Microbiology

Concept of Microbiology

Microbiology is the branch of biology that studies the organisms of microscopic dimensions – micro-organisms – and includes Virology, bacteriology, Phycology (or Algology), Mycology, and Protozoology.

The existence of living entities invisible to the human eye was suspected since antiquity. However, this confirmation only happened in 1674, when Antoni van Leeuwenhoek, a Dutch cloth merchant, created the first microscope. With this equipment, van Leeuvenhoek visualised a huge diversity of microscopic organisms, movable or immovable “animalcules” with various shapes, in water and saliva samples, among others. However, the role of microorganisms in human and animal diseases was only identified later in the 19th century, through the experiments of Robert Koch and Louis Pasteur.

Some of the main events and discoveries in the field of Microbiology:

1674 – Antoni van Leeuwenhoek creates the first microscope;

1796 – Edward Jenner develops the first vaccine: the smallpox vaccine;

1850 – Pierre Rayer and Davaine Casimir discover the causative agent of carbuncle (anthrax);

1857-1858 – Louis Pasteur studies the fermentation (lactic and alcoholic);

1867 – Joseph Lister performs the first aseptic surgery;

1875 – Robert Koch develops techniques for fixing and staining bacteria;

1877 – Charles Chamberland, collaborator of Louis Pasteur, develops the method of sterilization by moist heat under pressure (autoclaving); John Tyndall develops the sterilization process that will be later called tyndallization;

1880 – Alphonse Laveran discovers Plasmodium sp., the parasite responsible for malaria;

1881 – Louis Pasteur develops a vaccine against carbuncle; Robert Koch develops methods of isolation of microorganisms in solid media;

1882 – Robert Koch identifies the bacteria, Mycobacterium tuberculosis, responsible for causing tuberculosis; Walther and Fanny Hesse develop a culture medium with agar;

1883 – Robert Koch identifies the bacteria, Vibrio cholerae, responsible for causing cholera;

1884 – Louis Pasteur develops a vaccine against rabies; Hans Gram develops the method of differential staining of bacteria known as Gram staining; Robert Koch formulates Koch’s postulates;

1885 – Theodor Escherich identifies the bacteria Escherichia coli;

1887 – Julius Petri creates the Petri dish;

1894 – Alexandre Yersin and Kitasato Shibasaburō identify the bacteria Yersinia pestis responsible for the black plague;

1898 – Martinus Beijerinck discovers viruses;

1920 – Albert Calmette and Camille Guérin develop the tuberculosis vaccine – Bacillus Calmette-Guérin or BCG;

1929 – Alexander Fleming discovers penicillin;

1944 – Albert Schatz and Selman Waksman discover streptomycin;

1969 – Thomas Brock discovers the thermo-resistant bacteria Thermus aquaticus, in Yellowstone National Park;

1980 – The World Health Organization declares smallpox eradicated;

1981 – The recombinant hepatitis B vaccine is available for the first time;

1983 – Luc Montagnier and Robert Gallo isolate and identify the HIV virus;

1984 – The HIV genome is sequenced;

1988 – The DNA polymerase from T. aquaticus is used in the DNA amplification technique: the polymerase chain reaction (PCR);

1997 – The largest bacterium ever described is discovered: Thiomargarita namibiensis.

References:

• Dedet, J. P. (2007). La microbiologie, de ses origines aux maladies émergentes. Paris: Dunod.
• Fonseca, A. F. (1998). História da Microbiologia. In: Ferreira, W. F. and Sousa, J. C. Microbiologia – Volume 1. Lisboa: Lidel. P1-11.
• Prescott, L. M. et al. (2010). Microbiologie. 3rd ed. Bruxelles: de Boeck. p1-17.