BABCOCK UNIVERSITY COURSE CODE: MLSC 201 LECTURE TOPIC: HISTORY AND EVOLUTION OF MICROBIOLOGY

1. BABCOCK UNIVERSITY COURSE CODE: MLSC 201 LECTURE TOPIC: HISTORY AND EVOLUTION OF MICROBIOLOGY

2. Lecture Objectives • At the end of the lecture, the student should be able to: • Define medical microbiology • Name 4 pioneers of science of microbiology • List the landmark discoveries in the evolution of microbiology

3. WHAT IS MICROBIOLOGY? • The study of microorganisms and their activities: Nutrition, multiplication, pathogenicity, control, etc. • WHAT ARE MICROORGANISMS? • They are very minute organisms that are too small to be seen with the naked eye. They are also referred to as microbes. • They are observed with the of a magnifying device called the microscope.

4. WHAT IS MEDICAL MICROBIOLOGY • The study of disease causing microorganisms with respect to man. • Disease caused by a microorganism is called “infectious disease” or simply, “infection”. • Differentiate disease from infection!! • The more we know of microorganisms, the more the quality of human life is improved.

5. EVOLUTION AND HISTORY OF MICROBIOLOGY • The science and evolution of microbiology is an interesting chronicle of man’s indomitable spirit to conquer. • The history is loaded with landmark breakthroughs of early scientists that has made microbiology as one of the most applied sciences.

6. Brief History • Prior to the discovery of microorganisms, there were two kingdoms of living things: Plant and animal. • 1675: Anthony van Leeuwoenhoek, a Dutch draper, described the “little animals” (animacules) he observed with his crude home made microscope while examining rain water and watery infusions. • He was the first man to describe microorganisms.

7. Controversy similar to one concerning the origin of life was witnessed in the case of the origin of microorganisms. • The theory or concept of “spontaneous generation” was put forward and believed by many scientists for centuries. • They believed that life arose spontaneously from pre-existing life and so the term “abiogenesis”.

8. Meanwhile, there were opponents of this idea. The controversy was on for over 100 years. • In 1868, an Italian scientist, Francesco Redi, after many smart experiments, disproved the theory of abiogenesis. • Louis Pasteur (1822-1895), a French chemist ( the father of modern medicine), performed series of brilliant researches and experiments for the wine industry between1860 and1890.

9. Through his several experiments in the wine industry, was able to debunk the spontaneous generation hypothesis. He described vaccine and vaccination to protect against microbial activity. • He developed methods of culture and showed that microorganisms cause disease. With other scientists, he formulated the “germ theory of disease”. • He established the principles of immunisation. • He collaborated with John Tyndall (1820-1883) a physicist, to convince others about fallacy of abiogenesis and proof of biogenesis.

10. Joseph Lister, Professor of surgery in Glasgow, applied Pasteur’s observations to the prevention of wound sepsis. • In 1867, he discovered the use antiseptic technique to kill bacteria in wound and air with carbolic acid. • Robert Koch (1843-1910) (father of medical microbiology), a German scientist, discovered that bacteria caused diseases such as tuberculosis, anthrax etc.

11. Most of his work was between 1876 and 1884. He discovered the anthrax bacillus in 1876 ahead of Pasteur and two of them had become rivals. • With his assistant, Ehrlich (who worked on dyes), they were able to stain bacteria and viewed them on the microscope. • He introduced agar as gelling agent for culture media. He was the pioneer in laboratory technique. • He enunciated the famous Koch’s postulates:

12. 1. The organism must be found in every case of the disease. • 2. The organism must not be found in a healthy person. • 3. The organism must be isolated and grown in pure culture. • 4. Inoculation into a susceptible animal should reproduce the disease and the organism isolated from the animal. • 5. Infection should produce circulating antibody specific for the infecting organism.

13. It is obvious now with current knowledge that all the postulates are not applicable in every disease condition. • CONFUSION: • In-spite of the tremendous progress made, there was still confusion. • Living things then belonged to Animal kingdom or Plant kingdom • In which kingdom did these microorganisms belong?

14. 1866: Hackelproposed the creation of a third kingdom – the Protista • Protista included: algae, protozoa, fungi, bacteria and viruses. • 1957: Stanierdivided Protista into Eukaryotic (higher) cells and Prokaryotic (lower) cells. • To minimise the confusion, microbiology was broken into Bacteriology, Virology, Parasitology and Mycology.