The development of new antibiotics is costly and slow. It is unlikely to…

The idea

Discovering and testing a new antibiotic takes many years and large amounts of money. Researchers must find a compound that kills bacteria without harming human cells, then test it in laboratories, animals and clinical trials to check safety, dosage and effectiveness. Many candidate drugs fail, so the cost of each successful antibiotic is very high. Meanwhile, bacteria reproduce rapidly and can acquire resistance through mutation or by transferring resistance genes, so resistant strains can appear quickly. This means the rate at which new resistant strains emerge can outpace the rate at which new antibiotics are developed.

For example: A resistant strain may spread through a hospital in months, while a new antibiotic may take more than a decade to reach patients.

What earns the marks

• Developing a new antibiotic requires many years of research, testing and clinical trials.
• The process is expensive because most candidate compounds fail and because trials must demonstrate safety and effectiveness.
• Bacteria reproduce rapidly and can mutate or acquire resistance genes, so resistant strains can emerge quickly.
• The slow rate of antibiotic development may not match the fast rate at which resistance appears.
• If new antibiotics cannot keep pace, some bacterial infections may become difficult or impossible to treat.
• Reducing unnecessary antibiotic use and developing new drugs are both needed to manage resistance.

Common mistakes and how to put them right

• Thinking that a new antibiotic can be created quickly once resistance appears.

  Put it right: Discovery, testing and trials take many years.

• Believing that resistance only develops after a new drug is widely used.

  Put it right: Resistance can emerge or spread rapidly once a drug is used.

• Assuming that cost is the only barrier.

  Put it right: Finding effective, safe compounds and completing trials are also major difficulties.

Exam tips

• Compare the timescale of antibiotic development with the timescale of bacterial reproduction and resistance emergence.
• Use specific stages such as laboratory testing, animal testing and clinical trials when explaining why development is slow.
• When asked to suggest a solution, link it to reducing selection pressure or to funding new drug development.