Question

there are 3 different ways bacteria can develop multi drug antibiotic resistance. explain how each method works.

Answer 1

Bacteria can develop resistance to a drug antibiotics by many different mechanisms. Some on them are

1. Modification of cell membrane

2.Mutation of target genes

3.horizontal gene transfer

1. Modification of members

The antibiotics act on the bacteria first encounter with cell wall. Cell wall is made-up of peptidoglycan and act as the protective barrier of the cell. Drug should pass thorough this cell wall or break the cell wall to penetrate the bacterial cell. If there modification of cell wall which makes it resistance for the entry of drug then the drug won't pass the cell and hence cannot damage the celll. Various environmental factors are responsible for modification of cell wall.

2. Mutation of target

Mutation means change is DNA sequence which can affect the Protein production in the bacterial cell. Physical and chemical mutagens cause mutation in cell. If the cell is mutated then there will be modification in the target due to the Target modification the drug won't bind the target and hence its activity will be neutralized. Mutation can also lead to protein production that destroys the antibiotics.

3. Horizontal gene transfer

HGT is method in which bacterial plasmid take up foreign DNA from environment or from other neighbouring bacteria. It contains 3methods - conjugation, transformation and transduction

In conjugation, F pilli is formed between 2 cells and gene is transferred from the pilli

In transformation, the naked DNA from the environment is incorporated in the cell

In transduction, the foreign DNA is incorporated by bacteriophage that attacks the bacteria. All this method in incorporat foreign gene or resistant gene in the bacterial sequence.

These are the main method that form resistance in bacteria.