Antibiotic Awareness Week: We need rapid testing for superbugs now
20 Nov 2019
Bacteria breeds by splitting in two, roughly once every 20 minutes. In the space of just a day, that single bacterium can become 2,361,183,241,434,820,000,000 (or two sextillion, three hundred and sixty-one quintillion, one hundred and eighty-three quadrillion, two hundred and forty-one trillion, four hundred and thirty-four billion, eight hundred and twenty million) bacteria – give or take.
It’s almost impossible to fathom a number so extraordinarily large, particularly for something so extraordinarily small. Yet, that number helps explain how quickly bad bacteria can evolve to become a threat.
You see when bacteria divides, both new cells should be a perfect replica of the one they came from, except sometimes they’re not… Sometimes those new cells have a mutation, a little bit of genetic code that isn’t exactly the same as before. That mutation may not mean much at all, but what if it means that that single bacterium has the power to resist an antibiotic?
Now imagine that a patient with that infection has been treated with an antibiotic (amoxicillin say) and all of the non-resistant bacteria are successfully wiped out, we’re still left with that single amoxicillin-resistant mutant, with no competition, which in twenty minutes time becomes two, then four, then eight, then 16. So the infection proliferates and further treatment is needed.
If amoxicillin won’t do the job, we try another antibiotic, let’s say azithromycin. Maybe it wipes out the infection completely this time, or maybe the pattern repeats itself and we encounter another single resistant bacterium. This is how a superbug is born – the simple evolutionary principle of survival of the fittest.
“From the moment Alexander Fleming pioneered penicillin in the 1940s, bacterial strategies to adapt and outsmart antibiotics have been in play.”
At the same time, whether taking them for colds and flu (that are viral and not bacterial) or using massive amounts in animal feed as a growth enhancer, our ubiquitous overuse and misuse of antibiotics has hastened antimicrobial resistance (AMR). This has given rise to “superbugs” which no longer respond to antibiotics, but keep multiplying.
“Public health officials across the world rightly talk of AMR as a “catastrophic threat.”
Indeed, Public Health England recently warned of an approaching “tipping point” when life-saving drugs become useless, revealing that 19 untreatable superbugs have been discovered in the UK in the last decade.
Superbugs can affect anyone. From a child who gets a cut while playing and develops an infection, to elderly people who have weaker immune systems. Two months ago, a close friend of my elderly parents took a fall. He had surgery to repair a broken leg which initially healed nicely, but – in the hospital – he picked up a virulent bug and oral antibiotics did nothing. He ended up on a cocktail of IV antibiotics for more than five weeks before the multidrug resistant bug was brought under control.
The use of chemotherapy for cancer is also a cautionary tale.
As early as 2015, experts warned that more than a quarter of infections after chemotherapy are caused by organisms already resistant to antibiotics. Chemotherapy weakens our immune system and this makes patients vulnerable to infection. In India, for example, bloodstream infections caused by superbugs have become the leading cause of illness and death in leukemia patients.
We need a complete reset of our relationship with antibiotics. This includes a more disciplined approach to getting test results before starting a course of antibiotics, transforming the rate of unnecessary use. While there are exceptions, for the vast majority of cases, antibiotics should only be taken when a test confirms a bacterial infection.
This will become easier when rapid, accurate diagnostic tests become readily available. Today, the best evidence for guiding antibiotic choices is based on testing bacterial culture in a petri dish to see if it responds to treatment. This process takes place in a lab and can take two to three days for a result, imagine if this testing could be done at the point of care, in the doctor’s surgery or pharmacy (where 74 percent of antibiotic prescriptions in the UK are given) with results given in minutes rather than days.
“It is critical that we speed up the development of tools that enable us to use existing antibiotics in the best way, anywhere in the world.”
The casual use of antibiotics wasn’t so much of a problem when new ones were being developed. Since no new class of antibiotics have been discovered since the 1980s, a new approach is needed.
Developing a test that could work in a Birmingham GP’s surgery or a medical centre in rural Nigeria is a challenge, but it is also one that is being taken up with enormous energy. At the Longitude Prize, our goal is to accelerate the development of rapid diagnostic tests and competing companies are making significant progress in the race to win.
For example, there’s Mologic, based in Bedford, that is developing a test focused on sepsis, taking inspiration from the Clearblue pregnancy test design (which the team’s lead scientist, Paul Davis, helped pioneer). Or, there’s Module Innovations in India that has developed a credit card sized test that detects the bacteria causing urinary tract infections, helping guide effective treatment.
In 2017, Lord Jim O’Neill told us that antimicrobial resistance could kill 10 million people by 2050, overtaking cancer in that same period. Given that’s more than the population of London, of New York, we need to pick up the pace to find a rapid test. Thanks to the work of innovators across the globe, I would expect to see medical practitioners identifying a full range of bacteria using rapid diagnostics within five years.
In this Darwinian duel, a survival of the fittest between us and the superbugs, the race is on to drive innovation.
Just remind yourself now about how bacteria multiply, getting stronger, every 20 minutes.