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vendredi 2 décembre 2011

A Page of History of Microbiology

A Page of History of Microbiology

A page of history of the formidable adventure of discovered the infinitely small one

Table des matières

Salim Djelouat
Professor Medical Analyses and Medical bacteriology / Scientific Author / knolAuteur
BY Salim Djelouat     


Had arrived at the conclusion that the animals and the plants, however complex are, are made of few elements which are repeated in each one of them.  And even the postulate of the idea of an invisible contagion by infectious agents posed, but could not bring the proof.
Centuries later, with the invention of the lens then microscope, it was possible to confirm these assumptions by the direct observation.

1546, GIROLAMO FRACASTORO (1483-1553):

Doctor and Italian poet, more known much more, for his treaties of philosopher and about the Latin poems, speak about “séminaria” name for alive germs which would be at the origin of certain diseases. 
It is besides in one of its poems that it draws the name from syphilis.
In Italy and at this same time, the prostitutes were already supervised to avoid the transmission of this disease.
At this same time the concepts of rules of hygiene that we know today, were practically non-existent


Affirmed the existence of invisible alive germs, but their ideas hardly had success. 

IN 1590/98, Dutch ZACHARIAS JANSEN and his HANS son:  

Benefitting from their competences of manufacturer of lenses, invents an optical system which will upset biology: the microcroscope.  

IN 1658, ATHANASIUS KIRCHER (1602-1680):  

A German Jesuit, affirmed to have observed under the microscope in the blood of the patients “an innumerable blossoming of worms which are unperceivable with the eye”, persons in charge according to him for the plague.

IN 1660, ANTON VAN LEEUWENHŒK (1632/1723):

With open the way to the scientific exploration of the small whole and this thanks to the modifications which it made to the microscope created by the Jansen family.   It was thus one of the first to describe bacteria and the protozoa, to detect the blood corpuscles and circulation in the frog legs and to observe nervous fibres and the cells of the skin. It was thus the first to describe the microbes.

IN 1665, ROBERT HOOKE (1635-1703): 

Discover the cell and this thanks to the modifications made to the microscope. In its work entitled “Micrographia”, gone back to 1667, it named “cells” the smallest units structural of the life. 
The discovery of Hooke marked the beginning of the cellular theory, according to which all the alive beings are made of cells.

IN 1796, EDWARD JENNER (1749-1823):  

Had discovered that the injection of a preparation of vaccinates, the shape of benign variola of the cow, at the time protects the man against human variola, very widespread.  It should be noted that the Chinese had discovered this phenomenon of the hundreds of years earlier. 


Naturalist and German zoologist, use for the first time the term of bacterium.  During nearly 30 years Ehrenberg examines water samples, of ground, sediments and rocks, which enables him to describe several hundreds of new species, inter alia whipped such as Euglena, of ciliés: Paramecium aurelia and Paramecium caudatum and a great number of tiny fossils, which it describes in nearly 400 publications.  It is particularly interested by a group of the protists: diatoms, but it also studied and named many species the radiolarian ones. Before Ehrenberg does not make its studies it is not known that considerable masses of rocks are made up of tiny species of animals or plants.  It as showed as the phosphorescence of the seas is due at living organisms.
He is the first holder of the Leeuwenhoek medal in 1877.


The bond between infectious diseases and microbes had already established.  It was interested in a disease of the silkworm and discovered that it was due to a mushroom and that it was contagious. 
In 1844 it drew the similar conclusions concerning measles, syphilis, the plague and the variola which it allotted to “alive parasites”. 
This work however did not have any audience in the scientific world and he died completely been unaware of.

IN 1839, MATTHIAS SCHLEIDEN (1804-1881) and THEODOR SCHWANN (1810-1882):

Established the cellular theory, according to which all the organizations - that they are simple like the Bacteria or complexes like the higher plants and animals - are made of cells and cellular products.  Some of them are made of a single autonomous cell (they are the unicellular organizations), while others are made of several cells differentiated from the point of view of the form and the functions (they are the pluricellular organizations).


This scientist was the first to cultivate microbes by using a nutritive medium.  It made push micro-organisms in gravy placed in a bottle. 
It showed on this occasion which the microbes do not push if the gravy were boiled and remains safe from the air. 
On the other hand, if the liquid comes in contact with the air, the microbes develop.  It thus refuted the theory of the spontaneous generation held for acquired at that time. 
However, the battle of the spontaneous generation will still have beautiful days since Pasteur will harness himself with the same task one century later.
It should besides be noted that it will use techniques very similar to those implemented before him by SPALLANZANI.  Lastly, our abbot, definitely very fertile, showed that the microbes multiply while being divided into two, then still in two.  This is why they invade the culture medium quickly.  Following work of Spallanzani, various enquiring and microbes describe observe while the microscopes but their ecological importance improve, epidemiologic and economic remainder unsuspected.

IN 1846, IGNACE SEMMELWEIS (a Hungarian obstetrician): 

Succeeds in making pass in its maternity the mortality of been confined from 27% to 0.23% simply by requiring midwives and medical students charged to examine the patients whom they wash the hands with bleach.  The discovery of the antisepsy is not worth any recognition to him: requiring of its owner that it is subjected to the same hygiene, it is revoked.  Become insane, he will die of an infection following a cut made during a dissection.  The novelist CELINE made of it his thesis of doctorate in medicine.

IN 1863, OF CASIMIR DAVAINE (1812-1882):  

Contrary to work of Agostino Bassi started a polemic. 
It shows that the coal of the sheep is due to a bacterium and that it can be transmitted in experiments to rabbit. 
But its results were inconstant and the disease located at quite precise zones. 
Its contradictors claim that the presence of the bacteria in blood is a consequence and not the cause of the disease.


ROBERT KOCH (1843-1910) German doctor:  

Solves the enigma by showing that the bacillus of coal forms spores, bodies of resistance able to survive in the grounds and to infect new animals while developing to with it.  R. Koch can be regarded as the true founder of microbiology. It is him which developed the principal methods still used today:  nutritive mediums adapted to all kinds of bacteria culture of the bacteria on solid medium specific colourings etc   One owes him, amongst other things, the discovery of the bacillus of the tuberculosis and the vibrio of the cholera.   But, in France and almost a little everywhere in the world, it is the name of PASTEUR who remains attached to the birth of microbiology.

1857-1876: LOUIS PASTEUR    

Highlights the roles of the micro-organisms in lactic and alcoholic fermentation. It develops the techniques of pasteurization and sterilization allowing him the installation of pure cultures of micro-organisms. 
The possibility of culture made it possible to show that the spontaneous generation was an aberration.

1877-1895: LOUIS PASTEUR:  

Show that diseases are the consequence of the presence of these micro-organisms. 
It was persuaded that certain contagious diseases could be due also to micro-organisms. 
Not being a doctor, he did not want to launch out in their study when the ministry for agriculture required of him to study the pébrine, contagious disease of the worms with silk and economic danger.
After having solved this problem, it attacked other contagious diseases.  It then discovered the micro-organisms agents of various diseases as well of the Man as of the animals (staphilococcus of the furoncles and osteomyelitis, streptocoque of the fever puerpérale, this disease fought by measurements of antisepsy of Semmelweis, cholera of hens etc).

1880/81, LOUIS PASTEUR:  

By studying the cholera of hens, it discovers that the injection of a out-of-date preparation of the microbe protects the animals against the infection.  It calls the phenomenon “vaccination” in homage to EDWARD JENNER On May 31, 1881, in front of a crowd of journalists, doctors and veterinary surgeons; it injects a virulent coal culture with 48 sheep whose 24 received an attenuated preparation as a preliminary.  2 days later, 22 of the untreated sheep died, 2 are with the anguish while the 24 vaccinated remain quite alive.

1882: ROBERT KOCH:  

The bacillus responsible for tuberculosis (Mycobacterium tuberculosis) highlights. It laid down the rules (always used) which make it possible to show rigorously that a given bacterium is at the origin of an infection. In 1883, during forwarding in Egypt, It isolates the microbial agent from the cholera (Vibrio cholerae) with the assistance from GAFFKY and BERNHARD FISCHER.  It proves, a little later the role of water in the transmission of the disease


Develop a technique of colouring which is used in the study and the classification of the bacteria in two great groups: negative the positive Gram bacteria and that Gram (you also you will have very blue fingers…).


Discover the first effective treatment (arsenic derivative) against syphilis. It is the first time that one treats with an agent chimiotherapeutic a bacterial disease.


Discover the first bacteriophages   


Discover the bacterial transformation and establishes the bases of the molecular genetics. 


Discover the properties antibactériennes penicillin produced by Penicillum.  Humanity enters the era of antibiotics.


Discover another antibiotic: the streptomycine which will be used soon against tuberculosis.  

1960: FRANÇOIS JACOB, DAVID PERRIN, CARMEN SANCHEZ AND JACQUES MONOD:   Propose the concept of opéron for the control of the form of bacterial genes.


Study the ribosomal ARN to discover a third form of life, Archaea, genetically distinct from the bacteria and eucaryotes.   

1986: KARY MULLIS:  

Invent the technology of P.C.R (Polymerase Chain Reaction), by using an enzyme of the bacterium Thermus aquaticus.   


Made a success of the complete sequencing of the first bacterial genome (Haemophilus influenzae). Microbiology enters the era of the génomique one. 

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