chap 1 Fy Year Bsc Nursing

1. Introduction ToMicrobiology
-KHYATI CHAUDHARI

2. introduction
Medical microbiology is the study of microbes that infect humans, the
diseases they cause, their diagnosis, prevention, and treatment. It also deals
with how the human body handles the invading microbes.
Disease & death have always fascinated humans. In early times, people
believed that disease was caused by supernatural forces and divine wrath. Later,
it was believed that the environment, bodily constitution(i.e. weight & height) &
diet contributed to disease.
Varo & Columella suggested that diseases were caused by inhaled or
ingested invisible beings. von Plenciz(1762) suggested that each disease was
caused by a separate agent.

3. introduction
As microbes are not visible to the unaided eye, knowledge about them
had to await the development of microscopes. Microbes were first observed in
1675 by Antonie van Leeuwenhoek. In Holland, whose hobby was grinding
glass to make lenses & observing diverse materials through them.
In 1683, his accurate descriptions of little animalcules were presented to
the Royal society of London, but the significance of these observations was not
realized at the time. Ignaz Semmelweise (1846) in Vienna had independently
concluded that puerperal sepsis was caused by introduction of an infectious
agent. He found that this agent was transmitted by medical students attending
to women in labour after working on cadavers in the anatomy department.

4. Antonie van Leeuwenhoek
Fatherof Microbiology

5. introduction
However, women attended by nursing students in the labour room did not
develop puerperal sepsis, as the nurses had washed their hands before
assisting the women. To prevent puerperal sepsis, Semmelweise introduced
hand washing using an antiseptic solution, which reduced the number of
women affected. However, there came a time when his thoughts and ideas,
though true and relevant, were not accepted.

6. Microbiology
Microbiology is the study of all the organisms that are too small to be seen with
the naked eye (<0.1mm).

7. WhyStudyMicrobiology?
 Impact on human life
 Decomposers
 Microbes are ubiquitous: soil, water, ice cap, hot vents, body
 Simple models to study biological processes

8. PositiveImpactonHumanLife
 Microbiome
 Food source
 Antibiotics and other chemicals
 Bioengineering
 Decomposers
 Ecological balance
 Biodegradation
 Bioremediation

9. NegativeImpactonHumanLife
 Pathogens (disease causing agents)
 Food spoilage
 Corrosion
 Bad smells

10. LouisPasteur(1822-1895)
Louis Pasteur was a French scientist
who proved that all forms of life arose
from their like & not spontaneously ,
thereby defining the Germ theory, &
disproving the dogma of spontaneous
generation.

11. LouisPasteur
His studies on fermentation of wine established that Fermentation was the
result of microbial activity.
 He developed the method of Pasteurization to prevent spoilage of food by
bacteria.
 He introduced techniques of sterilization & developed the steam sterilizer,
hot air oven & autoclave.
 He also established the differing growth needs of bacteria & studied the
causes of anthrax, chicken cholera and rabies.

12. LouisPasteur
CHICKEN CHOLERA ANTHRAX

13. LouisPasteur
RABIES

14. LouisPasteur
An accidental observation was made by Pasteur that chicken cholera bacillus
culture left on the for several weeks lost their ability to cause disease, but could
still protect birds against subsequent infection. This is process of attenuation &
its discovery led to the development of live, attenuation vaccines. (1881)
 Once of Pasteur’s greatest contributions was the development of a vaccine
for rabies. For his many contribution to the field of microbiology, he is known as
Father of Modern Microbiology.

15. EdwardJenner(1749-1823)
Edward Jenner was an English
physician & scientist.
During these smallpox outbreaks in
1788, he observed that milkmaids
who had suffered from cowpox
infection never came down with
smallpox even though they were
exposed to infected people.

16. EdwardJenner
In 1796, he conducted an experiment on an 8 year old boy.
He inoculated a small amount of exudate from a lesion of a patient with
cowpox.
A few weeks later, when Jenner repeated the injection using fluid from a
smallpox vesicle, the boy remained healthy.
In this way, he introduced the techniques of vaccination, where a similar but
attenuated organism is given to individuals & coined the word vaccination. ( from
Latin vacca meaning cow.)

17. Josephlister(1827-1912)
 Sir Joseph Lister was a
British surgeon and a pioneer
of antiseptic surgery.
He suggested that microbes caused
surgical wound infections which could
be prevented by antisepsis.
Lister promoted the idea
of sterile surgery while working at
the Glasgow Royal Infirmary. Lister
successfully introduced carbolic acid
(now known as phenol)
to sterilize surgical instruments and to
clean wounds.

18. Josephlister
This resulted in a significant reduction in the numbers of infections and deaths.
He also experimented with hand washing, sterilizing materials before surgery
& spraying the operation theatre with carbolic acid.
He known as Father of Antiseptic Surgery.

19. RobertKoch(1843-1910)
Heinrich Hermann Robert Koch was a
German physician and microbiologist.
He perfected bacteriological techniques
during his studies on the culture & life
cycle of the anthrax bacillus.
He introduced staining techniques,
methods of obtaining bacteria in pure
culture using solid media & discovered the
tuberculosis bacillus (1882) & the cholera
virus (1883).

20. RobertKoch
As the causative agent of various infectious diseases were being reported by
different investigators, it became necessary to introduce tests to prove that the
microorganisms isolated from a disease was indeed the causative agent.
These criteria laid down by Koch, are known as Koch’s postulates.
He is known as Father of Bacteriology.

21. Koch’spostulates
Microorganism can be accepted as the causative agent of an infectious
disease only if following conditions are fulfilled:
1. Disease agent must be present in every organism suffering from the disease
but should be absent in healthy organism.
2. It should be possible to isolate the microorganism in its pure culture from
lesion of the disease
3. The isolated microorganism when introduced into suitable laboratory animal
should produce the similar disease.
4. It should be possible to re-isolate the microorganism in its pure culture from
lesions produced in experimental animals.

22. Koch’spostulates
•An additional rule introduced later requires that specific antibodies to microbe
should be demonstrated in the serum of patients suffering from the disease.
•In case of an organism that cannot be grown in culture, molecular methods can
be used for identification of the pathogen.
•It may not always be possible to satisfy all the postulates in every case & there
are exceptions.

23. Paulehrilich(1854-1915)
Paul Ehrilich was a Nobel prize-
winning German-Jewish physician &
scientist who worked in the fields
of hematology, immunology,
and antimicrobial chemotherapy.
He known Father of Chemotherapy.
In the early twentieth century,
attempts were made to prevent
infectious disease by developing
vaccines & sera.

24. Paulehrilich
He known for his early pioneering work in the field of immunology &
antimicrobial therapy.
He discovered Salvarsan to treat syphilis & also developed a method to stain
the tubercle bacilli, the causative agent of tuberculosis.

25. AlexanderFleming(1881-1955)
Sir Alexander Fleming was a
Scottish biologist, physician, microbiol
ogist, and pharmacologist.
He discovered first antibiotic.
He Accidentally discovered Penicillin
produced by a fungus Penicillium.
He left his Staphylococcus culture on
an agar plate for 2 weeks & went on
vacation.
When came back & found mold on
his plate which prevented bacterial
growth.

27. AlexanderFleming
Further work on this finding at Oxford by Florey, Chain & their team during
Second World War led to the production of the drug penicillin.
This was the beginning of the antibiotic era & other antibiotics were discovered
in rapid succession.
With the increasing number of antibiotics came the increasing resistance to
them by bacteria.
Global eradication & control programs for various diseases were started &
smallpox was finally eradicated worldwide in 1977.
However, at the same time, newer diseases began to appear; e.g. AIDS was
first identified in 1981.

28. Principles&practicesofmedicalmicrobiology
The nature & behaviour of microorganisms.
Principles of growth & reproduction of microorganisms.
Identifications of microorganisms using staining, pure culture, bio-chemicals &
antigenic techniques.
Study of epidemiology, clinical features, laboratory diagnosis & control
measures for microbial diseases caused by bacteria, viruses, fungi & parasites.