History of microbiology-----------------------

History of microbiology is divided in to three stages namely Discovery stage, Transition stage and Modern microbiology. 

Discovery Stage:

1. Aristotle (384-322) described living and non-living organisms and their differentiation.

2.  Roger Bacon (13th Century) described that diseases are caused by living creatures.

3. Thereafter in 1546, Fracastorius described that communicable diseases were caused by living agents known as germs. 

4. In 1665, the first report on cell structure was described by Robert Hooke. 

5. Later, during mid of 1600’s, Antony van Leeuwenhoek (1632-1723) was the first person who used a microscope of his own design to direct observations of microbes. He discovered microorganisms in 1675 and named bacteria and protozoa as “Animalcules”. He has provided full description of bacteria. From that time he was known as one of the founders of microbiology.

6. In 1659, Kircher was reported minute worms in the blood during plague attack to human.

Transition stage:

1. In this era, Francesco Redi (1626-1697) showed that maggots would not arise from decaying covered meat. 

2. Further John Needham (1713-1781) proposed that tiny organisms arise spontaneously on the mutton gravy and he supported the spontaneous generation theory. 

3. There after Lazzaro Spallanzani (1729-1799) demonstrated that air carried germs to  the culture medium and also revealed that boiled broth would not give growth of microorganisms. 

4. In Next, John Tyndall (1820-1893) in 1877 proved the need for prolonged heating for elimination of microbial life from infusions, which are recently termed as tyndallization in which heat stable as well as heat sensitive bacteria both are killed. 

5. In 1835, Augustino Bassi demonstrated that a silk worm disease called muscardine was due to fungal infection.

Modern microbiology:

The actual development of microbiology came with Louis Pasteur, Robert Koch, Lord Lister, Alexander Flemming and Paul Ehrlich. 

☝Louis Pasteur 

1. Louis Pasteur is known as the father of medical microbiology because he has coined the terms microbiology, aerobic and anaerobic. 

2. In 1897, he suggested that mild heating at 62.8°C for 30 minutes was more effective than boiling to destroy the pathogenic organisms without change of taste of the product. This method was known as Pasteurization. Hence, he was known as the inventor of the Pasteurization. 

3. Thereafter he also invented fermentation process and developed effective live attenuated vaccines against rabies and anthrax. 

4. He also demonstrated disease of silkworm was due to protozoan parasite.

☝Lord Joseph Lister: 

1. He is known as father of antiseptic surgery. 

2. He also revealed that wound infections were due to microorganisms and discovered the method of destroying microorganisms in the operation theatre by spraying a fine mist of carbolic acid in the air. 

☝Robert Koch: 

He demonstrated the role of bacteria in causing diseases and also invented technique for bacteria isolated from pure culture. 

He only explained first the germ theory of diseases in 1876. 

He prepared gelatin for solid media but was not ideal because gelatin is a protein which is digested by the bacteria and produce a proteolytic exo-enzyme gelatinase that hydrolyses protein into amino acids; thereafter gelatin also melted in temperature more than 25°C. 

There are four Koch’s Postulates viz.: 

(a) The causative agents are surely present in every individual with the disease. 

(b) They must be isolated and grown in pure culture, 

(c) When the pure culture inoculated into an experimental animal it surely cause the disease and 

(d) The causative agent must be re-isolated and re-identified from the experimental animal as well as in pure culture respectively. 

☝Alexander Flemming (1881-1955):

he was the first scientist who discovered World’s first antibiotic substance benzylpenicillin (Penicillin G) from the mould Penicillium notatum in 1928 that destroy many pathogenic bacteria and received Nobel Prize in 1945.

☝Paul Erlich: 

He discovered the treatment of syphilis by using arsenic (Arsphenamine). 

He was the founder of biological standardization with his work on toxins and antitoxins in quantitative manner. 

He also invented the precursor technique to Gram staining bacteria .