15.1 - Antibiotics

Antibiotics

• A drug is any substance that, when taken into the body, changes or affects the chemical reactions happening inside it.
• Medicines are drugs used to treat disease - some just ease symptoms, while others attack the cause.
• An antibiotic is a medicine that cures a bacterial disease by either killing the bacteria inside the body or stopping them growing and dividing.

Why antibiotics don't harm your own cells

• Antibiotics interfere with processes that happen in bacterial cells but not in human cells - for example, building the bacterial cell wall, which human cells don't have.
• This is why they kill the bacteria without killing the body's own cells.

Where antibiotics come from

• Many are produced naturally by fungi and other microorganisms.
• Penicillin, the best-known antibiotic, is made by the mould Penicillium.
• Drug companies grow these organisms on a large scale and extract the antibiotic from them.
• Using antibiotics has greatly reduced the number of deaths from bacterial diseases.

Using antibiotics correctly

• A particular antibiotic only kills particular types of bacteria, so you must be treated with the right one for the infection.
• Finish the whole course, even once you feel better, so the infection is fully cleared and doesn't flare up again.
• Some bacteria are resistant to antibiotics, which makes antibiotics less effective against them and is a growing problem for treatment.

Antibiotics don't work on viruses

• Antibiotics have no effect on viruses, such as those causing flu and colds, because viruses are not cells and have none of the processes, such as building a cell wall, that antibiotics interfere with.
• Viruses reproduce inside the body's own cells, so it's very hard to make a drug that destroys the virus without damaging the cells it's hiding in.
• This makes antiviral drugs much harder to develop than antibiotics.