Antimicrobial resistance (AMR) refers to the ability of a microorganism to grow in the presence of drug or a chemical that would normally limit its growth or kill it.
It makes it difficult for the existing drugs to eliminate the infection as they become less effective against the microbe.
There are five major mechanisms by which a microbe attains resistance against antimicrobial chemical or drug:
Drug modification or inactivation: A microbial enzyme inactivates the antimicrobial agent. For example, few bacteria produce β-lactamases which provide multi-resistance against β-lactam antibiotics such as penicillin, cephalosporin etc.
Alteration or modification of target site: An altered target site prevents the antimicrobial agent from binding to its target. For example, alteration of penicillin binding protein (PBP) in Methicillin-resistant <em>Staphylococcus aureus </em>(MRSA).
Alteration of metabolic pathway: The microbe uses an alternative pathway to circumvent the blocked pathway. For example, sulfonamides-resistant bacteria started using preformed folic acid in place of para-aminobenzoic acid (PABA).
Decreased drug accumulation: Microbial efflux pumps remove the antimicrobial agent (before it could do any damage) by pumping it out of the cell.
Decrease in cell permeability: The permeability of the microbial envelope to the antimicrobial agent is decreased
The plasma membrane has a double layer of phospholipids with proteins dispersed throughout. These proteins help increase the durability of the membrane, as well as help with filtration.
Wind has some advantages which makes it suitable as a source of energy but it also possesses some disadvantages which reduces its potentials as a viable source of energy. For instance, large expanse of land will be needed to construct wind farms and this may not be feasible especially in populated areas. Another disadvantage is that electricity production will be depended on the availability of wind, when there is no wind, there will be no electricity.
There are two kinds of food chains one starting with autotrophs, the grazing food chain, and the other starting with dead organic matter, the detrital food chain.
