Antagonistic Index

Antagonistic index (AI) is a quantitative indicator of the antagonistic activity of microbes, which is expressed by the ratio of the number of colonies of microorganisms of two species after co-cultivation of a mixture of these microorganisms, composed in a certain ratio. This indicator is used to evaluate the antimicrobial activity of bacteria and determine their effectiveness in the fight against other microorganisms.

Antagonism is the ability of one organism to interfere with the development of another organism by releasing various metabolic products (antibiotics, enzymes, toxins, etc.). The antagonistic properties of microorganisms can be used in various fields, including medicine, agriculture and industrial production.

To determine the antagonistic index, it is necessary to co-cultivate two types of microorganisms in a certain proportion. The number of colonies of each species is then counted after incubation for a certain time. The ratio of the number of colonies of one species to the number of colonies of another species is the antagonistic index.

For example, if by co-cultivating a mixture of Escherichia coli and Bacillus subtilis in a ratio of 1:10, respectively, 100 and 1 colony of E. coli and 1 and 10 colonies of B. subtilis were obtained, then the antagonistic index will be equal to 10. This means that B .subtilis has a significant effect on E. coli, inhibiting its growth and development.

In addition, the antagonistic index can be used to determine the effectiveness of antimicrobial drugs. For example, if the AI ​​of a mixture of E. coli and an antibiotic is 0.5, then this means that the antibiotic is effective in inhibiting the growth of E. coli.

Thus, the antagonistic index is an important indicator of the antimicrobial activity of microorganisms and can be used to determine the effectiveness of various methods of controlling microorganisms in various fields.

The antagonistic index is a quantitative indicator that is used to assess the antagonistic potential of microbes. This indicator is expressed as the ratio of the number of colonies formed by two types of microbes after their co-cultivation.

Antagonism is the ability of one microorganism to suppress the growth of another. Antagonistic relationships between microbes can arise for various reasons. For example, some bacteria can secrete substances that inhibit the growth of other bacteria. Also, some microorganisms can produce antibiotics that kill other bacteria.

To determine the antagonistic index, it is necessary to co-cultivate two types of microbes in a certain proportion. The number of colonies formed of each species is then counted. The ratio of the number of colonies of the first type to the number of colonies of the second type is the antagonistic index.

A high antagonistic index indicates that one type of microbe has a high ability to inhibit the growth of other species. This may be useful in agriculture and medicine. For example, the antagonistic properties of some microbes can be used to combat other harmful microorganisms.

Also, the antagonistic potential of microbes can be used to create new antibiotics. If two types of microbes have an antagonistic interaction, then a substance can be isolated from them that will kill both types of microbes.

Thus, the antagonistic index is an important indicator for studying interactions between microorganisms and can be useful in various fields, including agriculture, medicine and biotechnology.