THE EARLY YEARS OF MICROBIOLOGY

Anton van Leewenhoek first to observe live microorganisms through the magnifying lenses of more than 400 microscopes he constructed

Is spontaneous generation (abiogenesis) of microbial life possible?

Francesco Redi set out in 1668 to demonstrate that maggots did not arise spontaneously from decaying meat.
Proved flies had to lay eggs for larvae to appear (2 experiments)

John Needham found that even after he heated nutrient fluids (chicken broth and corn broth) before pouring them into covered flasks, the cooled solutions were soon teeming with microorganisms.
Claimed that microbes developed spontaneously from fluids.

Lazzaro Spallanzani suggested that microorganisms from the air probably had entered Needham’s solution after they were boiled.
Showed that nutrient fluids heated after being sealed in a flask did not develop microbial growth

Rudolf Virchow challenged the case of spontaneous generation with the concept of biogenesis, the claim that living cells can arise only from preexisting living cells.

Louis Pasteur showed that microorganisms can be present in nonliving matter- on solid, in liquids, and in the air. (proved that spontaneous generation was false)
He demonstrated conclusively that microbial life can be destroyed by heat and that methods can be devised to block the access of airborne microorganisms to nutrient environments (aseptic techniques – techniques that prevent contamination by unwanted microorganisms )

1st vaccine – Edward Jenner :1796 – Small box – gave volunteer scraping of cowpox – never got small pox

Ignaz Semmelweis Demonstrated that the disease was transmitted by the hands and instruments of attending midwives or physicians that disinfecting the hands and instruments could prevent such transmission.

Recorded the number of births and maternal deaths at Vienna General Hospital.
Puerperal Sepsis (puerperal fever and childbirth fever) a nosocomial infection. Infection in uterus result of childbirth of abortion- to abdominal cavity then to sepsis. Caused by streptococcus pyogenes.

John Snow conducted a series of investigations related to outbreaks of cholera in London. He analyzed death records attributed to cholera, gathered information about the victims and interviewed survivors who lived in the neighborhood.
Concluded that contaminated water from the Broad Street pump was the source of the epidemic.

Epidemiology the study of when and where diseases occur and how they are transmitted in populations

THE GOLDEN AGE OF MICROBIOLOGY (1857-1914)

Fermentation Yeast convert the sugars to alcohol in the absence of air.

Pasteurs solution to the spoilage problem was toe heat the beer and wine just enough to kill most of the bacteria that caused the spoilage. This process is pasteurization – now commonly used to reduce spoilage and kill potentially harmful bacteria in milk as well as in some alcoholic drinks

The idea that microorganisms might cause disease is germ theory of disease.

Robert Koch found the first proof that bacteria actually cause disease. Discovered anthrax, a disease that was destroying cattle and sheep in Europe. Discovered rod-shaped bacteria now known as Bacillus anthracis.

Koch’s Postulates: the four steps that must be taken to prove the cause of an infectious disease

1. Microorganisms are isolated from a diseased or dead animal 2. A) The microorganisms are grown in pure culture
B) The microorganism are identified 3. The microorganism are injected into a healthy laboratory animal 4. The disease is reproduced in a laboratory animal; microorganism are isolated from this animal 5. A) The microorganisms are grown in pure culture
B) Identical microorganisms are identified

Joseph Lister’s Aseptic Surgery Applied the germ theory to medical procedures. Lister knew that phenol (carbolic acid) kills bacteria, so he began treating surgical wounds with a phenol solution. This practice reduced the incidence of infections and deaths that other surgeons quickly adopted it. This technique was one of the earliest medical attempts to control infections caused by microorganisms.

Florence Nightingale founder of modern nursing- Recorded statistics on epidemic typhus in the English civilian and military populations.
Published a thousand page report using statistical comparisons to demonstrate the diseases, poor food, and unsanitary conditions were killing the soldiers.

Paul Ehrlich’s Magic Bullets (Chemotherapy) this drug could “hunt down and destroy a pathogen without harming the infected host” This was the first shot in the chemotherapy revolution

In 1910 after testing hundreds of substances, he found a chemotherapeutic agent called salvarsan, an arsenic derivative effective against syphilis

Alexander Fleming: Antibiotics Looked for a mold that could inhibit the growth of a bacterium. The mold was later identified as Penicillium notatum ( Penicillin) – an antibiotic produced by a fungus

THE MODERN AGE OF MICROBIOLOGY

Recombinant DNA technology

Paul Berg showed that fragments of human or animal DNA (genes) that code for important proteins can be attached to bacterial DNA. The resulting hybrid was the first example of recombinant DNA
Recombinant DNA is inserted into bacteria it can be used to make large quantities of the desired protein. This technology that developed from this technique is called recombinant DNA technology