Answer:
1) Interrupting vital processes.
2) Horizontal or lateral gene transfer.
3) Misuse and overuse of antibiotics.
Explanation:
1) Antibiotics have different mechanisms of action, but they usually target bacteria vital processes such as protein or cell wall sysnthesis.
For example, tetracycline binds to the 30s and 50s subunits of the ribosome blocking the introduction of new amino acids to the peptide chain being synthetised. Without protein synthesis cells cannot divide, helping the immune system to kill them.
Penicillin inhibits the enzyme involved in the final step of cell wall biosynthesis interrupting bacteria cell division.
2) Bacteria have developed different strategies for the movement of material genetic other than the vertical transmission in mitosis.
Different mechanism of Horizontal Gene Transfer include transformation, conjugation and transduction. They use vectors like plasmids or bacteriophages (temperate virus) for the resistance genes transmission.
3) Individuals are taking antibiotics without prescription from certified health professionals; this leads to misuse of antibiotics.
Also health workers over-prescribe these medicines to treat mild diseases or viral infections. The overuse of antibiotics accelerates the spread of resistance.
We are not preventing infection from happening by not vaccinating, hand washing, assuring good food hygiene or practising safer sex.
All of this contribute to bacteria becoming resistant to commonly used antibiotics.