Microbiology is the study of organisms that are usually too small to be seen by the unaided eye; it employs techniques—such as sterilization and the use of culture media—that are required to isolate and grow these microorganisms.

1. History and Scope of
Microbiology
Md. Saiful Islam
BPharm, MPharm (PCP)
North South University
Fb Group: Pharmacy Universe

2. 2
Microbiology- Defination
• Microbiology – study of
microorganisms (simple forms of
life visible only through a
microscope usually single celled)
• Found everywhere
• Cause infections
– Mild
– Severe

3. History
• Microbiology began when people learned to grind lenses from
pieces of glass and combine them to produce magnifications
great enough to enable microbes to be seen.
• During the 13th century, Roger Bacon postulated that disease is
produced by invisible living creatures.
• In 1658, Athanasius Kircher referred to “ worms” invinsible to
the naked eye in decaying bodies, meat , milk and diarrhoeal
secretions.
Although his description lacked accuracy, he was the first
person to recognize the significance of bacteria and other
microbes in disease.

4. History-The beginning
• 1665 Robert Hooke observed living plant tissues
(20X mag.)
• “Little boxes” or Cells
• Used simple magnifying lens
• Suggested all living things are made of cells
• Perhaps his most famous microscopical observation
was his study of thin slices of cork. He wrote:
– . . . I could exceedingly plainly perceive it to be all
perforated and porous. . . these pores, or cells, . . . were
indeed the first microscopical pores I ever saw, and
perhaps, that were ever seen, for I had not met with any
Writer or Person, that had made any mention of them
before this

5. Hooke's Microscope
1665
Antonie van Leeuwenhoek was
inspired by this publication

6. Antonie van Leeuwenhoek
(1677) (“layu-wen-hook”)
• Pioneer microbiologist, was born in Delft, Holland and
learned the art of making lenses in Amsterdam. On his
return to Delft in 1652, he developed an interest in
microscopy. He announced the discovery of protozoa in
1677 in the Philosophical Transactions. He was the first
to distinguish bacteria and he published his drawings in
the same journal in 1683. He is esteemed as the first
protozoologist and bacteriologist. He also observed
canals in bone in 1675,later called the Haversian canals.
Following his death, his 248 microscopes were auctioned
by his daughter Maria" (A Dictionary of the History of
Medicine, Anton Sebastian).

8. • His descriptions of protozoa were so accurate that
many of the forms he described are easily recognized
today.
• The lenses of Leeuwenhoek’s microscope were well
made and he had the openness of mind that is so very
important in an investigator.
• He carefully recorded his observations in a series of
letters to the British Royal Society and in one of his
letters (dated Sept 7,1964) , he described the “ very
little animalcules” which we recognize as free-living
protozoa.

9. OLD MINDSET
Before the time of Pasteur, microorganisms were
studied mainly to satisfy curosity concerning their
characteristics and their relationships to higher living
forms, without awareness of their importance in
fermentation and disease.

10. The Golden Age of Microbiology!
•Louis Pasteur (finally disproved spontaneous generation
after many years of debate)
– Boiled broth in long-s-shaped necked flasks (unsealed)
• Remained sterile
• Proved that microorganisms are present in air, but air
does not create microbes
– Beginning of the golden age of microbiology

11. Swan neck flask experiment disproved spontaneous generation(1861)

12. Luis Pasteur

13. Pasteur—Father of microbiology
•1857- Louis Pasteur saves France’s wine industry
•Napoleon III begged Pasteur (a chemist by training) to help
solve a problem
•Sailors were mutinying because their wine was spoiling
after only a few weeks at sea
•Pasteur armed with his trusty microscope accepted the
challenge

14. 1857-Louis Pasteur saves France’s wine
• Good wine contained yeast
• Sour wine contained bacterium (Bacteria that use alcohol
and produce acetic acid spoil wine by turning it to
vinegar (acetic acid).
• He reasoned that if wine is heated to destroy the harmful
bacteria it wouldn’t spoil (process known as
Pasteurization)

15. FERMENTATION
• He found that fermentation of fruits and grains, resulting in
alcohol, was brought about by microbes.
• By examining many batches of ‘ferment’, he found microbes of
different sorts. In good lots one type predominated and in the
poor products, another kind was present.
• By proper selection of microbe, the manufacturer might be
assured of a consistently good and uniform product.
• He suggested that the undesirable types of microbes might be
removed by heating-not enough to hurt the flavor of the fruit
juice, but enough to destroy a very high percentage of microbial
population.
• He found that holding the juices at a temperature of 62.8°C for
30 mins did the job.
• Today pasteurization is widely used in fermentation industries,
but we are most familiar with it in the dairy industry.

17. The Germ Theory of Disease
• Even before his hypothesis in 1857 that microorganisms
are responsible for infectious diseases, many scientists
had expressed strong comments.
• Fracastro of Verona suggested that diseases might be
due to invisible organisms transmitted from one person
to another.
• In 1762 von Plenciz not only stated that living agents
are the cause of disease but suspected that different
germs were responsible for different diseases.
• In 1842 Oliver Wendell Holmes stated that puerperal
fever, a disease of childbirth, was probably caused by a
germ from one mother to another by midwives and
physicians.

18. The Germ Theory of Disease
• Pasteur’s success in solving the problem of
fermentation led the French government to request
that he investigate pebrine, a silkworm disease that was
ruining an important French industry.
• For several years, Pasteur struggled with the problems.
Finally he isolated the parasite causing the disease.
• Turning from silk to wool, Pasteur next handled the
problem of anthrax, a disease of cattle, sheep and
sometimes, human beings.
• He grew the microbes in laboratory flasks after isolating
them from the blood of the animals that had died of the
disease.

19. Robert Koch (1843-1910)
• German country physician who developed microbiology
into a science
• He was busy with the anthrax disease in Germany.
• He first discovered the typical bacilli with squarish ends in
the blood of cattle that had died of anthrax.
• He grew these bacteria in cultures in his laboratory,
examined them microscopically to be sure he had only one
kind present and then injected them into other animals to
see if these became infected and developed clinical
symptoms of anthrax.

20. Bacillus anthracis
From these experimentally infected
animals, he isolated microbes
similar to those of sheep that died
of anthrax. This was the first time a
bacterium had been proven to be
the cause of animal disease.

21. Koch’s Postulates
This series of observations led to the establishment of Koch’s
postulates, which provided guidelines to identify the causative
agent of an infectious disease.
1. A specific organism can always be found in association
with a given disease.
2. The organism can be isolated and grown in pure
culture in the laboratory.
3. The pure culture will produce the disease when
inoculated into a susceptible animal.
4. It is possible to recover the organism in pure culture
from the experimentally infected animal.

22. Koch’s findings
Koch and his coworkers discovered that bacteria caused-
•TUBERCULOSIS
•CHOLERA
•DIPTHERIA
•TYPHOID FEVER
•GONORRHEA
•PNEUMONIA

23. Honors
The success of Pasteur and Koch brought honors and
accolades from their appreciative countrymen.
1. Koch became Professor of Hygiene and Director of
the Institute for Infective Diseases, which was found
for him at the University of Berlin.
2. France showed its gratitude by establishing the
Pasteur Institute in Paris in 1888.

24. Founders of Microbiology (Review)
•First observed microbes—
Leeuwenhoek
•Proved living cells can arise only from
other living cells---Pasteur
•Confirmed the Germ Theory of Disease
--Koch

25. Scope of microbiology

26. • Medical importance
– Gastroenteritis
– Syphilis
– Tetanus
– Lyme disease
– Plague
• Pharmaceutical importance
– Antibiotics
• polymyxin
– Hormones
• Insulin
• Industrial importance
– Food supplements
• Amino acids & Vitamins
– Organic solvents
• Acetone
Environmental importance
* Biodegradation
- Oil spills
- Wastewater treatment

27. Biotechnology and Recombinant DNA
• Biotechnology:
– The use of microorganisms, cells, or cell components to
make a product
– Foods, antibiotics, vitamins, enzymes
• Recombinant DNA Technology:
– Insertion or modification of genes to produce desired
proteins

28. Why Do We Study Microorganisms?
• We study microbiology because bacteria, viruses
and fungi are the leading cause of death in the
history of mankind.
• Bacteria, viruses and fungi have been responsible
for the downfall of governments, famine, and death
on an almost incalculable scale.
• It has only been in the last one hundred years that
we have finally begun to win the age old battle with
these small and deadly bugs.

29. Why Do We Study Microorganisms?
• Some Microorganisms Benefit Man:
- Many microorganisms are involved in the
production of food or are directly edible.
- The presence of bacteria (normal flora) in our
bodies inhibits the growth of potentially
pathogenic bacteria helping to keep us healthy.

30. Why Do We Study Microorganisms?
• Some Microorganisms Benefit Man:
- Modern biotechnology is often associated with the use of
genetically altered microorganisms such as E. coli or yeast for
the production of substances like synthetic insulin or
antibiotics.
- Biotechnological advances in agriculture also require the
help of microorganisms to form Transgenic Plant with
increased yield, reduced vulnerability to environmental and
pathogenic stresses, and improved taste.

31. Applied Microbiology and Biotechnology
• Practical applications of microorganisms in
manufacturing products or carrying out particular
decomposition processes is called biotechnology.
• Many use fermentation.
– food science
– industry
– medicine
– agriculture
– environmental protection

32. Microorganisms and Food
Microbes and humans compete for nutrients in food.
Microbes, through fermentation, can impart desirable
aroma, flavor, or texture to foods.
• Bread – yeast leaven dough by giving off CO2
• Beer – fermentation of wort
• Wine –fermentation of fruit juices
• Vegetable products –pickles, and soybean derivatives
• Vinegar –fermentation of plant juices
• Milk and diary products – cheeses, yogurt

33. How Microorganisms Cause Disease
By using up nutrients or other
materials needed by cells and
tissues they invade.
By damaging body cells by
reproducing inside the cells
By making body cells targets
of body’s own defenses
Resulting in:
Fever
Tiredness
Aches
Weakness
Skin reactions
Gastrointestinal
upset
Transmitted from one person to another by direct touching
or by vectors, droplets, or contaminated food or drink.

34. Microorganisms Type
Types of microorganisms:
• Viruses
• Bacteria
• Protozoans
• Fungi
• Multicellular parasites
• Named by first word refers to genus (biologic
classification between family and species) and
second word refers to particular species
Staphylococcus aureus