By Glenn Ashton · 26 May 2014
Antibiotic resistant bacteria have brought humanity to the dawn of a new era of medical uncertainty and risk. This has emerged through a simple evolutionary trend, where some of the most basic organisms on earth have managed to thwart our ingenuity over the course of slightly more than half a century.
Recent medical and scientific progress has extended human longevity well beyond the traditional biblical time-span of 70 years, across many parts of the world. One of the most important medical interventions of the last 70 years was the widespread availability of antibiotics to cure previously untreatable infections.
At the end of the Second World War there were less than 2.5 billion people. Today the earth is home to over seven billion. Besides improved nutrition and vaccines, a significant proportion of this growth can be attributed directly to antibiotics. Yet these wonder drugs are increasingly being outsmarted by the simple bacteria they initially vanquished. How has this happened?
Bacteria multiply incredibly fast; one of the most common antibiotic resistant microbes Staphylococcus aureus, commonly known as staph, divides every half hour. In five hours, a single bacterium can formed a colony of over 1000; five hours later it will be over a million strong.
Evolution is driven by genetic mutation; this is how organisms adapt to their environment. Given the size of staph’s genetic code, we can expect about 300 mutations in the first ten hours. In less than a day and a half the genome theoretically has the potential to exhibit every single possible mutation in that new colony.
This is the consequence of the exponential power of rapid cell division and mutation. The result is the inevitable adaptation of bacteria to environmental pressures, which in the health field include antibiotics. We use antibiotics to extinguish dangerous bacteria that have infected our bodies. But once bacteria have adapted, the antibiotic becomes ineffective.
This basic explanation illustrates our vulnerability to these rapidly adapting organisms. More specifically it highlights how vulnerable we are to the over-use and abuse of these medicines that revolutionised health care over the past three human generations.
It is not a matter of if we are going to lose our existing antibiotics, it is when. Our careless misuse of these medicines illustrates our inability to deal with the perilousness of our situation. We are so blasé we casually feed them, at sub-therapeutic levels, to livestock in order to accelerate growth. The result is a slew of resistant bacteria emerging from these livestock production facilities, directly into the animal products we consume.
Antibiotics are also excessively prescribed. This is encouraged by the conservative medical approach of doctors, dogged by litigation, who wish to reduce risks wherever possible. Improper use, such as not completing a full course, further encourages resistance.
This has led to elevated infection rates through even relatively minor medical procedures. High human and animal population densities harbour and incubate increased bacterial loads. Today, as in the time of our grandparents, we are under a real threat of serious infection through something as innocuous as a scraped knee or an infected insect bite.
Antibiotics have saved my own life several times. A septic foot as a child, a particularly nasty tropical infection as an adult, a bad tooth abscess and an agonising gut infection were all treated by antibiotics. The same goes for most of us. Statistically, antibiotics are prescribed more than once a year to every resident in some parts of the USA.
What happened before we had antibiotics? Nearly one in three cases of pneumonia were fatal. One of nine skin infections. Half a percent of mothers giving birth. I would probably not be here to write this article.
How bad are things presently? Let’s examine our example of staph infections: In 1974 2% of US infections were methicillin resistant. By 1995 it was 22% and by 2004 it had reached 64%. By 2007 more people in the US were dying from staph infection than from AIDS. Combine HIV, AIDS, TB and resistant staph and other bacteria and you have a ticking time bomb. This is of particular interest to Sub-Saharan Africa, along with other developing regions.
HIV and AIDS compromise our immune systems. Antibiotics therefore effectively become a substitute defence mechanism. As this region lies at the global epicentre of the pandemic it is clearly essential not to compromise the utility of antibiotics.
The same goes for what is known as drug-resistant and multiple drug-resistant (MDR) TB. This emerged mainly through patients failing to complete the full course of antibiotics. This caused the tubercular bacillus to rapidly evolve resistance to almost every known antibiotic. Today MDR TB can only be treated in isolation, along with the monitored dosing of patients by astronomically expensive medications.
Health experts and the medical fraternity are profoundly concerned by the rapid evolution of antibiotic resistance. Steps have been taken to address the problem, yet our present antibiotic arsenal has limited and shrinking possibilities.
The reality is that we have to explore new alternatives. The pharmaceutical industry is reluctant to do so because of the expense and increasingly short-term usefulness of new antibiotics; bacterial resistance has evolved more and more rapidly to the most recent antibiotics. If drugs are not sufficiently profitable, big pharma is indifferent to developing them. Consequently a strong argument has been made for state intervention in the research for new antibiotics.
Promising new antibiotic resources have been isolated in soil meta-genomes. Some of these are associated with the rich biota of the Fynbos region of Southern Africa, along with other mega-biodiverse regions. Other useful discoveries have been made through analysing various marine organisms.
Such opportunities need urgent funding for research. It would be useful, in the case for South Africa, for the generous existing government subsidies to biotech research to focus carefully on research toward development of new antibiotics. These could be rolled out by leveraging similar finance streams as used with new HIV and AIDS drugs, which access both public and private funding and keep eventual costs low.
We urgently need to see this situation for what it is - an emerging global crisis with potentially catastrophic possibilities for humanity. There are solutions but we must explore novel, practical methods to deliver them into the public health system. This challenge demands our immediate attention.