The name 'superbug' is a bit of a contradiction in itself. 'Super' is often used with a positive tone, implying that something is great or serves an important purpose. Superman is known for his heroics and the fact that he is, well... super. A 'bug' though conjures images of insects or germs. A 'superbug', by definition, can be one of two things. It can be a bacteria which is enhanced to better serve a purpose or function. Colloquially though, the term is used to describe a bacteria which has evolved to be resistant to the conventional treatment of antibiotics. A 'superbug' is known as a bacterium which cause uncontrollable infections, a microbe which can't be eradicated, a germ which can kill when normally it shouldn't.
Where have they come from?
The bacteria which are superbugs have humble and boring origins. Most of them were either normal commensals (bacteria which are found in and on the human body) or bacteria which cause mild infections. Over time though, these bacteria have changed and modified to behave out of character. These changes were, to begin with, small and went unnoticed by many thought of as nothing more than oddities. They have though, slowly and progressively, become better adapted to not only survive but to cause life threatening infections...and we don't know how to stop them.
How did they adapt?
The adaptations they've made have been driven by two primary forces. Firstly, through Mother Nature herself, all living organisms change as part of evolution. This evolution is what allowed us to develop into humans from our common ancestors. Secondly, human demand for immediate recovery to ailments, has led to a staggering abuse of antibiotics, which has allowed bacteria to become ‘super’.
So it's normal for cells to change?
Yes! Normal mutations to DNA are to be expected and are nothing to fear. Every time a cell reproduces it needs to copy its DNA and the machinery to do this isn't 100% foolproof. It makes copy mistakes, but about 99% of the time the new cell doesn't survive because of that mistake. Of the 1% left, the outcome can go one of two ways: either it makes the cell weak or it makes the cell strong. In those cases of a cell becoming stronger, evolution happens and the stronger cell takes over, for better or for worse.
So how are antibiotics involved?
"It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them, and the same thing has occasionally happened in the body.
The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant."
Alexander Fleming, 1945
Alexander Fleming discovered penicillin by accident but it revolutionise the treatment of bacterial infections. So much so, he was awarded a Nobel Prize in 1945 for which he gave a speech. The quote above is from the closing remarks of that speech; 72 years ago Fleming predicted the age of antibiotic resistance during his ultimate recognition of success. Every word he said has come true from the widespread availability, the under dosing and the rise of resistance.
Consider the bacteria as a small army in a neutral territory (that’s us humans by the way) which come under attack from an enemy, the antibiotics. The antibiotics work swiftly to begin with, killing off the weak bacteria in a matter of days. The neutral host observes how quickly the antibiotics have killed off most of the army and presume the battle over. They kindly ask the antibiotics to leave and assume the bacteria are gone for good too. However, some of the bacteria were watching and learning. Not attacking or raising their heads, they watched how the antibiotics attacked and they learned how to avoid the attacks. They tried out new tactics, some weren’t successful but those that were are taught to all new offspring members of the army of bacteria. Suddenly, the army is replete and the neutral host calls upon the army but now their attacks have no effect as the bacteria have learned to avoid them. Ladies and gentlemen, we now have a resistance.
So what next...?
It’s difficult to say. Resistance is appearing in all bacterial species and against all classes of antibiotics. Research is trying to design a new class of drugs, they’re looking at novel therapies such as nanoparticles and they’re looking at old forgotten therapies such as phage. Whatever happens, a change is needed and needed quickly to halt this emergent resistance