Introduction to Microbiology

Microbiology What is Microbiology? Microbiology -The science of microorganisms (very small, unicellular organisms).Usually requires a magnification tool – the microscope. Microorganisms or microbes- these microscopic organisms Commonly called “germs, viruses, agents…” but not all cause disease and many more are useful or essential for human life Some organisms are large though – Helminths – worms Sub groups of Microbes we will study Bacteria Archaea Fungi Protozoans Algae Viruses Multicellular animal parasites – Helminths

Bacteria

Fungi

Protozoans Giardia Ameba

Viruses Bacteriophage Avian Flu

Helminth Tapeworm

Why Do We Study Microorganisms? We study microbiology because bacteria, viruses and fungi are the leading cause of death in the history of mankind. Some Microorganisms Benefit Man: - Many microorganisms are involved in the production of food or are directly edible. - The presence of bacteria (normal flora) in our bodies inhibits the growth of potentially pathogenic bacteria helping to keep us healthy..

Why Do We Study Microorganisms? Some Microorganisms Benefit Man: - Modern biotechnology is often associated with the use of genetically altered microorganisms such as E. coli or yeast for the production of substances like synthetic insulin or antibiotics. - Biotechnological advances in agriculture also require the help of microorganisms to form Transgenic Plant with increased yield, reduced vulnerability to environmental and pathogenic stresses, and improved taste.

Why Do We Study Microorganisms? Some Microorganisms Benefit Man: - Microbes are involved in cycling vital elements such as carbon and nitrogen, breaking down wastes and dead organisms into simpler substances plants can use in photosynthesis. Other species are at the base of the food chain, especially in aquatic ecosystems. Even pathogens have a role in controlling the populations of their host species. Microbes are even used to digest oil from oil spills.

Brief History of Microbiology The Microscope Fermentation and Pasteurization Germ Theory The Birth of Modern Chemotherapy Antiseptics and Hand Washing

The First Microscope Microbes were first observed by Antonie van Leeuwenhoek using a simple microscope (ca. 1676) Reported his “animalcules” to the Royal Society of London

History 1676 –first observation of bacteria “animalcules” Anton Von Leeuwenhoek

Antoni van Leeuwenhoek Inventor of the first microscope (1675)

The Golden Age of Microbiology 1857-1914 Beginning with Pasteur’s work, discoveries included the relationship between microbes , Fermentation and Pasteurization

Fermentation and Pasteurization Pasteur showed that microbes are responsible for fermentation. Fermentation is the conversation of sugar to alcohol to make beer and wine. Microbial growth is also responsible for spoilage of food. Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar (acetic acid).

Fermentation and Pasteurization Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. This application of a high heat for a short time is called pasteurization. Figure 1.4

Louis Pasteur Showed microbes caused fermentation Studied spoilage and introduced “Pasteurization” to prevent it Used cotton plugs in his cultures to prevent air borne contamination, devised Aseptic Technique.

History Louis Pasteur

Louis Pasteur put an end to Abiogenesis debate with his Goose Neck Flask Experiment He is the father of Microbiology

Germ Theory of Disease Proof that microorganisms caused disease Robert Koch demonstrated that anthrax was caused by Bacillus anthracis Blood from a diseased animal caused disease in a healthy animal Cultivated the disease causing agent outside the animal’s body, then introduced the agent into a healthy animal which subsequently developed the disease

Germ Theory of Disease 1876 - Robert Koch provided proof that a bacterium causes anthrax using experimental steps now called the Koch’s Postulates He was the first to use agar as solid culture medium in bacteriology.

Koch’s Postulates The microbe must always be present in every case of the disease It must be isolated in pure culture on artificial media When inoculated into healthy animal host it should produce the same disease It must be isolated from the diseased animal again

History 1884 Koch’s Postulates of Disease Transmission Robert Koch

The Birth of Modern Chemotherapy Treatment with chemicals is chemotherapy. Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics. Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes. Quinine from tree bark was long used to treat malaria. 1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis. 1930s: Sulfonamides were synthesized.

The Birth of Modern Chemotherapy 1928: Alexander Fleming discovered the first antibiotic. He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus. 1940s: Penicillin was tested clinically and mass produced. Similar to Figure 1.5

History 1929 Discovery of Penicillin (first antibiotic) Alexander Fleming

Antiseptics and Hand Washing 1860s -Joseph Lister used, carbolic acid, a chemical antiseptic to prevent surgical wound infections Ignaz Semmelweis, a Hungarian physician introduced hand washing as a means of preventing transfer of puerpueral sepsis in obstetrical patients

Lister Antisepsis in surgery

History 1867 Antiseptic Surgery Joseph Lister

Semmelweis

History 1938 – First Electron Microscope The electron microscope is capable of magnifying biological specimens up to one million times. These computer enhanced images of 1. smallpox, 2. herpes simplex, and 3. mumps are magnified, respectively, 150,000, 150,000 and 90,000 times.

History 1885 - Vaccine against Rabies Louis Pasteur

History 1796 – First vaccine (smallpox) Edward Jenner

History 1954 Polio Vaccine Jonas Salk