History of Microbiology

• Knowledge of tiny living things and their impact has only been around since the late 19th century

• Around the 1880s, it was still believed that life could form out of thin air and that sickness was caused by sins or bad odors

• Diseases were thought to be caused by bad smells, humor imbalance, and sins, and were treated by removing odors, bleeding, and prayer

• Varo and Columella in the first century BC believed that diseases were caused by invisible beings (Animalia minuta) inhaled or ingested

• Fracastorius of Verona (1546) proposed Contagium vivum as a possible cause of infection

• Von Plenciz (1762) suggested that each disease was caused by a separate agent

Discovery of Microbes and the Dawn of Microbiology

• Microbiology studies microscopic living organisms
• Louis Pasteur (1822-95) coined the term microbiology
• Microbiology science started with the expansion and development of the biological sciences after 1850
• Sedillot first used the term microbe (1878)

The Discovery Era

• Robert Hooke, in the 17th century, was the first to use a lens to observe cells
• Anton van Leeuwenhoek used homemade microscopes to observe "animalcules"
• Antonie van Leeuwenhoek (1632-1723) was the first to observe microorganisms (bacteria and protozoa), and accurately described them as 'animalcules' (1676)
• Leeuwenhoek was a linen merchant who built over 250 simple microscopes of double convex lenses held between two silver plates
• Those microscopes magnified around 50-300 times
• Leeuwenhoek was the first to produce precise and correct descriptions of bacteria and protozoa using a microscope he made himself
• Antonie van Leeuwenhoek is considered the "Father of microbiology" and also of bacteriology and protozoology (protistology)
• Leeuwenhoek wrote over 200 letters which were transmitted as a series of letters from 1674-1723 to the Royal Society in London

Transition Period

• After microorganisms were discovered, most scientists believed that life arose through spontaneous generation from mud, lakes, and other nutrient-rich sources

• Solving the controversy over spontaneous generation involved experiments mainly of Francesco Redi, John Needham, Lazzaro Spallanzani, Nicolas Appert, Ignaz Semmelweis, and John Snow

• Francesco Redi (1626-1697) challenged spontaneous generation by experimenting on decaying meat and its ability to spontaneously produce maggots

• John Needham (1713-1781) was a supporter of spontaneous generation, asserting that animalcules arose spontaneously on his mutton gravy

• Lazzaro Spallanzani (1729-1799) attempted to refute Needham's experiment by boiling beef broth for a longer period and sealing the flask, and thus disproved spontaneous generation

• Nicolas Appert followed Spallanzani's idea which shows that soups and liquids can be preserved by heating them extensively in thick champagne bottles

• Ignaz Semmelweis and John Snow showed a growing awareness of the mode of disease transmission.

• German scholars Schulze (1815-1873) and Theodor Schwan (1810-1882) viewed that air was the source of microbes and sought to prove this by passing air through hot glass tubes or strong chemicals into boiled infusions in flasks

• George Schroeder and Theodor Von Dusch (1854) first used cotton plugs for plugging microbial culture tubes

• Darwin (1859) showed that the human body could be conceived as a creature susceptible to the laws of nature

The Golden Age

• The Golden Age of microbiology began with the work of Louis Pasteur and Robert Koch

• The concept of spontaneous generation was put to rest by Louis Pasteur via experiments involving a goosenecked flask

• By showing that he could allow air to get into the flask but not the particles in the air, Pasteur proved that it was the organisms in the dust that were growing in the broth

• Pasteur resolved the spontaneous generation versus biogenesis controversy in 1858

• Fermentation of fruits and grains, resulting in alcohol, was brought about by microbes

• Bacteria were responsible for the spoilage of wine during fermentation

• Pasteur suggested in 1862 that mild heating at 62.8°C (145°F) for 30 minutes, rather than boiling, was enough to pasteurize, and this was introduced into the United States on a commercial basis in 1892

• Pasteur work led to developing germ theory

• Louis Pasteur is known as the "Father of Modern Microbiology/ Father of Bacteriology"

• John Tyndall (1820-1893) dealt a final blow to spontaneous generation in 1877

• Tyndall's experiment showed that with no dust, sterile broth remained free of microbial growth

• Tyndall discovered highly resistant endospores in the infusion

• Prolonged boiling or intermittent heating was necessary to kill these spores: tyndallisation

• Robert Koch sought the causes of nasty animal diseases(anthrax and tuberculosis)

• Koch first demonstration of the role of bacteria in causing disease

• Koch who first isolated Bacillus anthracis (the cause of anthrax) in 1876

• Koch perfected the technique of isolating bacteria in pure culture and introduced the use of solid culture media in 1881 by using gelatin as a solidifying agent

• Koch discovered Mycobacterium tuberculosis in 1882 and proposed Koch postulates

• Koch postulates are used today to prove the etiology of an infectious disease Koch's postulates include that the organism -

  • causing the disease can be found in sick individuals but not in healthy ones
  • can be isolated and grown in pure culture
  • must cause the disease when introduced into a healthy animal
  • must be recovered from the infected animal

• Combined efforts of Louis Pasteur, Robert Koch, and others led to the Germ theory of disease

• The idea that invisible microorganisms causes disease

• Fanne Eilshemius Hesse (1850 - 1934) proposed using agar in culture media to create a superior solidifying agent

• Richard Petri developed the Petri dish (plate), a container used for solid culture media in 1887

• The work of Robert Koch, Fannie Hesse, and Richard Petri made possible the isolation of pure cultures

Development of Vaccines

• Initial surgery was as dangerous as doing nothing at all, but once scientists realized microbes caused disease, aseptic (sterile) technique was introduced

• Lord Joseph Lister (1827-1912) created a system of antiseptic surgery to prevent microorganisms in wounds by the application of phenol to surgical dressings (1867)

• Joseph Lister used a fine mist of carbolic acid and is known as the Father of Antiseptic surgery

• Hand washing and quarantining patients reduced the spread of disease

• Vaccination was discovered before germ theory, but was not understood until time of Pasteur

• Edward Jenner used pus from cowpox scabs to vaccinate people against smallpox in the late 18th century

• Edward Jenner (1749-1823) was the first to prevent small pox by inoculating people with pus from cowpox lesions (May 14th,1796)

• Jenner results were published on 23 successful vaccinators in 1798 and the process was named 'Vaccination'

• The use of cow pox virus to protect small pox became popular

• Jenner's vaccination of smallpox caused the principal of the preventive treatment of rabies to work

• Pasteur applied this principle to prevent anthrax and it worked resulting in attenuated cultures vaccines (Vacca = cow)

• The process of the vaccination and the preventive treatment of rabies laid the foundation of modern immunization programme to against dreaded diseases

• Elie Metchnikoff (1845-1916) proposed the phagocytic theory of immunity in 1883 via blood cells known as phagocytes

Development of Chemotherapeutics, Antitoxins and Antibiotics

• Emile Roux (1853-1933) and Alexandre Yersin demonstrated toxin production in filtrates of broth cultures of the diphtheria organism
• Emil von Behring (1854 -1917) and Shibasaburo Kitasato (1852-1931) discovered tetanus (lock jaw) antitoxin in 1890
• Von Behring also immunization against infection
• Paul Ehrlich (1854-1915) found that the dye Trypan Red had antimicrobial activity against sleeping sickness used it therapeutically as a 'magic bullet'.
• Ehrlich and Sakahiro Hata introduced the arsenical drug Salvarsan to treat syphilis via chemotheropy
• Gerhard Domagk of Germany (1935) used Prontosil, a red dye, and discovered that was active against Streptococci and Staphylococci
• Jacques and Therese Trefonel showed that the compound Prontosil was broken down within the animal to sulfanilamide (Sulfa drug)
• Domagk was awarded nobel prize in 1939 for the discovery of the first sulpha drug
• Sir Alexander Fleming discovered penicillin in 1929 via mold in test tube while trying searching something that woud kill wound infections from war
• Penicillin used to treat people suffering from a variety of bacterial infections in burn victims
• Waksman at the Rutgers university, USA discovered another antibiotic (1944)
  • Streptomycin produced by two strains of actinomycete, Streptomyces griseus
• Waksman received noble prize in 1952 for Streptomycin used in tuberculosis
  • tuberculosis (bacterial disease caused by Mycobacterium tuberculosis by Robert Koch in 1882)
  • additional antibiotics include chloramphenicol (Chloromycetin), Aureomycin, and Terramycin
• After the death of Robert Koch (1910) during World War 1, microbiology research declined and The Pasteur Institute and German laboratories were closed

In 20th Century: Era of Molecular Biology

• By the end of 1900, microbiology grew to adolescence stage and later led to microbiology and molecular biology
• Microorganism became tools to study life processes -relative simplicity, short life span, and genetic homogeneity provided an authentic simulated model to life processes
  • Molecular biology made great studies by using bacteria and to learning genetic code, how DNA is regulated, and how RNA is translated

Important Contributors in Microbiology

• Louis Pasteur : Father of Modern Microbiology / Bacteriology
  • proposed the principles of fermentation for preservation of food
  • sterilization techniques, steam sterilizers, hot air oven, and autoclave
  • pasteurization of milk
  • vaccine designs to treat anthrax, fowl cholera, and rabies
  • disproved the theory of spontaneous generation of disease and germ theory of disease
  • liquid media concept and nutrient broth to grow microorganisms
• Robert Koch:
  • solid media for the culture of bacteria suggested the use of agar
  • methods for isolation of bacteria in pure culture
  • hanging drop method for testing motility
  • anthrax bacilli, tubercle bacilli, and cholera bacilli
  • Introduced staining techniques by aniline dye
• Koch Phenomenon: Robert Koch observed that guinea pigs infected with tubercle bacillus showed a hypersensitivity reaction when injected with its protein
• Koch's postulates, is a microorganism is accepted with infectious disease: - microorganism should be associated with lesions of the disease - isolate to be pure from lesions of the disease - disease must occur from inserting into animal - re isolate the organism in pure culture from the lesions produced in the experimental animals
• Paul Ehrlich- - acid-fast nature of tubercle bacillus report - techniques to stain tissues and blood cells developed - toxin-antitoxin interaction called an - Ehrlich phenomenon for standard toxin and antitoxin - side-chain antibody production thepry - Discovered Salvarsan magic bullet treatment of syphilis and the father of chemotherapy
• Other important figures:
  • Antonie Philips/ Phillip van Leeuwenhoek discovered the single lens microscope and named organisms as 'Little animalcules' - Edward Jenner developed first vaccine on cowpox against smallpox - Joseph Lister: Father in Surgery in antiseptic surgeries due to carbolic acid - Hans Christian Gram: Developed to 'Gram stain' -Ernst Ruska founder the electron microscope. - Alexander Fleming discovered bacteria penicillin. -Elie Metchnikoff described phagocytosis and phagocytes term - Kleinberger, Barbara McClintock, Walter Gilbert, Frederick Sanger, Karry B Mullis contributed also

Explore the pivotal experiments that shaped microbiology, including Pasteur's gooseneck flask experiment disproving spontaneous generation. Learn about the aseptic techniques introduced by Schroeder and Von Dusch, along with Koch's postulates and the impact of hand washing.