the help of a microscope under high power of magnification.
HOST: Any organism on which another living organism lives as a parasite.
PARASITE: Any organism which lives at the surface or in the tissues of another living organism called a host.

Why Study Microbiology in Nursing?

• To understand diseases caused by microorganisms.
  To gain insight on how microorganisms cause diseases in the human body.
  To understand the modalities of controlling infections.
  To gain insight on how to treat infections.

IMPORTANCE OF MICROORGANISMS

• For decomposition of waste materials.
  Fermentation during brewing.
  Protect against diseases.
  Manufacture of drugs.
  Provision of body nutrients like Vitamin K from E. coli.
  Help in fixing nitrogen into the soil.
  Study purposes.
  They cause infections.