Louis Pasteur and Robert Koch were pioneers in microbiology who made seminal contributions. Pasteur disproved the theory of spontaneous generation, invented pasteurization, and developed vaccines including for rabies and anthrax. He founded the Pasteur Institute. Koch developed techniques like staining and solid media culture which allowed isolation of bacteria. He identified the bacteria that cause anthrax, tuberculosis, cholera and other diseases and formulated Koch's postulates. Both scientists greatly expanded understanding of microbes and infectious disease.

1. CONTRIBUTIONS OF LOUIS PASTEUR AND ROBERT KOCH
SAROTHIKA D
1st year M.Sc Microbiology
Register NO: 20316004
FUNDAMENTALS OF MICROBIOLOGY

2. Contributions of Louis Pasteur
FATHER OF MODERNMICROBIOLOGYAND BACTERIOLOGY
• Louis Pasteur was a French Biologist, Microbiologist
and Chemist born on December 27, 1822.
• His discoveries and inventions laid strong foundation
for the development of Microbiology.
• His era is known as “GOLDEN AGE OF
MICROBIOLOGY”.
• They are many methods and techniques which are
contemporarily used in many fields.
• He is considered as one of the profound scientists and
earned world wide popularity and recognition.
• Also known as “FATHER OF FOOD MICROBIOLOGY”

3. SPONTANEOUS THEORY:
• Scientists such as ARISTOTLE, FRANCESCO REDI, JOHN
NEEDHAM, LAZARO SPALLANZANI, FRANZ SCHULZE and
THEODOR SCHWANN put forth their ideas about Spontaneous
theory from (322 BC – 1872)
• Louis Pasteur disapproved this theory “Living things arose
from non-living matters” by performing “ Swan
Necked Bottle Experiment” and ended the controversy.
• Later John Tyndall supported Pasteur’s discovery
and prepared a devised an apparatus to
demonstrated that “air had the ability to carry
particulate matter”.
• Thus, it is known as “Doctrine of Spontaneous Generation”

4. INTERPRETATONS OF PASTEUR AS FOLLOWS:
• Pasteur used both Swan Necked Flask and Straight Necked Flask in his
experiments.
• Both flasks were filled with broth, kept opened for observation.
• Broth in the Swan Necked Flask was sterile where Straight Necked was
contaminated with microbes.
• The bend present in the swan bottle neck contains microbes but the broth was
sterile.
• Thus Pasteur concluded “Dust particles or the germs present in the air enter
into the solution and micro organisms growth was further supported”.
• This is known as “Law of Biogenesis” and concluded that “life comes only from
previously existing life”.

5. FERMENTATION:
• When Pasteur began his career as Chemistry Professor at University of Lille, France he researched
and learned about the Production and Process involved in the Manufacture of Beer and Wine.
• To help his neighbor for the consistent production of beer and wine, he worked and discovered
FERMENTATION.
• RESULTS OF HIS DISCOVERIES ARE:
1. Fermentation of fruits and grains resulting in alcohol was brought
about “MICROORGANISMS”.
2. Microbes are the only reason for the best or bad quality of beer or
wine.
3. He also sorted out microbes based on their production ‘poor quality and
good quality’.
4. He also studied the metabolism of few micro organism and their fermentation process .
5. From that Pasteur improved the strains of good quality microbes to ramp up the production.

6. PASTEURIZATION:
• From fermentation Pasteur suggested that undesirable types of
microbes might be removed by ‘HEATING’ that would not spoil the
flavor of the fruit juice, but enough to destroy high percentage of
microbial population.
• Holding juices at 62.8C (145 F) for half an hour will kill the harmful
or undesirable microbes that spoils the production.
• This technique is known as Pasteurization.
• But still pasteurization is not a sterilization process it does not kill
spores and some of the microbes.
• Currently, this the broadly used technique in the diary industries to
maintain the quality and shelf life of milk and related products as
cheese, curd, butter etc..,
• We have come across the word “PASTEURIZED MILK”.

7. GERM THEORY:
• Many believed that “Microbes are the reason for the diseases.” Adding point to the statement Pasteur
conducted experiments between 1860-1864.
• He discovered the pathology of puerperal fever and the pyrogenic vibrio in the blood where he suggested to use
boric acid to kill these micro organisms before and after confinement.
• Pioneer in the use of “Antispetics in obstetrical practice”.
SILK WORM:
• Solving the problem of fermentation, French Government requested him to give solution for the silkworm
diseases PEBRINE.
• Following continuous failure and disappointments, he rescued the industries from a certain protozoan disease
and also developed methods to screen out infected worms to provide supply of healthy.

8. VACCINATION FOR HUMANS AND ANIMALS:
• While working with chickens, Pasteur left cultures of fowl cholera in his laboratory and
went on vacation.
• When he came back, inoculated the chickens with the left over culture. Further, chickens
did not contract cholera.
• Later he inoculated those chickens with ‘live fresh strain of fowl cholera’ and still no
infection found.
• There Pasteur realized that ‘weakened strains of viruses could immunize against
diseases’.
• Repeating the experiments again, he concluded the microbes which cause serves itself as
a remedy to a particular disease, if the strains got weakened.
• That was how vaccination for the first time developed against cholera.

9. ANTHRAX VACCINE:
• After cholera, Pasteur shifted his experiments to anthrax which was affecting
cattle.
• In his experiment, Pasteur gave 25 animals two shots of an anthrax
vaccine he had created with weakened anthrax bacteria.
• After he gave both rounds of the vaccine to these animals, he injected them
with live anthrax bacteria.
• Group 1:
Healthy cows + Attenuated anthrax vaccine from infected cow.
• Group 2:
Healthy cows + Without vaccination
(AFTER A WEEK)
• Group 1:
Vaccinated cows + Live Anthrax bacteria (Cows were survived).
• Group 2:
Cows without vaccination + Live Anthrax bacteria (Cows were died).
• Pasteur conducted this experiment publically and earned reliance of the
people.
• And also he isolated Anthrax Bacteria.

10. WORK ON RABIES VACCINE:
• Pasteur suspected that the agent caused rabies was a ‘strange microbe’ (later it was discovered to be virus,
a non-living entity).
• Difficulties such as, it could not viewed under normal light microscope so the experimentation with the
disease demanded the development of entirely new methodologies.
• Pasteur conducted his experiment in rabbits by transmitting the infectious agent, he inoculated in
intracerebral inoculations.
• While experimenting unkowingly , instead of attenuated live micro organisms, a neutralized agent and
opened the way for second class of vaccines, known as *inactivated vaccines*
• This era is also known as “ERA OF PREVENTIVE MEDICINE”.
• This was injected into 9 year old boy affected by dog bite and it was a great victory.
• Thus glory of Pasteur reached zenith.

11. IMPLICATIONS OF PASTEUR’S WORK:
• Once he was given with the theoretical basis of a process, he
tried many other ways to develop it for industrial applications.
• Theoretical implication of his later research, which emerged
from his attenuation procedure for vaccines, that virulence is
not a constant attribute but a variable property; it can be lost
and later recovered.
• Virulence could be decreased, but Pasteur suspected that it
could be increased well.
• Increased virulence is the reason for the epidemic or
pandemic.
• Pasteur was the first to recognize variability in virulence.
• Today this concept remains relevant tot the study of infectious
disease, especially with regard to understanding the
emergence of disease such as Bovine Spongiform
Encephalopathy(BSE), Severe Acute Respiratory Syndrome
(SARS) and Acquired immunodeficiency Syndrome (AIDS).
• Many modern methods had developed by the implication
theories of Pasteur.

12. PASTEUR INSTITUTE (FRANCE)
• Pasteur Institute (French: Institut Pasteur) is a French non-
profit private foundation dedicated to the study of biology, micro-
organisms, diseases, and vaccines.
• It is named after Louis Pasteur, who made some of the greatest
breakthroughs in modern medicine at the time,
including pasteurization and vaccines for anthrax and rabies.
• The institute was founded on June 4, 1887, and inaugurated on
November 14, 1888.
• For over a century, the Institut Pasteur has been at the forefront
of the battle against infectious disease.
• This worldwide biomedical research organization based
in Paris was the first to isolate HIV, the virus that causes AIDS,
in 1983. Over the years, it has been responsible for
breakthrough discoveries that have enabled medical science to
control such virulent diseases
as diphtheria, tetanus, tuberculosis, poliomyelitis, influenza, yell
ow fever, and plague.
• Since 1908, ten Institut Pasteur scientists have been awarded
the Nobel Prize for medicine and physiology—the 2008 Nobel
Prize in Physiology or Medicine was shared between two
Pasteur scientists

13. CONTRIBUTION OF ROBERT KOCH
FATHER OF MEDICAL MICROBIOLOGY
• Robert Koch was born on December 11,1843 at
Germany.
• He was an outstanding student in his young age.
• Koch had keen interest in the field of Medical and was
graduated as a doctor.
• He was highly influenced by his Professor “Jacob
Henle” published paper about “Infectious diseases
were caused by living, parasitic organisms”.
• He had also cleared enormous German Government
Exams and became front rank scientific worker.
• His era is known as “Golden age of Bacteriology”.

14. ANTHRAX:
• He was highly influenced by his Professor, it was a point Koch began his
experiments.
• He cultivated the anthrax organisms in suitable media and viewed
under microscope slides, demonstrated their growth into long
filaments, and discovered the formation within them of oval,
translucent bodies—dormant spores.
• Koch found that the dried spores could remain viable for years, even
under exposed conditions.
• The finding explained the recurrence of the disease in pastures long
unused for grazing, for the dormant spores could, under the right
conditions, develop into the rod-shaped bacteria (bacilli) that cause
anthrax.
• The anthrax life cycle, which Koch had discovered, was announced and
illustrated at Breslau in 1876, on the invitation of Ferdinand Cohn, an
eminent botanist.
• Julius Cohnheim, a famous pathologist, was deeply impressed by
Koch’s presentation. “It leaves nothing more to be proved,” he said.
• He had studied the morphology and life cycle including spore
formation elaborately.

15. TECHNOLOGICAL PROGRESS:
• For Koch microscopy was much challenging because of “poor illumination” of
bacteria were transparent and mobile in fluid.
• Then he discovered to fix a bacteria to a slide by drying them in liquid
solution.
• By applying aniline dyes-eosin, fuchsin, safranin and methyl violet- he could
visualize bacteria more easily and detect morphological traits distinctly.
• Then, developed the resolution and illumination of the microscope and
become first person to use oil immersion, man to publish photographs of
bacteria.
• Now a days, the routine microscope used by us was discovered by him.
• With this invention he studied detail about septicemia, gas gangrene, abscess
at microscopic level.
• Also found each diseases is caused by different micro organisms and they
differ among each other distinctly.
• He also developed “Pure culture technique” and “Liquid media”.
• His one of the co- workers Julius Petri invented “Petri Plate”.
• He used the bacterial colonies to various chemicals and found the method “
Chemical Sterilizaton”.

16. Procedures:
• Importance of disinfection and sterilization was studied and
practiced.
• He also studied certain chemicals kills bacteria others
merely inhibits the bacterial growth.
• It was also known as “Antibiotic Era”.
• In 1881, Plate technique was clearly explained where others
could replicate and study the microorganism.
• This paper of Koch became “ Bible of Bacteriology”.
• He also discovered Diptheria bacillus and Typhoid bacillus.

17. TUBERCULOSIS (Tb):
• TB became much prevalent and remained enigmatic ,
preliminary studies established its transmissibility, but not
a causative agent.
• By suspecting, he used Methylene Blue Stain, he detected
few tiny rods in tuberculosis tissue.
• When he added a brown counterstain for photographic
contrast, more bacteria was not invisible.
• Here he consolidated the functions of stains used when it
come to contact with air.
• He also discovered tubercle bacillus which was a slow
growing bacteria and it can be isolated from the sputum
of infected person.

18. KOCH POSTULATES:
• The bacteria must be present in every case of the
disease.
• The bacteria must be isolated from the diseased
host and grown in pure culture.
• The specific disease must be reproduced when a
pure culture of the bacteria is inoculated into a
healthy susceptible host.
• Again the bacteria must be recoverable from the
experimentally infected host.
LIMITATIONS:
• However, Koch's postulates have their limitations
and so may not always be the last word. They may
not hold if:
• The particular bacteria (such as the one that causes)
cannot be "grown in pure culture" in the laboratory.
• There is no animal model of infection with that
particular bacteria.

19. A harmless bacteria may cause disease if:
• It has acquired extra virulence factors making it pathogenic.
• It gains access to deep tissues via trauma, surgery, an IV line,
etc.
• It infects an immunocompromised patient.
• Not all people infected by a bacteria may develop disease-
subclinical infection is usually more common than clinically
obvious infection.
• Despite such limitations, Koch's postulates are still a useful
benchmark in judging whether there is a cause-and-effect
relationship between a bacteria (or any other type of
microorganism) and a clinical disease.
• His findings were also became a controversy topic which was
researched by many scientists.
• Some case of micro organism it is completely applicable or
partially applicable or stays exceptional.
• Eg: Mycobacterium tuberculosis , Treponema pallidum.

20. CHOLERA:
• Koch next turned his attention to cholera, and began to conduct research
in Egypt in the hopes of isolating the causative agent of the disease.
• However, he was not able to complete the task before the epidemic in
Egypt ended, and, after a short trip to Persia, traveled to India to continue
with the study.
• In 1884 in Bombay state of India (the present day State of Maharastra,
India, where he was able to determine the causative agent of cholera,
isolating Vibrio cholera.
• The study was quite uncomplicated with little or no epithelial damage.
• Comma- shaped bacillus was identified.
• Using different media Koch and fast-growing without spore formation.
• With nourishment it could survive outside the body.
• He attributed this as poison and explained how bacteria could cause
disease with little or no penetration of the intestinal wall.

21. Conclusion for cholera:
• After conducting repetitive experiments, he found hygienic issues
are the cause for the cholera.
• He concluded that affected patients used a water tank that is
contaminated for washing, drinking and for other purposes.
• Due to nourishment of nutrition it sticks to the intestine of the
human.
• This contribution about hygienic is yet followed like bleaching
powders are used to inhibit or kill the microorganisms.

22. TUBERCULIN AND THE WORLD:
• In 1890, Koch began his research for the cure of tuberculosis.
• While working with glycerin extract of tubercle bacilli, he
named as tuberculin.
• Subcutaneous inoculation of the substance in guinea pigs with
tuberculosis caused a reaction not seen in healthy animals.
• In human, he noticed no reaction or mild reaction in healthy
individuals, whereas in patients with active tuberculosis, a
severe reaction occurred characterized by fever, chills and skin
inflammation leading to necrosis.
• Koch believed that afflicted individuals, tuberculin produced a
reaction that slowed or halted disease.
• He also believed that the reaction provided diagnosed
evidence of acute tuberculosis.
• Eventually, a modified version of tuberculin, administered
intracutaneously, would become the standard for diagnosing
latent tuberculosis.
• Koch had demonstrated, but not recognized, the phenomenon
of delayed hypersensitivity and cellular immunity.

23. RESEARCH ACROSS THE COUNTRIES:
• In Italy, Indonesia and New Guinea he
studied about Malaria also established
guidelines for prevention.
• In Trier, Typhoid fever was discovered
explained its carrier state.
• In India, Plague and East Africa- sleeping
sickness was studied.
• In South Africa Koch researched and studied
about Rinderpest, Malaria, sleeping
sickness, horse sickness and relapsing fever.

24. IMPLICATION OF PASTEUR WORKS:
• After the Robert Koch Institute establishment many luminaries gave their contributions to the Microbial world.
• Emilvon Behring discovered Diptheria anti-toxin who co-developed Serum Therapy for Diptheria and Tetanus.
• Shibasaburn kitasato, co-discoverer of bacterium causing Bubonic plague also co- developed Serum Therapy
for tetanus.
• Paul Ehrlich work on hemolysis, auto –immunity and anti-bacterial chemotherapy.
• Richard Pfeiffer co- discoverer of bacteriolysis and pioneered the typhoid vaccine.
• Wassermann established Complement Fixation Test (CFT) for syphilis.

25. ROBERT KOCH INSTITUTE:
• The Robert Koch Institute (RKI) is
a German federal government
agency and research
institute responsible for disease control
and prevention.
• It is located in Berlin and Wernigerode.
As an upper federal agency, it is
subordinate to the Federal Ministry of
Health.
• It was founded in 1891 and is named for
its founding director, the founder of
modern bacteriology and Nobel laureate
ROBERT KOCH.

26. THANK YOU !
SAROTHIKA D
1st year M.Sc Microbiology
Fundamentals of Microbiology
The Gandhigram Rural Institute
Gandhigram
Dindugal