EDP column by Professor Ketan Dhatariya
“I have had the flu for a week but my GP tells me I don’t need antibiotics. I thought that if I had an infection, then these would be needed. Is my GP wrong?”
Your question is a very common one. There are several different classes of ‘bug’. The main ones in Norfolk are bacteria and viruses. Others include fungi and things you may not think of like worms and ticks. However, luckily, many of these are often found in warmer climates.
Bacteria were first seen in 1674 when the microscope was first invented by Anton van Leeuwenhoek. Viruses are much smaller and can usually only be seen by using a powerful electron microscope.
Bacteria are single celled organisms that usually can live without any need for another organisms Antibiotics work on bacteria. There are also some very specific drugs that work on viruses known as antivirals, but these are very few when compared to the different sorts of antibacterials. Examples of antivirals that you may have heard of include ‘Tamiflu’ (the drug that is currently being stocked in case of an influenza epidemic), and many of the drugs used to treat HIV / AIDS. You may also have heard of or used Zovirax ointment for a cold sore. Unlike bacteria which can be free living, viruses are parasites and must live within other cells, and often die very quickly if they do not find a suitable ‘host’. To specifically target the virus whilst leaving the surrounding cell intact is very difficult.
Antibiotics that you may be familiar with include penicillin, erythromycin and tetracycline. These work in different ways and are used for treating bacterial infections. Many bacterial infections may occur alongside a viral infection, but the pattern of illness associated with viral and bacterial illnesses can be different. It is important to tell your doctor what has happed to you when you have been feeling unwell, so that they can use there experience and knowledge to decide what kind of infection you are likely to have. Occasionally they may want further blood tests or swabs to find out exactly which bacteria you have got. This is important because not all antibiotics are effective against all kinds of bacteria. For instance, MRSA (Meticillin or Multi Resistant Staphylococcus Aureus) is a bacterium that is resistant to the actions of several antibiotics. It is important to treat you with the correct antibiotic.
Resistance to an antibiotic can develop if the bacteria are not properly killed off by a course of antibiotics. If you are prescribed a course of antibiotics, then it is important to finish the whole course. If a few bacteria are left, then they may mutate and develop a way to become resistant to the effects of that antibiotic and so the next time the antibiotic is prescribed, it may not be effective. Thus it is important to finish the course even if you feel well.