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 illustration). 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). Overall, more bacterial cells will now posses this mutation and thus be resistant to the antibiotic, making it harder to eradicate the infection.
- Transduction
- Transformation
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.
The Rise of the Superbug
According to WHO (World Health Organisation1), global increase in antibiotic resistance is one of the largest threats to human health today. During winter many people experience 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 doctors 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?
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.
How do we overcome resistance? 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.
References
1) World Health Organisation