Answer:
1) Permeability of cell membrane,
2) changing in target site of antibiotics caused by DNA mutations
Step-by-step explanation:
Resistant bacteria are genetically modify themselves by DNA mutations. These mutation alters the normal pathway function of bacteria and change their role against the antibiotics which we take in. These modified bacteria will show rigid permeability and does not allow the antibiotics to penetrate inside. Being mutated these bacteria produce enzymes which have capability to degrade the enzymes of antibiotics, this alters the appropriate recognition of target site (drug receptors). Thus, the normal metabolic pathway is disturbed and these bacteria becomes resistant to antibiotics.
Difference in response to an antibiotic found in the environment:
Staphylococcus aureus can be quoted as a best example as it has become resistant to antibiotics. It is the most common bacteria that exists in upper part of our respiratory tracks. But now S. aures has become resistant to methicillin (antibiotic) by using genetical modifications. Now, advanced alternative antibiotic drug has to be designed to act against Staphylococcus aureus.