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Introduction toIntroduction toMicrobiologyMicrobiology

Department of Applied Science

King Saud University/ CommunityCollege

By: Murad Sawalha

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OutlineOutline

Other field of microbiology:Other field of microbiology:

- Paleomicrobiology.- Paleomicrobiology.

- Parasitology- Parasitology

- Sanitary microbiology- Sanitary microbiology

- Veterinary microbiology.- Veterinary microbiology.

Pioneers in the science of microbiology:Pioneers in the science of microbiology:

- Anton Van Leeuwenhoek (1632-1723)- Anton Van Leeuwenhoek (1632-1723)- Louis Pasteur (1822-1895)- Louis Pasteur (1822-1895)

- Robert Koch (1843-1910)- Robert Koch (1843-1910)

Metric systemMetric system

MicroscopesMicroscopes

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Pioneers in the science of microbiologyPioneers in the science of microbiology

1) Anton Van Leeuwenhoek (1632-1723)1) Anton Van Leeuwenhoek (1632-1723)

Invented the first microscope (50 300x), was the first to accuratelyobserve and describe microorganisms.

The first person who saw live bacteria & protozoa, for that he is referred to

as the father of microbiology, bacteriology, & protozoology. Was not a trained scientist.

He used his microscope to examine many specimens, he observed tinycreatures which he called animalcules.

Record his observations in letters, which convinced scientists of theexistance of microorganisms.

Depend on these findings, abiogenesis theory developed (the idea that lifecan arise spontaneously from non living material).

Following the works of Pasteur & Tyndall, this theory disproved, andproved that life can arise only from preexisting life (theory of biogenesis)

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Pioneers in the science ofPioneers in the science of

microbiologymicrobiology

2) Louis Pasteur (1822-1895)2) Louis Pasteur (1822-1895) Through his experiments, Pasteur dealt the fatal blow to the theory ofspontaneous generation (abiogenesis)

Developed vaccines for Chickenpox, anthrax, rabies

Demonstrated that all fermentations were due to the activities of specificyeasts and bacteria.

Developed Pasteurization to preserve wine during storage.

Pasteurization: can be used to kill pathogens in many types of liquids.

Discovered that fermentative microorganisms were anaerobic andcould live only in absence of oxygen.

He made significant contributions to the germ theory of disease (specificmicroorganisms cause specific infectious diseases), such as anthrax is

caused by a specific bacterium Bacillus anthracis, & tuberculosis iscaused by Mycobacterium tuberculosis

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Pioneers in the science ofPioneers in the science of

microbiologymicrobiology

3) Robert Koch (1843-1910)3) Robert Koch (1843-1910)

Proved that the anthrax bacillus is the cause of anthrax (contributein the germ theory)

He discovered that Bacillus anthracis produces spores, capable ofresisting adverse conditions.

He developed methods of fixing, staining, & photographingbacteria

He developed methods of cultivating bacteria on solid media- Petri dash: flat glass dish to culture bacteria on

solid media - Use of agar (a polysaccharideobtained from seaweed) as a solidifying agent.

- Pure culture: meansonly one type of organism is growing in a solid culture medium or

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Cont.Cont.

Kochs Postulates: scientific procedure to provethat a specific microorganism is the cause of aspecific infectious disease:

- Microorganism must be present in every case of thedisease but absent from healthy individuals

- The suspected microorganism must be isolated andgrown in pure cultures.

- The disease must result when the isolatedmicroorganism is inoculated into a healthy host.

- The same microorganism must be isolated from thedisease host.

Exceptions to Kochs postulates:

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Metric systemMetric system

Is used to describe the sizes ofIs used to describe the sizes ofmicroorganisms, the sizes of bacteria andmicroorganisms, the sizes of bacteria and

protozoa are expressed in micrometers,protozoa are expressed in micrometers,whereas the sizes of viruses are expressedwhereas the sizes of viruses are expressed

in nanometer.in nanometer.

A meter can be divided into 10A meter can be divided into 10

decimeters, 100 centimeters, 1000decimeters, 100 centimeters, 1000millimeters, 1 million micrometers, or 1millimeters, 1 million micrometers, or 1

billion nanometers.billion nanometers.