Role of Antibiosis and Immunization in Controlling Bacterial Disease

Discuss the role of antibiosis and immunization in controlling bacterial disease?

CHEMICAL METHODS:

Chemical methods for control of bacterial include antiseptics, disinfectants and chemotherapeutic agents controlling bacterial diseases.

(1) Antiseptics:

These are chemical substances used on living tissues to kill and inhibit the growth of microorganisms.

(2) Disinfectants:

These chemical agents are used to inhibit the growth of vegetative cells on the non-living materials.

These include oxidizing and reducing agents. For example halogens, phenols, hydrogen peroxide, Potassium permagnate, alcohol and formaldehyde etc.

(3) Chemotherapeutic:

Chemotherapeutic agents and antibiotics work with natural defense and stop the growth of bacteria and other microbes. They destroy or inhibit the growth of microorganisms in living tissues.

These are Sulfonamides, tetracycline, penicilin, etc.

Some other processes that kill/inhibit the microbial population are:

(i) Microbicidal Effect:

Microbicidal effect is one that kills the microbes immediately.

(ii) Microbistatic:

Microbistatic inhibits the reproductive capacities of the cells and maintain the microbial population at constant size.

Mode of Action:

Mode of action, of different physical and chemical agents, of control vary.

Damage can result malfunctions in cell wall, cell membranes, cytoplasm, enzymes, or nuclei acid.

IMMUNIZATION AND VACCINATION:

To control and prevent microbial diseases following methods are used:

(i) Immunization (e.g. vaccination)

(ii) Antisepsis (used to eliminate or reduce infection)

(iii) Chemotherapy and

(iv) Public health measures (e.g. water purification, sewage disposal and food preservation)

Pasteur made many discoveries about the cause and prevention of infectious diseases. His work is very important in developing immunity by vaccines.

Pasteur's Work on Chicken Cholera:

In 1880's he isolated the bacterium that caused chicken cholera. He grew it in a pure culture.

To isolate the bacterium of this disease, Pasteur used the techniques of Koch. He also demonstrated this publically.

Experiment:
He inoculated healthy chicken with this pure cultures.

He waited for many days but chicken cholera did not develop in the chicken.

Error in his experiment:

Pasteur found that he had used the cultures several weeks old instead of fresh one.

Discovery:

He discovered that somehow bacteria had lost their ability to produce the disease (virulence) after standing and growing old.

These less virulent bacteria, could still stimulate the host (in this case the chicken) to produce antibodies.

Antibodies are substances that protect the host against infection from virulent organism.

(i) Pasteur's Work on Anthrax:

Pasteur applied the above mentioned principle for the prevention of anthrax.

This culture of the less virulent germs was called vaccine (in Latin vacca means cow).

Similarly immunization with less virulent germs was called vaccination.

(ii) Pasteur's Work on Rabies:

Then Pasteur also developed a vaccine for hydrophobia, or rabies.

It is a disease transmitted to people by bites from rabid dogs, cats, and other animals.

(iii) Pasteur Honouring Edward Jenner:

Pasteur honoured Edward Jenner (1749 - 1823).

Jenner successfully vaccinated a boy against small pox in 1796.

He observed that milkmaids who contracted cowpox from the cows, never developed small pox.

He tested his hypothesis by inoculating a bot (James Phipps) first with cowpox causing material and later with small pox causing material. The boy did not get small pox.