According to WHO (the World Health Organisation), the global increase in antibiotic resistance is one of the largest threats to health today. In the midst of a particularly chilly winter here in the UK, many people are experiencing colds and flus, with the occasional stomach bug thrown in for good measure too. It’s at this time of year that many people go to their GP’s in search of a quick remedy to what can sometimes feel like a never-ending cough or runny nose. However, when you go in search of such miracles in the form of antibiotics, could you be doing more harm than good?
To deter you from the unnecessary use of antibiotics, here I will explain how bacteria gain resistance to help you better understand why it is so important to only take antibiotics when absolutely necessary, and ensure you take them correctly.
First of all we should establish what antibiotics are actually for: BACTERIAL infections (e.g. chest infections, pneumonia, UTIs (urinary tract infections) etc.), NOT viruses (e.g. the common cold, flu etc.). Secondly, it should be stated that it is the bacteria itself which becomes resistant, NOT us as individuals.
So how does bacteria develop resistance? Bacterial cells divide and multiply rapidly. As a result, mutations will arise because the bacterial DNA is copied too quickly and thus, errors in the DNA sequence will occur. When an antibiotic is taken to combat a bacterial infection, some bacterial cells may possess mutations which make them resistant to the drug. As with natural selection, those bacterial cells which are resistant to the drug will survive even after a full course of antibiotics. You are likely to feel better, and not notice the infection anymore as the number of resistant cells would be negligible. However, these cells will stick around, divide and reproduce. Therefore, the next time you get this infection, there are more of the resistant cell type present and as a result, the symptoms you experience may not clear as the antibiotic will not have the desired effect, killing the bacteria. Eventually, your GP will give you another antibiotic which appears to get rid of the infection and you continue as usual. However, new mutations in the bacteria may have arisen as the infection grew, and so the resistance continues.
Alongside what can appear as a never-ending cycle of resistance, bacteria also have this ‘nifty’ way of making non-resistant cells, resistant! As if they weren’t annoying enough already. The process is called horizontal gene transfer (shown in the cartoon). Here, resistant bacterial cells will conjugate to (make a link with) a non-resistant bacterial cell. This enables a path to form between the two cells and they can transfer genetic data (i.e. share their resistant genes).
Another way in which bacteria achieve resistance is again by mutations, which this time make enzymes (nature’s catalyst (enables a reaction to occur)). The bacteria learn what the antibiotic looks like and will produce enzymes which can break down the antibiotic when they make contact with it. After all, bacteria are living things and have the ability to learn as we do.
How do we overcome resistance, I hear you ask? In order to achieve this, research is underway into new antibiotics which aim to address different bacterial processes than those currently targeted. A novel approach however, is looking to go back to basics and utilise something that has shown antibacterial properties for thousands of years: metals. Silver is used regularly in plasters to prevent bacterial infections in cuts (etc.) so now, scientists are investigating the use of silver in antibiotics. The exact mechanism is not known, but it is thought that as metals are not naturally found in a bacteria’s environment, bacterial cells are not able to form resistance towards them (yet!) and thus, silver can protect against bacterial infections.
To summarise, antibacterial resistance is one of the largest problems the World has to currently tackle. With the rise of resistant infections such as MRSA, super gonorrhoea, and bacterial meningitis, it is of the utmost importance for new antibiotic drugs to be founded, addressing different mechanisms than they already do. However more urgently needed, is the education of the public to ensure we all understand what resistance is, why it happens and thus, why it is so vital we only use antibiotics when absolutely necessary and use them correctly.