The document provides an introduction and history of microbiology. It discusses the development of the microscope in the 1600s, which allowed early microbiologists like Anton van Leeuwenhoek and Robert Hooke to first observe microorganisms. Important figures that contributed to the field include Louis Pasteur, who developed germ theory and pasteurization; Robert Koch, who developed techniques to isolate and culture bacteria and established Koch's postulates; and Alexander Fleming, who discovered penicillin. The document traces the history from early microscopy observations through the 19th and 20th centuries and the major discoveries that established microbiology as a science.

1. INTRODUCTION & HISTORY OF
MICROBIOLOGY
Dr. S. Mathavi, M.D.,

2. INTRODUCTION
▪ Microbiology is the study of organisms too small to be seen
with the naked eye.
▪ Microorganisms include:
Bacteria
Viruses
Fungi
Protozoa
Helminths (worms)
2

3. COMPARING THE SIZE OF A VIRUS, A BACTERIUM AND AN ANIMAL
CELL
0.25 m
Virus
Animal
cell
Bacterium
Animal cell nucleus

4. MEDICAL MICROBIOLOGY
▪Study of microbes causing human infections
▪Diseases they cause
▪Diagnosis, prevention, treatment
▪Host response - microbes, antigens

5. CAN YOU NAME SOME
❖Bacteria causing human infections
❖Viruses causing human infections
❖Fungi causing human infections
❖Parasites causing human infections

7. BACTERIA

8. FUNGUS

9. VIRUSES

10. PARASITES

11. INFECTIOUS DISEASES

13. IMPACT OF PATHOGENS
❖Nearly 2000 different microbes cause diseases
❖10 billion infections/ year worldwide
❖13 million deaths from infections worldwide

14. HOW DO YOU VISUALIZE THESE ORGANISMS?
Microscope

15. HISTORY OF MICROSCOPE
•The study of microorganisms was dependent on microscopes
•The microscope was available during the mid‐1600s
•In 1609, while trying to develop his telescope, Galileo Galilei used
lenses with a shorter focal length to turn his telescope into a microscope
that could be used to magnify small objects
•In 1665, an English scientist named Robert Hooke observed strands of
fungi among the specimens of cells he viewed

16. •In the 1670s and the decades thereafter, a Dutch merchant named Anton van
Leeuwenhoek made careful observations of microscopic organisms, which he
called animalcules
•Until his death in 1723, Van Leeuwenhoek revealed the microscopic world to
scientists of the day
•Regarded as one of the first to provide accurate descriptions of protozoa, fungi,
and bacteria

17. ANTONY VAN LEEUWENHOEK
❖Draper in Delft, Holland
❖Grinding lenses
❖1683 - description of various bacteria
❖Observed diverse material
❖Communicated to Royal Society of
London

20. CULTURE

23. STERILIZATION

25. LOUIS PASTEUR- FATHER OF
MICROBIOLOGY
❖1822-1895; France
❖Fermentation
❖Sterilisation
❖Steam steriliser
❖Hot-air oven
❖Autoclave
❖Studied – anthrax, chicken cholera,
hydrophobia
❖Process of attenuation – live vaccines
❖Vaccine for rabies

26. GERM THEORY OF DISEASE BY LOUIS PASTEUR
Disapproves
spontaneous theory

27. STAINING TECHNIQUES

29. ROBERT KOCH-FATHER OF BACTERIOLOGY/
MEDICAL MICROBIOLOGY
❖1843–1910; Germany
❖Perfected bacteriological techniques
❖Studied anthrax bacillus
❖Staining techniques
❖Pure culture
❖Discovered
❖M.tuberculosis – 1882
❖V.cholerae – 1883

30. KOCH’S
POSTULATES

31. KOCH’S POSTULATES
Enunciated by Koch
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 the
lesion.
3. Inoculation of such pure culture into suitable laboratory animals should
reproduce the lesions of the disease.

32. KOCH’S POSTULATES
3. It should be possible to re-isolate the bacterium in pure culture from the
lesion produced in experimental animals.
4. An additional criterion: specific antibodies to the bacterium should be
demonstrable in the experimental animals.

33. DISCIPLES OF PASTEUR AND
KOCH
➢Hansen – Lepra bacillus – 1874
➢Neisser – Gonococcus – 1879
➢Ogston – Staphlyococcus – 1881
➢Loeffler – Diphtheria bacillus – 1884
➢Bruce – Malta fever – 1887
➢Roux, Yersin – Diphtheria toxin – 1888

34. IMPORTANT CONTRIBUTORS

35. IGNAZ SEMMELWEIS
▪1846; Vienna – puerperal sepsis
▪Mode of transmission
▪Prevention – hand washing in
antiseptic solution

36. JOSEPH LISTER
▪Antiseptic techniques in surgery
▪Carbolic acid

37. PAUL EHRLICH
❖Toxin and antitoxin

38. ALEXANDER FLEMING
▪Penicillium – destroys
Staphylococci
▪Florey & Chain – active
substance – mass production

39. FEW IMPORTANT CONTRIBUTIONS
▪Twort & d’Herelle – lytic phenomenon in bacterial cultures
▪Edward Jenner – vaccination
▪Von Behring & Kitasato – antibody
▪Bordet – humoral immunity
▪Metchnikoff – phagocytosis
▪Jerne – natural selection theory
▪Burnet – clonal selection theory

40. BIOTERRORISM

42. THANK YOU