Bacteria...?

How do bacteria create resistance to antibiotics and other chemicals? What happens really inside of them that makes them resistant?





Thanks a million!

Bacteria...?
Antibiotic resistance is a consequence of evolution by natural selection. Those bacteria which have a mutation allowing them to survive will live on to reproduce. They will then pass this trait to their offspring.





There are four main ways resistance manifests within the bacteria.


1. Drug inactivation or modification: e.g. enzymatic deactivation of Penicillin G in some penicillin-resistant bacteria through the production of Beta-lactamases.


2. Alteration of the binding target site of penicillins—in MRSA and other penicillin-resistant bacteria.


3. Alteration of metabolic pathway: e.g. some sulfa-resistant bacteria do not require para-aminobenzoic acid (PABA), an important precursor for the synthesis of folic acid and nucleic acids in bacteria inhibited by sulfonamides. Instead they utilize preformed folic acid.


4. Reduced drug accumulation: by decreasing drug’s ability to pass through the cell’s surface.








The bacteria’s DNA changes and allows them to survive. Sometimes these traits happen in plasmids which are little pieces of DNA that are outside the nucleus. Plasmids can also pass from one cell to another without reproduction or cell division.
Reply:a byproduct of some unrelated biochemical process that you're carrying out naturally-you don't want to be killed by that. So you have a resistance mechasim built in. And somehow, that resistance gene or genes came out of you and moved to another bacterium that isn't making the antibiotic, but now resists the antibiotic.





Because these genes are transferable, and they eventually got transferred to other bacteria. In the process, mutations could occur, adaptations could occur. But the basic mechanism, in fact we find in many of the producing organsims.





The Darwinian idea is that if they make that change and it helps them, then that change becomes more permanent. So a mutation to a gene that results in a resistance to an antibiotic like pennicillin in certain bacteria could be a mutation in the target. And those bacteria survive, and their progeny now carry that mutation.





might have never made it in normal times-now, if they give the bacterium the ability to resist an antibiotic, they are there and they are there to stay.
Reply:it happens when bacteria sensitive to any type of antiobitic grow in an isotonic medium.