First of all, let us define the word ‘superbug’. More scientifically known as multi-resistant bacteria, superbugs are bacteria that contain several resistance genes. These genes can code either for enzymes which destroy or alter the antibiotic, or for the production of the efflux pump which can transport antibiotic compounds out of the cell. The genes tend to be found in the plasmids (rings of DNA) in the bacterial cells. This makes it easier for lateral gene transfer to occur, whereby genes have the ability to jump from species to species within the bacterial kingdom, and is one of the reasons that superbugs arise in the first place. Lateral gene transfer takes place via three different mechanisms: conjugation, transformation, and transduction. However, we shall not go into the details, as they do not concern us. It also allows antibiotic resistant genes to spread at an alarmingly fast rate, making it hard for scientists and researchers to find the appropriate drugs to kill off the bacteria quickly enough.
A specific type of bacteria will have many different strains, each carrying very subtle genetic mutations. This makes some of them more resistant to an antibiotic than others, and hence natural selective breeding between the bacterial colonies in the infected organism occurs, leading to increased germ resistance. This concept is known as survival of the fittest (one of the basic principles of Darwinian evolution). For example, if MRSA was present in a patient, and the patient was treated with the penicillin antibiotic, some of the bacteria would be destroyed, while other strains would be more able to cope with the drug and create resistance to it. These strains would then reproduce and spread, so that a new antibiotic would be needed in order to kill the bacterium.
The problem nowadays is that antibiotics are being overused and prescribed without being needed. This is as a result of the majority of the public who are under the false impression that all viral infections should be treated with antibiotics. Some doctors who feel they do not have the time to explain why and how it would not help may just prescribe it to the patient despite the consequences. So what are the consequences? In what way could a useless antibiotic prescription be harmful and potentially dangerous? Well, instead of killing off the bacteria present in the organism, the antibiotic would be solely helping it become resistant, in many cases leading to the development of the infamous superbugs. Day-to-day commodities such as antibacterial hand wash are essentially doing the same thing and making it more difficult for us to win this so-called fight against multi-resistant bacteria.
According to the World Health Organisation (WHO), around 10 million people die each year as a result of antibiotics that no longer work. 10 years ago, the pneumococcus bacterium – the cause of most cases of pneumonia, meningitis and ear infections – could be treated using any of 10 antibiotics. Nowadays, 1 or 2 of these antibiotics is left fully functioning. Even more recent, NDM-1 bacteria – a new superbug – is becoming of increasing concern. Even though there have only been 50 cases in the UK, scientists fear that it will become global. Why? NDM-1 bacteria carry a gene, which encodes an enzyme called NDM-1. This enzyme can fight and destroy the antibiotic(s) working against it, making it resistant to even the most powerful antibiotics (namely carbapenems). It can exist inside different bacteria, and so we fear that lateral gene transfer will occur. Consequently, this would allow bacteria that are already resistant to certain antibiotics to carry the gene for NDM-1 enzyme. In other words, the antibiotics that could be effective against these NDM-1 superbugs would decrease hugely as the gene spread and more NDM-1 bacterial communities formed.
So, are we losing the fight against superbugs? Well, as it is today, our only solution to the problem also seems to be one of its principal causes – antibiotics. Although their aim is essentially to fight the infection and kill off the bacteria, they are also unintentionally strengthening the resistance of many bacterial communities. To make matters worse, bacterial genes are constantly mutating, creating many different strains of just one type of bacterium. Not only does this mean that different antibiotics are needed for different strains, this also means that the naturally more resistant strains will survive the antibiotic course, thereby spreading and reproducing. And once the antibiotic made to fight off that particular strain has been put into practise, yet another strain may have been produced as a result of these subtle genetic mutations. Lastly, as you might already know, bacteria love to divide and replicate, and are very efficient at doing so. They can double their numbers in just 20 minutes. Meanwhile, lateral gene transfer may be occurring and causing other types of bacteria to become a threat too.
We are trapped in a vicious cycle, which at present, does not seem to be coming to an end.