(Disponível em português)
Often referred to in the media as silent killers, ‘superbacteria’ are one of the major public health threats of the 21st century. But what are they? And, more importantly, what can we do to fight them?
Just this February, the World Health Organization released a list of twelve families of bacteria considered ‘priority pathogens’, i.e., the ones governments and health organisations worldwide must strive to find a cure for (1). It is easy to understand why panic spreads so easily around this topic and it is understandable to think of these twelve microscopic ‘knights of the apocalypse’ as the impending fall of modern medicine. However, not all is lost and, rather than despair, we can do something about it!
The more correct term for addressing the phenomenon of ‘superbacteria’ is ‘antimicrobial resistance’, but even this expression is often misunderstood, as it sparks images of sentient microscopic revolutionaries, actively fighting against the antibiotics we throw at them.
‘Superbacteria’ are in fact nothing more than strains of bacteria which have evolved to become resistant to most (or all) known classes of antibiotics. This happens, not through some conscious effort to deter human activity, but through what is called selective pressure.
Very simply put, selective pressure happens when an environment becomes so hostile that some traits, which were already present and provide some sort of advantage, allow their carriers to live longer, reproduce, and pass those traits on to the next generation. This usually happens over the course of a very long time – thousands and thousands of years; however, bacteria are particularly susceptible to selective pressure because of their incredibly fast life cycles. In ideal conditions, such as in a culture in a laboratory, some colonies of bacteria have been known to duplicate their numbers in less than 20 minutes. This means that every time a bacteria undergoes binary fission and divides into two cells, its traits are being carried over into the next generation. Every cycle, the number of cells with a particular trait, assuming it is not selected out, duplicates.
So what exactly caused these ‘superbacteria’ to evolve in this way? Although partly a natural phenomenon, the misuse and overuse of antibiotics is largely considered to be the key factor in the fast development of ‘antimicrobial resistance’.
After Sir Alexander Fleming discovered penicillin in 1928, the world entered what is often called the ‘antibiotic era’. Common fatal diseases were quickly cured and infected wounds were no longer death sentences. Antibiotics swiftly became one of the most important medical breakthroughs of the century and quite understandably so – it is incredible to think that World War I, for example, was fought without access to antibiotics as we know them.
However, this exhilaration with antibiotics led to their prescription for every instance of a possible infection and, in certain countries, people would even buy them over-the-counter and self-medicate. This led to confusion over which diseases were treatable with antibiotics (such as colds versus the flu) and to an almost prophylactic use of antibiotics by the general public. This overuse meant that bacteria susceptible to antibiotics were being killed, and bacteria which were naturally more resistant to antibiotics were being allowed to thrive without competition. This is mostly what originated multi-resistant bacterial strains.
So what can be done about this? Well, it is easy to think that a major public health crisis such as this should be dealt with by the proper authorities, such as the World Health Organization, health systems around the world, governments, research laboratories and so on. And this is true, these institutions do have an amazingly large part to play in the prevention of a ‘post-antibiotic era’. They are currently working on constraining antimicrobial resistance through different measures: striving for the reduction of antibiotic prescriptions, preventing hospital infections and cross-contamination, looking for novel classes of antibiotics, etc.
These are all very important steps. However, each and every one of us can play a significant part in the fight against antimicrobial resistance; hopefully now that we understand how we caused it in the first place, it is easy to see how to fight it:
- Never buy antibiotics without a prescription. A doctor must always be the one to deciding whether or not to prescribe an antibiotic, no matter how certain you are that your illness is caused by bacteria.
- Always finish the course of your prescribed antibiotic. Even when you start feeling better, that doesn’t mean the infection is gone; if you prematurely terminate your prescribed antibiotic regimen, the strongest and most resistant bacteria still left in your system will be spared and allowed to grow.
- Do not share antibiotics. They have been prescribed for a specific patient with a specific infection.
- Do not save antibiotics. If, for some reason, your doctor tells you to stop your current regimen and you have left-over antibiotic, discard it according to the appropriate system in place in your country (some countries require these to be collected at healthcare centres, pharmacies, hospitals, etc.)
- Don’t be scared of germs and don’t over clean. Most bacteria are harmless and the ones that aren’t are mostly kept in check by the harmless ones. By over cleaning and disinfecting, you are providing an environment of selective pressure which will allow for pathogenic bacteria to grow.
- Be informed. Learn about the specific guidelines and recommendations for antibiotic usage in your country. Knowledge is power and this is incredibly true in this case. Educate others with what you’ve learned if you can.
‘Superbacteria’ are not out to get us – but they will unless we all decide to do something about it.
Rita Figueiredo is a former immunology researcher now working in marketing and public relations in the pharmaceutical industry.
Edited by: Cecilia Mezzera(Page Editor), Clara Ferreira(Section Editor).