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Antimicrobial Resistance

How antibiotic resistance emerges


Laura JV Piddock

Professor of Microbiology and Deputy Director of the Institute of Microbiology & Infection, University of Birmingham


Victoria Wells

Science Communications Officer, British Society for Antimicrobial Chemotherapy Birmingham

Bacteria that are resistant to antibiotic drugs develop through the natural process of evolution, where microbes undergo changes that help them survive in hostile environments, such as exposure to antibiotics.

Bacteria grow and reproduce quickly, doubling their numbers every 20 minutes. At first, a few bacteria may be drug-resistant, but in the presence of antibiotics, all the susceptible bacteria die, and the resistant bacteria grow. These can reach huge numbers within one day. This happens in any environment, whether it be a person, an animal, soil, plants, oceans or our homes. Anywhere that antibiotics are used, drug-resistant bacteria occur. It is therefore vital that we only use antibiotics when necessary. This is why people are encouraged not to ask their doctors for antibiotics for coughs and colds. Doctors have also been urged to only prescribe antibiotics for bacterial infections – this is called good stewardship. Quickly diagnosing the cause of most infections is difficult, but as some can be very serious, doctors urgently need new tests to help them decide when to use antibiotics. The Longitude Prize will be awarded for a new test that can do this anywhere in the world.

Reducing the number of drug-resistant bacteria is difficult. Resistant bacteria are just as likely to cause infections as susceptible bacteria, and sometimes they transfer their resistance to other microbes. It is therefore essential that we prevent the spread of infection between people, animals, and the environment. This is why it is so important for people and animals to have clean water and good public health systems including closed sewers. 

There are many different types of drug-resistant bacterial infections throughout the world, they are easily transmitted and there are few effective new drugs.  All non-essential use of these life-saving drugs must be stopped so that they remain effective for as long as possible.

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