What are antibiotics

A.� Basically they're chemical substances�that can, in low concentrations, either�kill harmful microorganisms or�curb their growth rate. This helps our�immune systems'�deal with�disease or infection and see off the�harmful�bacteria that are causing it.

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Antibiotics�-�penicillin, streptomycin and tetracycline are are some of the�most widely prescribed�-�are produced�by�pure chemical synthesis;�by selected microorganisms, in a laboratory; or semi-synthetically.

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Q.� How do antibiotics work

A.� Rather like a�highly specific weedkiller.�Each one�targets the particular�type of�bacterium it has been produced to combat, but doesn't harm your natural body�cells.

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Different types of antibiotic work in�different�ways. One�might stop

its target�bacterium�drawing energy from a body sugar like glucose, another would�attack its�ability to build�cell walls. Such actions cause�the bacteria to die�instead of reproducing.

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Unlike viruses,�bacteria are alive. They work by eradicating or disabling cells�competing with them�for nutrients. Because�they reproduce really quickly, a strain can�mutate and produce defences against�new adversaries. This is why doctors are now being urged to prescribe them more sparingly.

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Q.� Can I take antibiotics for a cold

A.� No, because a cold is a virus. Antibiotics do not work on viruses because viruses are not alive, they're just genetic code that become entwined with the body's normal genetic code, reproducing the virus.

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Q.� Why are antibiotics blamed for the evolution of 'super germs'

A. As we've already noted, bacteria are living organisms, they evolve and mutate. Antibiotics are see by many as 'wonder drugs', capable of curing anything and some medical professionals are concerned by their overuse.

There's no doubt that since their introduction, starting with the development of penicillin during the middle of the�20th century, antibiotics have saved thousands of lives. However they're not the panacea that some people perceive them as, having a specific application, notably only for use with a bacterial infection.

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The more antibiotics are used the more that the bacteria they're trying to destroy are exposed to them, giving them more chance to mutate and evolve into new strains of bacteria that the antibiotics are useless against: becoming so-called 'super bugs'.

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Q.� What can be done

A.� Basically patients need to stop perceiving antibiotics as miracle 'cure-alls' and doctors need to be careful about overprescribing, although patients often make this hard because they demand or expect antibiotics.

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Always complete the course of prescribed antibiotics, even though you may feel you don’t need them any more; you may leave the odd, stubborn bacteria in your body if you stop taking them halfway through. These few remaining bacteria are then exposed to the antibiotic, rather than being destroyed by it, giving them the chance to mutate and evolve to become resistant.

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Do you want to know how a type of medicine works Click here to ask.

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by Lisa Cardy