1) The document discusses the history and evolution of microbiology from its early pioneers like Leeuwenhoek and Pasteur to modern classification. 2) It highlights key discoveries such as Leeuwenhoek first observing microorganisms under a microscope. Pasteur later debunked spontaneous generation and established germ theory of disease. 3) Koch further advanced the field with techniques like staining and culturing bacteria, and formulated Koch's postulates for linking microbes to disease. This helped establish microbiology as a science.

1. BABCOCK UNIVERSITY
COURSE CODE: MLSC 201
LECTURE TOPIC: HISTORY AND EVOLUTION OF
MICROBIOLOGY

2. • Lecture Objectives
• At the end of the lecture, the student should
be able to:
Define medical microbiology
Name 4 pioneers of science of microbiology
List the landmark discoveries in the evolution
of microbiology

3. • WHAT IS MICROBIOLOGY?
• The study of microorganisms and their activities:
Nutrition, multiplication, pathogenicity, control, etc.
• WHAT ARE MICROORGANISMS?
• They are very minute organisms that are too small to
be seen with the naked eye. They are also referred
to as microbes.
• They are observed with the of a magnifying device
called the microscope.

4. • WHAT IS MEDICAL MICROBIOLOGY
• The study of disease causing microorganisms
with respect to man.
• Disease caused by a microorganism is called
“infectious disease” or simply, “infection”.
• Differentiate disease from infection!!
• The more we know of microorganisms, the more
the quality of human life is improved.

5. • EVOLUTION AND HISTORY OF MICROBIOLOGY
• The science and evolution of microbiology is an
interesting chronicle of man’s indomitable spirit
to conquer.
• The history is loaded with landmark
breakthroughs of early scientists that has made
microbiology as one of the most applied
sciences.

6. • Brief History
• Prior to the discovery of microorganisms, there
were two kingdoms of living things: Plant and
animal.
• 1675: Anthony van Leeuwoenhoek, a Dutch
draper, described the “little animals”
(animacules) he observed with his crude home
made microscope while examining rain water and
watery infusions.
• He was the first man to describe microorganisms.

7. • Controversy similar to one concerning the
origin of life was witnessed in the case of the
origin of microorganisms.
• The theory or concept of “spontaneous
generation” was put forward and believed by
many scientists for centuries.
• They believed that life arose spontaneously
from pre-existing life and so the term
“abiogenesis”.

8. • Meanwhile, there were opponents of this idea.
The controversy was on for over 100 years.
• In 1868, an Italian scientist, Francesco Redi,
after many smart experiments, disproved the
theory of abiogenesis.
• Louis Pasteur (1822-1895), a French chemist (
the father of modern medicine), performed
series of brilliant researches and experiments for
the wine industry between1860 and1890.

9. • Through his several experiments in the wine
industry, was able to debunk the spontaneous
generation hypothesis. He described vaccine and
vaccination to protect against microbial activity.
• He developed methods of culture and showed that
microorganisms cause disease. With other scientists,
he formulated the “germ theory of disease”.
• He established the principles of immunisation.
• He collaborated with John Tyndall (1820-1883) a
physicist, to convince others about fallacy of
abiogenesis and proof of biogenesis.

10. • Joseph Lister, Professor of surgery in Glasgow,
applied Pasteur’s observations to the prevention
of wound sepsis.
• In 1867, he discovered the use antiseptic
technique to kill bacteria in wound and air with
carbolic acid.
• Robert Koch (1843-1910) (father of medical
microbiology), a German scientist, discovered
that bacteria caused diseases such as
tuberculosis, anthrax etc.

11. • Most of his work was between 1876 and 1884. He
discovered the anthrax bacillus in 1876 ahead of
Pasteur and two of them had become rivals.
• With his assistant, Ehrlich (who worked on dyes),
they were able to stain bacteria and viewed them
on the microscope.
• He introduced agar as gelling agent for culture
media. He was the pioneer in laboratory technique.
• He enunciated the famous Koch’s postulates:

12. • 1. The organism must be found in every case of the
disease.
• 2. The organism must not be found in a healthy
person.
• 3. The organism must be isolated and grown in pure
culture.
• 4. Inoculation into a susceptible animal should
reproduce the disease and the organism isolated
from the animal.
• 5. Infection should produce circulating antibody
specific for the infecting organism.

13. • It is obvious now with current knowledge that all
the postulates are not applicable in every disease
condition.
• CONFUSION:
• In-spite of the tremendous progress made, there
was still confusion.
• Living things then belonged to Animal kingdom or
Plant kingdom
• In which kingdom did these microorganisms
belong?

14. • 1866: Hackel proposed the creation of a third
kingdom – the Protista
• Protista included: algae, protozoa, fungi,
bacteria and viruses.
• 1957: Stanier divided Protista into Eukaryotic
(higher) cells and Prokaryotic (lower) cells.
• To minimise the confusion, microbiology was
broken into Bacteriology, Virology,
Parasitology and Mycology.