Scientists have discovered new bacteria which resist the most powerful antibiotics. Doctors fear that unless scientists find new ways to fight these superbugs, it is only a matter of time before a new strain of killer bacteria appears that cannot be controlled.

Bacteria are the dominant form of life on Earth. There are more of them than any other creature. This is because they are able to multiply rapidly. They can change to avoid a threat before it can defeat them.

A single bacterium can produce billions of descendants a day. If just one bacterium resists an antibiotic then it will multiply, and all its descendants will be resistant to the drug. They have been doing this for a long time. Bacteria which were resistant to penicillin, the first antibiotic drug, were found very soon after its introduction in the 1940s.

So far doctors and scientists have always been able to develop new types of antibiotics that can defeat the new strains. But new bacteria have been discovered that can resist even the most powerful antibiotics. Scientists are investigating other ways they can resist these superbugs.

One method is very simple: to make sure doctors use antibiotics less often. This will not prevent new superbugs from developing, but it will slow down the process. In Europe and the USA it is thought that antibiotics are prescribed unnecessarily in a third of all cases.

Sometimes it is the patients' fault. They demand antibiotics to treat all illnesses, even those caused by viruses. Antibiotics do not work against viruses.

Another method is to use creams instead of pills. Applying an antibiotic cream just to the area of infection is better than taking a pill that kills all the bacteria in your body. There is less chance of resistant bacteria developing.

Another answer is an old idea that was abandoned after the power of penicillin was discovered. It uses bacteria's natural enemies - viruses known as bacteriophages. These ‘bug-eating bugs’ enter the bacterium and kill them. They are more effective than antibiotics in some animal studies.

Scientists in the former Soviet Republic of Georgia and Britain are looking at how to use them to treat infected humans. But even bacteriophages have to be matched to exact types of bacteria.

The race is on for scientists to find new ways to beat these superbugs. These new superbugs don’t just give you a sore throat. They can kill.