3. Microbiology
• Defined as the study of micro- organisms or microbes.
• Microbes are living organisms that are simple in structure, usually
small in size that are generally considered to be neither plants nor
animals
4.
5. Antonie Van Leeuwenhoek
• First scientist who observed bacteria
and other microorganisms
• Single lens microscope
• Little animalcules
6. • In ancient time people believed that living organisms could develop
from non-living matter.
• Many supported this theory
• Rudolf Virchow (1858) - concept of biogenesis - living cells can arise
only from preexisting cells
• It was Louis Pasteur who disproved this theory
Spontaneous Generation ( Abiogenesis)
7. Louis Pasteur (1822-1895)
• “Father of Microbiology”
• Proposed the principles of fermentation
• Introduced the sterilization techniques and
developed steam sterilizer, hot air oven and
autoclave
8. •Method of pasteurization of milk
• Vaccine development against several diseases, such as anthrax and
rabies
• Postulated the ‘germ theory of disease’- (disease cannot be caused by
bad air or vapor, rather it’s produced by the microorganisms present in air
• Liquid media concept: used nutrient broth to grow microorganisms
9. • Father of “antiseptic surgery / modern
surgery”
• Applied science of germ theory to surgery
• Observed postoperative infections were
greatly reduced by using disinfectants such
as diluted carbolic acid.
Joseph Lister (1867)
10. Robert Koch (1843-1910)
• Father of “Modern Microbiology”
• Proved that microorganism transmit the disease-
specific microorganism caused specific disease
11. Contributions:
• Introduced solid media for the culture of bacteria
• Methods for isolation of bacteria in pure culture
• Hanging drop method for testing motility
• Discovered anthrax bacilli, tubercle bacilli and cholera bacilli
• Introduced staining techniques by using aniline dye
12. Postulates:
• microorganism should be constantly associated with the lesion of the disease
• It should be possible to isolate the organism in pure culture from the lesions of
the disease
• Same disease must result when the isolated microorganism is inoculated into a
suitable laboratory animal
• Possible to re-isolate the organism in pure culture from the lesions produced in
the experimental animals
• Additional fifth criterion was introduced that antibody to the causative
organism should be seen in the patient’s serum
13. Exceptions to Koch’s postulates:
Mycobacterium leprae and treponema pallidum
Neisseria gonorrhoea
14. • Microorganisms are pathogens, one
pathogen– one disease
• Microorganisms need to be
eliminated
• solid medium for single colony
isolation is required to avoid
contamination
• Microorganisms are immutable that
could not be changed (The
Monomorphic hypothesis)
• Microorganisms are living things, some
are favorable, some are pathogenic
• Microorganisms need to be instructed
and can perform useful functions
(fermentation)
• Use of broth cultures with mixed
communities of microbes are
important to study
• Microorganisms are mutable and can
be modified. (The Pleomorphic
hypothesis of adaptation and
mutability)
15. Paul Ehrlich (1854-1953)
• Father of chemotherapy’
• He was the first to report the acid-fast nature of tubercle bacillus
• He developed techniques to stain tissues and blood cells
• He proposed a toxin-antitoxin interaction called Ehrlich phenomenon and also
introduced methods of standardising toxin and antitoxin
16. • proposed the ‘side chain theory for antibody production’
• discovered salvarsan, an arsenical compound (also called as the ‘magic
bullet’) as the first effective medicinal treatment for syphilis
• bacteria ‘Ehrlichia’ was named after him
