introduction to medical micro biology.

History of Medical Micro biology : 

History of Medical Micro biology BY NUZHATH FATIMA Lecturer in Department of Microbiology Jazan university K.S.A

INTRODUCTION : 

INTRODUCTION Medical micro biology : it is a branch of micro biology which deals with the causative agents also called as pathogens (organism causing a disease) of infectious diseases of humans their reactions to them and the methods of protection against such diseases.

History : 

History Bacteria was observed and reported by Antony van leewenhoek as he developed a Microscope in 1776 (40-300x)

Augustino Bassi : 

Augustino Bassi The earliest discovery of pathogenic micro organisms was made by Augustino Bassi in 1835.he showed that the mascardine disease of silkworms was caused by fungus called Beauveria bassiana

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Oliver Wendell Holmes of USA in 1843 and Ignaz semmelweis in vienna in the year 1846 had independently concluded that puerpural sepsis was contagious.

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Casimir Davaine was a french physician. And Polender in 1850 observed anthrax bacilli in blood of animals dying of the disease.

Louis Pasteur (1822-1895) : 

Louis Pasteur (1822-1895) He was a French chemist also referred to as father of microbiology. CONTRIBUTIONS OF LOUIS PASTEUR • Microbial theory of fermentation and proving that all forms of life including microorganisms arise from their like and not spontaneously • Principles and practice of sterilization (showed that microorganisms were inactivated by boiling ,at 120°C under pressure (autoclaved) at 170°C (hot air oven) Development of initial bacteriological techniques He coined the term vaccine. Development of vaccines against: — Anthrax (attenuated anthrax bacilli) vaccine in 1881 — Chicken cholera — Rabies

JOSEPH LISTER : 

JOSEPH LISTER Referred to as father of antiseptic surgery He revolutionised the science of surgery in 1867 by introducing the antiseptic surgical technique He discovered that postoperative application of carbolic acid will reduce the risk of wound infections.he also stated that spraying of carbolic acid on wounds or during operation will also reduce wound infections.

Discoveries of bacteria in 19th Century : 

Discoveries of bacteria in 19th Century A number of of bacteria were discovered in 19th century by a number scientists. Examples 1874 Mycobacterium leprae- Hansen 1879 Neisseria gonorrhoeae- Neisser 1880 Salmonella typhi -Eberth 1881 Staphylococcus- Ogston 1881 Pneumococcus- Pasteur and Sternberg 1882 M. tuberculosis -Robert Koch 1882 Bacillus glanders -Loeffler and Shutz 1883 Vibrio cholerae -Robert Koch 1883 Streptococcus- Fehleisen 1884 C. diphtheriae- Loeffler isolated it and kleb described it in 1881 1885 Clostridium tetani –Nicolaier 1886 colon bacillus-Escherich 1887 Neisseria meningitidis -Weichselbaum 1887 Brucella melitensis- Bruce 1892 Haemophilus influenzae- Pfeiffer 1892 Clostridium welchii -Welch and Nuttall 1894 Yersinia pestis- Yersin and Kitasato 1896 Clostridium botulinum -Ermengem 1896 Shigella -Shiga

ROBERT KOCH : 

ROBERT KOCH Also called as the “Father of modern Bacteriology” He was a medical practitoner in woolstein in east Germany the causative agents of various infectious diseases were being reported by different investigators therefore it was necessary to induce a criteria for proving the claims that organism isolated from a disease is indeed casually related. This criteria was first introduced by Henle which was modified by koch and are known as koch’s postulates

KOCH POSTULATES : 

KOCH POSTULATES according to postulates a micro-organism can be accepted as the causative agent of a infectious disease only if the following conditions are satisfied. 1) The bacterium should be constantly associated with the lesions of the disease. 2) It should be possible to isolate the bacterium in pure culture from lesions. 3) Inoculate of such pure culture into suitable lab animals should reproduce the lesions and disease 4) It should be possible to reisolate the bacterium in pure culture from the lesions produced in the experimental animals. In addition they specific abs to the bacterium should be demonstrated in the serum of the patient suffering from the disease.

The most important adaptation of the Koch’s postulates was made not so long ago, in 1984, by : 

The most important adaptation of the Koch’s postulates was made not so long ago, in 1984, by Stanley Falkow (1934-), an American microbiologist, who adapted them to the level of the gene. The most important adaptation of the Koch’s postulates was made not so long ago, in 1984, by Stanley Falkow (1934-), an American microbiologist, who adapted them to the level of the gene. A gene contributes to the virulence of pathogen bacteria if: The gene is present in strains associated with the disease, not in others Mutation of the gene reduces or ablishes the virulence and complementation in trans must restore it In vivo expression of the gene is demonstrated Specific antibodies are produced and confer at least partial protection

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Many bacteria causing diseases were discover by the end of beginning of the 20th century. But large number of disease such as small pox, chicken pox, measles, influenza,common cold etc were unexplained. Therefore it was Pasteur again during his investigations of rabies in dogs suspected that the disease could be caused by microbe that is too small to be seen even under microscope.

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the existence of such ultra microscopic microbes was proved when ivanosky 1892 reproduced mosaic disease in the tobacco plant by applying to healthy leaves juice from the diseased plants from which all bacteria had been removed by passage through fine filters. Beijerinck ( 1898 ) confirmed these findings and coined the term virus for such filterable infectious agent. loefflers and Frosch 1898 observed that the foot and mouth disease of cattle was also coused by a similar filter passing virus. The first human disease proved to have a virus etiology was yellow fever. Which was transmitted by mosquitoes in humans 1902 by Reed ,Carroll Agramonto and lazear. Popper ( 1909 ) showed that polimyelitis was caused by a filterable virus and transmitted the disease experimentally to monkeys. Dimitri Ivanovski (1864-1920 ) Beijerinck W.Reed

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Investigation of viruses and diseases caused by them was done extensively due to the introduction of electron microscope by Ernst Ruska (1931-1934) can see particles of even 10 A0 .due to which the morphology of different viruses causing the diseases were studied. Cultivation of viruses was possible only in animals or in human volunteers till the technique of growing them on chick embryos was developed by Good pasture in 1930. The possibility that virus infection could lead to malignancy was first put forth of by Ellerman and Banal in 1908. Twort 1915 and Heralls discovered the lytic phenomenon in bacterial cultures. and the agents responsible were termed as bacteriophages. Ernst Ruska Frederick William Twort Dr. Ernest Goodpasture

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John enders 1949 and others developed living human and animal cell cultures. Marywortley Mantagu Artificial immunization Edward Jenner used cow pox virus as a vaccine against small pox in 1796.

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the efficiency of killed bacteria in inducing immunity was discovered by salmon and smith in 1886 Lowenstein in vienna produced diptheria toxoid used againt diptheria. salmon

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