what are antimicrobials and how do they work?

the name ‘antimicrobial’ is an umbrella term for anything that inhibits or kills microbes including antibiotics (which target bacteria), antifungals (which target fungi) and antivirals (which target viruses).

what are antibiotics and how do they work?

any substance that inhibits the growth and replication of a bacterium or kills it outright can be called an antibiotic. antibiotics are a type of antimicrobial designed to target bacterial infections within (or on) the body.

antibiotics are used to treat bacterial infections. some are highly specialised and are only effective against certain bacteria. others, known as broad-spectrum antibiotics, attack a wide range of bacteria, including ones that are beneficial to us.

there are two main ways in which antibiotics target bacteria. they either prevent the reproduction of bacteria, or they kill the bacteria, for example by stopping the mechanism responsible for building their cell walls.

most antibiotics used today are produced in laboratories, but they are often based on compounds scientists have found in nature. some microbes, for example, produce substances specifically to kill other nearby bacteria in order to gain an advantage when competing for food, water or other limited resources.

antibiotics specifically target processes that are unique to bacteria, this means that they are relatively safe to use in the body. when used in low doses, antibiotics do not damage human or animal cells. importantly, this also means that antibiotics are not useful against other microorganisms such as fungi and viruses. 

what are other examples of antimicrobials?

both viruses and fungi grow in very different ways from bacteria and are composed of different materials. there are far fewer antiviral and antifungal drugs that have been approved for use.

antivirals

viruses require a live cell to replicate inside and they are very specific, meaning that each one will only replicate inside a certain type of cell and there are lots of different ways in which this happens. once inside the right cell, a virus is copied by the cellular machinery. this means that any drug that is developed to inhibit virus replication will be harmful to the cell’s own machinery, often making antiviral drugs more toxic than antibiotics. some antivirals are very cleverly designed to only be activated once inside an infected cell.

antifungals

antifungals have been developed to specifically interfere with targets that are unique to fungal processes, such as the fungal cell wall that is made of different components than bacterial cell walls.

antiparasitic drugs

parasites like the protozoa that cause malaria often have complex life cycles, with different stages of their development happening in different host types e.g. mosquitoes and human blood cells. different types of antiparasitic drugs have thus been established to target key stages of their development.