Louis pasteur and robert koch

Contribution of Louis Pasteur & Robert Koch in Medical Microbiology

1. Contribution of louis Pasteur and Robert Koch in medical microbiology

2. Louis pasteur Father of “Modern Microbiology” Trained chemist and microbiologist from France Developed the concept of fermentation Lactic acid fermentation is due to a microorganisms Yeasts are involved in alcoholic fermentation

3. His studies on fermentation of wine led him to take interest in microbiology. He is known as the founder or Father of Modern Microbiology. While studying fermentation of grapes in 1857, Pasteur noted that alcoholic fermentation of grapes, fruits and grains was caused by some microbial agents which were then called ferments by him. He further noted that different types of fermentations were brought about by different kinds of ferments-microorganism (1857). Pasteur applied the knowledge of his predecessors to his own research. He and his pupils devised basic principles and techniques of bacterial cultivation and laid down three principles. These are: 1. Every alternation of either wine or beer depends on development of microorganisms. 2. The microorganisms are brought by the ingredients or apparatus used in breweries. 3. Whenever beer or wine contains no living organisms, it remains unchanged.

4. Discovery of anaerobic life Proposed germ theory of disease Pasteur devised the process of destroying bacteria known as pasteurization. Pasteur in 1897 suggested that mild heating at 62.8˚C for 30 minutes rather than boiling was enough to destroy the undesirable organisms without ruining the test of the product, the process was called pasteurization. Development of methods and techniques of Bacteriology Studies on Pebrine (silk worm disease), Anthrax, Chickenpox, Cholera and hydrophobia Pasteur demonstrated disease of silkworm due to a protozoan parasite. He developed live attenuated vaccine for the disease. He demonstrated that the anthrax was caused by bacteria and also discovered vaccine for the disease.

5. Pasteur's brilliant and active research for a long period of 30 years (1860-1890) was acclaimed throughout the world. Some of his important contributions in microbiology are: Development of methods and techniques for cultivation of microorganisms. Conclusive evidence for microorganisms in disease production. Introduction of sterilization techniques and development of steam sterilizer, hot-air oven and autoclave. Tyndall (1877), a student of Pasteur, introduced the method of sterilization by repeated heating ( tyndallization ). Studies on pebrine (silk worm disease), anthrax, chicken cholera and hydrophobia. During studies on rabies, though Pasteur could not isolate any microorganism from man and dog, he reproduced the disease in healthy dogs in 1881 by intracerebral injection of saliva and brain tissue from an infective case. He suggested that the causative agent of rabies was too small to be seen by microscope.

6. Development of chicken cholera vaccine by pasteur

7. Discovered the theory of spontaneous generation. he pointed that no growth took place in swan neck shaped flask because dust and germs has been trapped on the walls of the curved neck but if the necks were broken off so that dust fall directly down into the flask, microbial growth commenced immediately.

8. Robert koch Robert Koch(1843-1910) was a german physician and microbiologist One of main Founder of modern bacteriology Introduced methods for isolation of pure culture He introduced gelatin as a setting agent in bacteriological media use of solid media for isolation of bacteria Staining techniques M odern medical microbiology began with Koch's systematic studies on anthrax in 1876 in Germany. 

9. Robert Koch laid the foundation of modern bacteriological technique- introducing glass slide and coverslip, examination by hanging drop, fixing and staining of bacteria, culture on solid media by pour plate method, disinfection by steam sterilization. Using these technique, he demonstrated streptococci and staphylococci as the common cause of wound disease. He identified specific causative agent of tuberculosis, cholera and anthrax and gave experimental support for the concept of infectious disease. discovered Anthrax bacillus (1876), Tubercle bacillus (1882) and cholera vibrios (1883) .

10. Koch’s postulates(1884) Microorganism can be accepted as the causative agent of an infectious disease only if following conditions are fulfilled: Disease agent must be present in every organism suffering from the disease but should be absent in healthy organism. It should be possible to isolate the microorganism in its pure culture from lesion of the disease The isolated microorganism when introduced into suitable laboratory animal should produce the similar disease It should be possible to re-isolate the microorganism in its pure culture from lesions produced in experimental animals.

11. Koch’s postulates