If you’ve been paying attention to the news for the past week, you may have noticed more than a few mentions of antibiotic resistance. Firstly, solving the problem of antibiotic resistance won the Longitude Prize, confirming its importance in the eyes of the public. Then, a few days later, David Cameron has been all over our screens warning that the problem could lead to our world being ‘cast back into the dark ages of medicine’. He has announced investigation into why so few new antibiotics have been introduced, and plans to encourage development of new antimicrobials. However, despite being mentioned hugely this week, however, this is far from a new problem.
Antibiotics are chemicals that are able to either kill a microorganism, often a bacteria, or inhibit its growth. Antibiotic resistance is the ability of a microorganism to resist the action of the drugs. This resistance arises naturally as a result of bacterial evolution. Just as with all other organisms, mutations can occur. If a mutation is beneficial to the organism due to ‘selection pressures’ in its environment, then the mutation is likely to stick. In the case of bacteria, the selection pressure is the presence of an antibiotic, and so a mutation that allows the bacteria to survive will be carried forward into the next generation. Since bacteria can share genes with neighbouring bacteria (horizontal gene transfer), the resistance can often spread rapidly through a population. Often bacteria become ‘multidrug resistant’, or as they are more commonly known, superbugs. In these cases we need to find new antibiotics to fight the bacteria, and this is where our problem lies.
As mentioned earlier, mutations will stick if there is a selection pressure, such as antibiotic presence. It makes sense, therefore, to only prescribe antibiotics when they are needed. Unfortunately, this is not what is happening. It is widely agreed that antibiotics have been inappropriately prescribed in the past, and probably still are. Patients have been known to insist on getting antibiotics when they are not necessary – for example, a third of people believe that they can take antibiotics to treat the common cold1 (which is a virus, and so completely unaffected by antibiotics). Another way to reduce the chance of resistance occurring is to ensure that patients complete a course of antibiotics. Just because you feel better, doesn’t meant that your infection is gone. Reducing or stopping a course of antibiotics can lead to reduced levels of the chemicals in your body, giving the organisms a lower level to fight against (and win). GPs and their patients need to be more aware of these issues in order to try and reduce the occurrence of resistance.
Inappropriate treatment of humans isn’t the only issue contributing to the rise of resistance. Nearly 50% of all antibiotics are used in farming – mostly in intensive livestock farms2. These intensive farms have crowded conditions which could lead to a fast spread of disease. A large proportion of livestock receives regular antibiotics, whether they are showing signs of illness or not. Paying for these antibiotics may seem like a large cost to farmers, but it can mean a huge saving if it prevents them losing their entire year’s income due to a disease outbreak. This issue has already been identified, and there are many campaigns trying to make changes to these antibiotic regimes on farms.
Solving the problem of antibiotic resistance isn’t a simple case of producing new antibiotics, however. If we are to stop this problem spreading, we need to learn how to treat our infections properly and treat the correct infection with the correct antibiotic. This is a case of improving diagnostics and hospital procedures, and this is where it is most likely that the Longitude Prize money will end up going – because it is a long-term solution and not a short-term one.
The issue highlighted by David Cameron this week is that there are no new antimicrobial drugs reaching the market. The case is that the pharmaceutical companies are not investing in sending these drugs to the market, and not because the research is not going on. It costs tens of millions of pounds to get a drug to the market – and in the world where resistance is occurring so easily, it is unpredictable whether developing a new antibiotic would be profitable. To imply that we are not discovering the antibiotics is certainly incorrect. I work in a molecular microbiology department who has a large group of scientists working with Streptomyces, soil bacteria whose antimicrobial products were discovered back in 1943. Many of these scientists are investigating whether we can use these bacteria to find even more microbial compounds. Elsewhere on site, researchers are investigating bacteria from insect guts for the same cause3. Elsewhere in the UK, research is being done to hunt for antibiotics from bacteria from deep ocean trenches.
Both the Longitude Prize and the following press coverage from David Cameron have highlighted a key issue in the world today. But we should not be investing all our money into finding new antibiotics, because this is not the solution we need. If we are to prevent even more superbugs emerging, we need to be focusing our efforts into understanding the bacteria, and understanding how we can fight them best. We need to be educating the public into the risks of treating antibiotics with less than the respect that they deserve, and we need to be making farmers do the same. Evolution will never stop happening, and so bacteria will never stop trying to become resistant. Maybe, however, we can slow the process enough to stop it from ‘casting us into the dark ages’.
The latest offering from the John Innes Centre YouTube page:
- McNulty et al. (2007). “The public’s attitudes to and compliance with antibiotics”. J. Antimicrob. Chemother.60 Suppl 1: i63–8..
All images from Wikipedia By Isabel Webb, a 2nd year PhD student in the lab of Prof Phil Poole