This document discusses the history and development of microbiology. It covers key topics such as: - The early discovery of microorganisms in the 1600s by Antonie Van Leeuwenhoek. - Louis Pasteur's experiments in the 1800s that disproved spontaneous generation and established germ theory. - Robert Koch's work in the late 1800s isolating specific bacteria that cause diseases and establishing his postulates for proving causation. - Early pioneers like Edward Jenner and developments like vaccines, antibiotics like penicillin, and the golden age of microbiology from 1857-1914.

1. Dr.D.W.DeshkarDr.D.W.Deshkar
Assistant ProfessorAssistant Professor
Dept. of MicrobiologyDept. of Microbiology
D.Y.Patil Medical College, Kolhapur.D.Y.Patil Medical College, Kolhapur.

2. Microbiology (from Greek μ κρος,ῑ
mīkros, "small"; βίος, bios, "life"; and
-λογία, -logia) is the study of
microorganisms, which are microscopic,
unicellular, and cell-cluster organisms.

3. Medical Microbiology is the study of microbes
that infect humans, the diseases they cause,
their diagnosis, prevention & treatment.
It also deals with the response of the human
host to microbial and other antigens.
Microbes, or microorganisms are minute living
things that are usually unable to be viewed
with the naked eye.

4. Why is it Important?
Infection is one of the most important
causes of mortality and morbidity in the
population.
Approximately 30% of hospital patients
are on antibiotics at any one time
1 in 10 patients acquires an infection
whilst in hospital.

5. Bacteria, fungi, protozoa, algae,
viruses are examples!
Some are pathogenic.

6. Some organisms studies by microbiologists CAN be
visualized without the aid of amplification [bread
molds (fungus) and filamentous algae]
 These organisms are included in the discipline of
microbiology because of similarities in properties
and techniques used to study them
Techniques necessary to isolate and culture
microorganisms
 Isolation
 Sterilization
 Culture in artificial media

7. Microbiologists may be interested in
specific types of organisms:
 Virologists - viruses
 Bacteriologists - bacteria
 Phycologists or Algologists - algae
 Mycologists - fungi
 Protozoologists - protozoa

8. Microbiologists may have a more
applied focus:
 Medical microbiology, including
immunology
 Food and dairy microbiology
 Public health microbiology
 Industrial microbiology
 Agricultural microbiology

9. Microbiologists may be interested in various
characteristics or activities of microorganisms:
 Microbial morphology
 Microbial cytology
 Microbial physiology
 Microbial ecology
 Microbial genetics and molecular biology
 Microbial taxonomy

10. The existence of microorganisms was
hypothesized for many centuries before
their actual discovery. The existence of
unseen microbiological life was
postulated by Jainism which is based on
Mahavira’s teachings as early as 6th
century BCE.

11. Early Discoveries
Lucretius, a Roman philosopher (98-55 B.C.),
and Girolamo Fracastoro, a physician (1478-
1553) believed invisible creatures were
responsible for disease
Franscesco Stelluti observed bees and weevils
using a microscope in the early 1600s

12. Paul Dundas notes that Mahavira asserted
existence of unseen microbiological creatures
living in earth, water, air and fire.
Jain scriptures also describe nigodas which are
sub-microscopic creatures living in large
clusters and having a very short life and are
said to pervade each and every part of the
universe, even in tissues of plants and flesh of
animals

13. The Roman Marcus Terentius Varro made
references to microbes when he warned
against locating a homestead in the vicinity of
swamps "because there are bred certain
minute creatures which cannot be seen by the
eyes, which float in the air and enter the body
through the mouth and nose and there cause
serious diseases."
Concept of “Animalia minuta”
History of Microbiology

14. History of Microbiology
The first microbes were observed in 1673.
In 1665, Robert Hooke (Englishman)
reported that living things were
composed of little boxes or cells.

15. History of Microbiology
1673-1723, Antony van
Leeuwenhoek (Dutch)
described live
microorganisms that he
observed in teeth scrapings,
rain water, and peppercorn
infusions.

16. History of Microbiology
Spontaneous Generation
 The belief that life could originate
from non-living or decomposing
matter

17. History of Microbiology
Spontaneous Generation Supported by:
 Aristotle (384-322 BC) – Believed that imple
invertebrates could arise by spontaneous generation
 John Needham (1713-1781) – Boiled mutton broth,
then sealed and still observed growth after a period
of time
 Lazarro Spallanzani (1729-1799) No growth in
sealed flask after boiling – proposed that air was
needed for growth of organisms
 Felix Pouchet (1859) – Proved growth without
contamination from air

18. History of Microbiology
Spontaneous Generation Disproved by:
 Francesco Redi (1626-1697) – maggot
unable to grown on meat if meat was
covered with gauze
 Schwann, Friedrich Schroder and von Dusch
(1830s) – Air allowed to enter flask but only
after passing through a heated tube or
sterile wool
 John Tyndall (1820-1893) – Omission of
dust  no growth. Demonstrated heat
resistant forms of bacteria (endospores)

19. History of Microbiology
Many believed spontaneous generation:
life can arise from non-living matter.
In 1668, the Italian physician Francesco
Redi performed an experiment to
disprove spontaneous generation.
Can you think of an experiment that
could disprove spontaneous generation?

20. Redi filled six jars with decaying meat.
History of Microbiology
Conditions Results
3 jars covered with fine net No maggots
3 open jars Maggots appeared
From where did the maggots come?
What was the purpose of the sealed jars?
Spontaneous generation or biogenesis?

21. Jar-1
Left open Maggots
developed
Flies were
observed laying
eggs on the meat
in the open jar
Jar-2
Covered with
netting Maggots
appeared on the
netting
Flies were
observed laying
eggs on the
netting
Jar-3
Sealed No
maggots
developed
History of Microbiology

22. Rudolf Virchow (German) presented
biogenesis: living cells can arise only from
preexisting cells.
So now there are two hypotheses:
1. The hypothesis that living organisms arise from
nonliving matter is called spontaneous generation.
According to spontaneous generation, a “vital force’
Forms life.
2. The Alternative hypothesis, that the living organisms
arise from preexisting life, is called biogenesis.
History of Microbiology

23. 1861: Louis Pasteur demonstrated that
microorganisms are present in the air.
History of Microbiology
Conditions Results
Nutrient broth placed in
flask, heated, not sealed
Microbial growth
Nutrient broth placed in
flask, heated, then sealed
No microbial growth
Spontaneous generation or biogenesis?

24. The Golden Age of
Microbiology
1857-1914
Beginning with
Pasteur’s work,
discoveries included the
relationship between
microbes and disease,
immunity, and
antimicrobial drugs
History of Microbiology

25. Louis Pasteur (1822 - 1895) – A trained
chemist of France. Studies on
fermentation created interest in microbiology

26. History of Microbiology
Pasteur showed that microbes are responsible
for fermentation.
Fermentation is the conversation of sugar to
alcohol to make beer and wine.
Microbial growth is also responsible for
spoilage of food.
Bacteria that use alcohol and produce acetic
acid spoil wine by turning it to vinegar (acetic
acid).

27. History of Microbiology
Pasteur demonstrated
that these spoilage
bacteria could be
killed by heat that
was not hot enough
to evaporate the
alcohol in wine. This
application of a high
heat for a short time
is called
pasteurization.

28.  Louis Pasteur (1822 - 1895)
 trapped airborne organisms in cotton;
 he also heated the necks of flasks, drawing them
out into long curves, sterilized the media, and left
the flasks open to the air;
 no growth was observed because dust particles
carrying organisms did not reach the medium,
instead they were trapped in the neck of the
flask; if the necks were broken, dust would settle
and the organisms would grow; in this way
Pasteur disproved the theory of spontaneous
generation
History of Microbiology

29. History of Microbiology
Louis Pasteur ( 1822 – 1895) : Known as “ Father of
Microbiology”. His important contributions –
1.Development of methods & techniques of microbiology.
2.Conclusively proved that all forms of life arose only from like
& not de novo.
3.He disapproved the view of spontaneous generation of life
through his experiments performed in swan necked flasks.
4. Introduction of sterilization techniques & development of
steam sterilizer, autoclave & hot – air oven.

30. History of Microbiology
5.Studies on anthrax, chicken cholera, & hydrophobia.
6. During studies on Rabies he could not isolate any organism
from man & dog but suggested that the causative agent of
rabies is ultramicroscopic.
7. He introduced attenuated live vaccine for prophylactic use.
An accidental observation that chicken cholera bacillus culture
left for several weeks lost their pathogenicity but retained their
ability to protect the birds against subsequent infection. -
development of the concept of attenuation & development of
live vaccine.

31. History of Microbiology
8.He attenuated the anthrax bacillus by incubation at high
temperature (42 – 430
C)& proved that inoculation of such
bacilli in animals induced specific protection against anthrax.
9. He convincingly demonstrated the protective role of anthrax
vaccine in a public expt.(1881) where vaccinated sheep, goats
& cows were challenged with a virulent anthrax bacillus
culture. All the vaccinated animals survived while an equal
number of unvaccinated control animals died . Coined the term
vaccine for such preparations.
7. He introduced attenuated live vaccine for prophylactic use.

32. The Germ Theory of Disease
1835: Agostino Bassi showed a silkworm disease
was caused by a fungus.
1865: Pasteur believed that another silkworm
disease was caused by a protozoan.
1840s: Ignaz Semmelwise advocated hand washing
to prevent transmission of puerperal fever from
one OB patient to another.
History of Microbiology

33. The Germ Theory of Disease
M. J. Berkeley (ca. 1845)
 demonstrated that the Great Potato Blight
of Ireland was caused by a Fungus
History of Microbiology

34. The Germ Theory of Disease
• 1860s: Joseph Lister used a chemical disinfectant to
prevent surgical wound infections after looking at Pasteur’s
work showing microbes are in the air, can spoil food, and
cause animal diseases.
Joseph Lister (1827 - 1912)
 developed a system of surgery designed to prevent
microorganisms from entering wounds – phenol sprayed in air
around surgical incision
 Decreased number of post-operative infections in patients
 his published findings (1867) transformed the practice of
surgery
History of Microbiology

35. The Germ Theory of Disease
Charles Chamberland (1851 - 1908)
 identified viruses as disease-causing agents – Tobacco
Mosaic Virus
Edward Jenner (ca. 1798)
 used a vaccination procedure to protect individuals
from smallpox
Louis Pasteur
 developed other vaccines including those for chicken
cholera, anthrax, and rabies
History of Microbiology

36. History of Microbiology
The Germ Theory of Disease
1876: Robert Koch provided proof that a
bacterium causes anthrax and provided
the experimental steps, Koch’s postulates,
used to prove that a specific microbe
causes a specific disease.
Koch was a physician and Pasteur’s young
rival

37. A young milkmaid informed the physician Edward
Jenner that she could not get smallpox because
she had already been sick from cowpox.
1796: Edward Jenner inoculated a person with
cowpox virus. The person was then protected
from smallpox. Called vaccination from vacca for
cow
The protection is called immunity
History of Microbiology

38. Chemotherapy – treatment with chemicals
Chemotherapeutic agents used to treat infectious
disease can be synthetic drugs or antibiotics.
Antibiotics are chemicals produced by bacteria
and fungi that inhibit or kill other microbes.
Quinine from tree bark was long used to treat
malaria.
History of Microbiology

39. Chemotherapy – treatment with chemicals
1910: Paul Ehrlich developed a synthetic arsenic
drug, salvarsan, to treat syphilis.
1930s: Sulfonamides were synthesized.
History of Microbiology

40. History of Microbiology
1928: Alexander Fleming
discovered the first
antibiotic.
He observed that
Penicillium fungus
made an antibiotic,
penicillin, that killed
S. aureus.
1940s: Penicillin was
tested clinically and
mass produced.

41. AngelinaAngelina HesseHesse
Development of
Agar Used to Grow
Microorganisms.

42. Although the
microscope was
invented in the
1600’s, it took 200
years for scientists to
discover its use in
isolating and
identifying specific
microbes for a
particular disease.

43. Koch’s Postulates
The specific causative agent must be found in
every case of the disease.
The disease organism must be isolated from the
lesions of the infected case and maintained in
pure culture.
The pure culture, inoculated into a susceptible or
experimental animal, should produce the
symptoms of the disease.
The same bacterium should be re-isolated in pure
culture from the intentionally infected animal.
The specific antibodies to the bacterium should
be demonstrable in the serum of patients
suffering from the disease.

44. Isolation of Important Bacteria in
the Late 19th
Century
1882 – Tubercle bacillus ( Koch)
1883 - Cholera Vibrio ( Koch )
1883 - Diphtheria Bacillus ( Klebs , Loeffler )
1886 - Pneumococcus ( Frankel)
1887 - Meningococcus ( Weichselbaum )

45. Thank you