Science & Technology in Action

How antibiotics work
Antibiotics essentially work two ways:

Bactericidal antibiotics kill the bacteria generally by either interfering with the formation of the bacterium’s cell wall or its cell contents. Penicillin is one of these.

Bacteriostatic antibiotics stop bacteria from multiplying by interfering with bacterial protein production, DNA replication, or other aspects of their cellular metabolism, e.g. tetracyclines, sulphonamides

Some antibiotics are broad spectrum: these kill a whole range of bacteria both Gram positive and Gram negative; some of which are pathogenic. They may also kill the normal gut bacteria. Narrow spectrum antibiotics affect only a small range of bacteria.

When antibiotics were introduced they were hailed as miracle drugs. It seemed that the era of death from bacterial infections was over. In only a few short decades things have changed dramatically! 

Bacteria reproduce in such vast numbers that a random mutation can quickly result in a resistant strain. Antibiotic resistance ― more commonly known nowadays as antimicrobial resistance (AMR) ― is the ability of certain organisms to adapt and continue to multiply in the presence of an antibiotic. (The term ‘antimicrobial’ also includes drugs that act against viruses, fungi and protozoa, in addition to those acting against bacteria.’)

Resistant strains began to appear within a few years of the introduction of antibiotics, so new antibiotics had to be found to replace the ones to which resistance had developed. In the past 30 years only two new classes of antibiotics have appeared so the problem of antibiotic resistance is becoming more serious. 

The World Health Organisation has classified antimicrobial resistance as a “serious threat’ that ‘has the potential to affect anyone, of any age, in any country”.