MEDICAL MICROBIOLOGY

What is microbiology? Microbiology is the study of microorganisms. Microorganisms are organisms, or agents, too small to be seen clearly by the unaided eye. Bacteria, protists, viruses, fungi, molds, etc.

4 Categories of Microbes ARCHAE BACTERIA EUKARYOTES VIRUSES 4 Categories of Microbes All of these categories are based on the types of cells in each kind of organism.

TRUE OR FALSE? All bacteria are harmful. All viruses are harmful. All protists are harmful. FALSE All fungi are harmful. FALSE All microbes are pathogenic. FALSE

HISTORY OF MICROBIOLOGY: The Beginnings What are some things that you know about microorganisms? What did people in ancient times think made diseases, etc., happen? Why? When did people begin to understand that microbes were responsible? Microbes were the first organisms to inhabit Earth. Why were they some of the last organisms to be identified?

What important invention made it possible to see microorganisms? The Microscope Made the invisible world visible. Probably first made by Zacharias and Hans Janssen, Danish lens makers. Galileo Galilei also made some. Popularized when Anton von Leeuwenhoek drew pictures of microbes with his microscope.

Leeuwenhoek’s microscope

Leeuwenhoek (lived 1632-1723) called the small microbes “animalcules.”

Robert Hooke Please read the article on Robert Hooke, found at the website given here: http://www.history-of-the-microscope.org/robert-hooke-microscope-history-micrographia.php For extra credit, write a summary of this article. Be sure to include several of the contributions made by Hooke in the research of other scientists. Explain why he has often been overlooked in areas other than biology.

Using the above microscope, Hooke investigated a large number of living things, including the thinly sliced cork that is pictured to the left. This is a duplicate of his drawings. He thought that the empty spaces, somewhat in the shape of rectangles, looked like the small rooms that monks lived in. Those rooms were called CELLS.

THE CELL THEORY The three tenets (parts) to the cell theory are described as follows: All living organisms are composed of one or more cells. (However, this is controversial because non-cellular life such as viruses are disputed as a life form. The cell is the basic unit of structure and organization in organisms. Cells arise from pre-existing cells. Theodor Schwann and Matthias Jakob Schleiden; Rudolf Virchow.

HISTORY OF MICROBIOLOGY:Transition Period ARISTOTLE: (384 – 322 BC) Ancient Greek philosopher. Considered to be an expert of art, science, math, and philosophy. He believed that living things could come from nonliving things. A “vital force” caused this phenomenon to occur. This idea/hypothesis is called spontaneous generation. However, Aristotle never carried out a scientific experiment to test his ideas. The Great Debate over Spontaneous Generation

Spontaneous Generation was not completely disproven until 1800’s. Francesco Redi performs an experiment that “disproves” spontaneous generation. John Needham and Lazzaro Spallanzani carry out “rival” experiments. Louis Pasteur finally proves that spontaneous generation could not produce new microorganisms.

HISTORY OF MICROBIOLOGY: The Golden Age LOUIS PASTEUR (French; 1822 – 1895) Disproved spontaneous generation Saved the French wine industry by disovering when bacteria entered the fruit juices, a type of vinegar was produced instead of wine (that resulted from yeast). Developed the process of pasteurization to kill the bacteria in wine, beer, and milk. HISTORY OF MICROBIOLOGY: The Golden Age 1857 – 1914 Pasteur Semmelweiss Lister Koch

More about Pasteur Saved the silk industry by identify bacteria that destroyed the cocoons and developed a way to kill the bacteria without destroying silk. Developed vaccines for cholera, antrax, rabies and smallpox.

Ignaz Semmelweiss Ignaz Philipp Semmelweis (1818-65), a Hungarian obstetrician, introduced antiseptic prophylaxis into medicine. In the 1840s, puerperal or childbirth fever, a bacterial infection of the female genital tract after childbirth, was taking the lives of up to 30% of women who gave birth in hospitals. Women who gave birth at home remained relatively unaffected. He instructed doctors to wash their hands with chlorinated lime before examining the women.

JOSEPH LISTER The Father of Antiseptic Surgery Lister moved to Glasgow in 1860 and became a Professor of Surgery. He read Pasteur's work on micro-organisms and decided to use Pasteur’s idea of exposing a wound to chemicals during surgery. He chose  carbolic acid (phenol) to cover the wound and the rate of infection was vastly reduced. Lister then experimented with hand-washing, sterilizing instruments and spraying carbolic in the theatre while operating, in order to limit infection. His lowered infection rate was very good and Listerian principles were adopted throughout many countries by a number of surgeons. Born in England in 1827. Physician, surgeon, and scientist.

ROBERT KOCH and the Germ Theory of Disease Koch’s 4 Postulates The causative agent must be present in every individual with the disease. The causative agent must be isolated and grown in pure cultures. The pure culture must cause the disease when inoculated into an experimental animal. The causative agent must be reisolated from the experimental animal and reidentified in a pure culture. The main idea of the germ theory is that specific diseases are caused by specific germs. Many of his conclusions were made during experimentation of anthrax, a bacterial disease which affects animals.

HISTORY OF MICROBIOLOGY 1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis 1930’s: Synthesis of sulfonamides 1928: Alexander Fleming and the discovery of the first antibiotic The Birth of Modern Chemotherapy

Modern Developments in Microbiology Bacteriology – Mycology – Parasitology – Virology – Immunology Microbial genetics and molecular biology lead to Recombinant DNA Technology (genetic engineering).