This topic introduces Microbiology to Medical and Nursing students

1. INTRODUCTION TO MICROBIOLOGY
Definition
Micro – small, Bio – Life, Logy – Study
Microbiology is the study of living organism/micro organism (bacteria,
fungi, algae, protozoan and viruses) of microscopic size.
It is concerned with their morphology, structure, reproduction,
metabolism and classification.
History and evolution
- Lecretius (98 -55 BC) and Girolamo Fracastro (1478 - 1553) suggested
that a disease was caused by an invisible living creature.
- Robert Hooke (1635 - 1703) – Coined the word “cell”
- Matthias Schleiden and Theodor Schwann – Described the cell theory
(A cell is the basic structural and functional unit of an organism)

2. 1. The spontaneous generation (Abiogenesis)
Was stated by Aristotle in 346 BC, that living organisms could develop from non
living or decomposing matter.
Theory was supported by John Needham (1748)
- He boiled mutton broth and then tightly stoppered the flasks.
- Cloud was formed in the flask
- He concluded that the cloud was microorganisms
2. Biogenesis
Living organisms could develop from other
organisms.
A. Francesco Redi and the fly experiment (1629 - 1697)

3. B.Lazaro Spallanzani
(1729 - 1799): The heating
challenge
He opposed Needham’s
work.
C. Louis Pasteur (1822 - 1895)
His experiment ended the spontaneous generation.
The germ theory of disease: Bacteria are the
cause of disease in human, plant and animal.
The germ theory of fermentation:
Pasteurization ( heating milk at 62.8 0C for 30
min).

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Protection against infection (Immunity):
attenuated vaccines (older cultures of bacterium
are on virulent bacteriums of same disease e.g.,
Chicken cholera)
Principle of immunization
Pasteur applied this principle for
prevention of Anthrax
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5. D. Antony Van Leeuwenhoek
“Father of microscopy” The first person to observe and describe microorganisms.
E. Robert Koch (1843 - 1910)
Koch’s postulate: A specific microorganism can always found in association with a given disease
(Bacillus anthracis is a causative agent of Anthrax).
Staining: He discovered staining (Adding a dye to a microorganism to become visible).
F. Joseph Lister
He described Sepsis (surgical infections) using phenolic solution on wound to kills pathogens.
G. Alexander Flemmings
He is called as “father of antibiotics”. Penicillium notatum (Fungi) that produce antibiotic
Penicillin.
H. Fraun Hesse
Used agar as a solidifying agent
I. Richard J. Petri
Invented a petri plate
J. Edward Jenner
He described the concept of vaccination through a process called Variolation (An individual
affected by cow pox will not get small pox).