A post-antibiotic apocalypse?

Penicillin_cures_gonorrhea

‘An advertisement for penicillin as a cure for gonorrhea’. Today, drug-resistant strains are a growing problem. Image in the public domain.

Superbugs. Antibiotic resistance. The post-antibiotic apocalypse. Scary terms – and I hope you’ve heard something about these over the past year. We’re in trouble, yet many people aren’t aware that antibiotic resistance is a massive, worldwide problem. If we don’t find a way around this issue soon, we may find ourselves back in the dark ages as far as infections are concerned.

Antibiotic drugs are one of the most important medical advances that human civilisation has ever made. In the era before their discovery, even a small scratch could kill you. Common skin bacteria like Streptococcus and Staphylococcus could – and often did – kill people. During the American civil war in the 1860s, for every three soldiers killed directly during battle, five more died of illness or infection. Diseases such as cholera, gangrene and syphilis killed and disfigured hundreds of thousands of people before we discovered penicillin and its friends. Once we started manufacturing antibiotics, bacteria didn’t stand a chance. We crushed the microbes and entered a clean bright era in which people no longer succumbed to the lowly bacterium – death rates plummeted.

Antibiotics work wonderfully well, which is why we’ve been relying on them for the past 60 years. There are many different classes of antibiotic, and they fight infection in different ways. Some break up the bacteria’s protective cell membrane, making them more prone to lysis (breaking up). Some block bacteria from making essential proteins, or interfere with bacteria’s replication. Antibiotics are excellent at keeping bacteria from taking over your body, whether they kill bacteria outright or make them sitting ducks for your immune system. Many antibiotics are derived from compounds found in moulds and fungi, which have been defending themselves against bacteria for millions of years. We’ve studied those defences and improved on them, thereby developing synthetic drugs that work on the same principles.

What is resistance?

Recent investigation has shown that many of us don’t quite understand antibiotic resistance. We know it exists, and that it’s bad, but not necessarily why.

Despite the connotations of the word “resistance,” antibiotic resistance doesn’t mean that your body has built up a tolerance to a medication (as in how you need three cups of coffee to get started in the morning these days…).  Nor is resistance an allergy, in which your immune system reacts violently against foreign proteins and results in itchy hives on your skin. In fact, antibiotic resistance isn’t about you at all. Your sick body is incidental – you’re just one of the places where bacteria and antibiotics meet. Through unknowing misuse of antibiotics, you could be breeding antibiotic-resistant bacterial super-soldiers under your skin. But how?

Just like every other biological “arms race” in the natural world, bacteria have evolved defences to protect themselves from antibiotics. Some bacterial enzymes can neutralize antibiotics by snipping the molecules in half. Some mutations change the structure of the bacterial cell wall, so antibiotics have no way in. Some bacteria even manage to pump antibiotic molecules back outside themselves, so the intracellular concentration never gets high enough to do serious damage. How do they do it? The same way the X-men made their mark: mutations.

Everybody mutates a little here and there. It’s one of the driving forces behind evolution: random changes in genes may give an organism a tiny advantage over others. Hence this organism has a greater chance of surviving, reproducing and passing on the beneficial trait to its descendants. Over time, traits within a whole population may slowly change. In this particular case, some mutations allow bacteria to dodge antibiotics just a little better than their neighbours.

Bacteria grow incredibly fast: in ideal conditions, E. coli can double every 20 minutes, which adds up quickly. Add the selective pressure of a drug killing off the bacteria who are least able to fight it, and you gradually push a bacterial population towards antibiotic resistance. It’s made a little more complicated by the fact that unrelated strains of bacteria can swap genes back and forth via little chunks of DNA called plasmids. That leads to bacteria that are resistant to several antibiotic agents. We call those multidrug-resistant organisms, or MDROs, and they’re pretty serious business. Hospitals are working very hard to identify and isolate patients with MDROs as quickly as possible so that they don’t spread the bacteria to others, because if they do we have very few options to treat them.

Bugs we could once kill easily are now putting up an incredible fight, and we’re losing our advantage. Antibiotic-resistant organisms are a huge threat. Clostridium difficile (C. diff), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterobacter (VRE)… they’re making people very sick, they’re swapping genes around, and they’re becoming harder and harder to kill.

How did it get so bad?

Our overconfidence was our weakness. The drugs worked so well that we used them a lot, and didn’t put too much money or effort into discovering or developing newer drugs with different mechanisms of action. We didn’t need to – we’d conquered bacteria! We blasted away at illnesses with these magic antibiotic bullets, without properly considering what the long-term consequences of overuse may be. Unfortunately, misuse of antibiotics is a huge contributor to the creation of MDROs. Using antibiotics you don’t need, using the wrong antibiotic, or stopping a course of antibiotics as soon as you feel better: all of those cause antibiotic resistance.

Medical associations have been changing their guidelines as a result of the increasing problem of antibiotic resistance. Most of the coughs and sore throats and ear infections that bring a person to the doctor are caused by viruses, which means that antibiotics won’t help. Doctors should explain that to their patients and send them home to rest up with some chicken soup. But that’s not always how it works out, and plenty of patients still feel like they’re not being given proper care unless they leave with a prescription.

That’s not the whole problem, unfortunately. If it was just about prescriptions and vigilance, it would be easier to fix. But even if we can control every single human medical use of antibiotics, there’s a whole other side to the antibiotic resistance problem: animals.

Antibiotics are in widespread use in livestock operations – a sick animal isn’t a profitable animal, and prophylactic treatment to prevent infection in the herd is common. Moreover, it turns out that small doses of antibiotics tend to improve growth rates in chickens and pigs, so they get added to their food to help get them up to size quicker. Does that environment sound familiar? Antibiotics in prolonged low doses, taken when they’re not needed for an infection? It’s a perfect recipe for antibiotic-resistant organisms. The superbugs that develop in these animals eventually make their way into the human population through food products and waste runoff. And because the antibiotics used for livestock are often the same kinds we use to treat our own infections, we end up making the problem worse.

Experts warn that unless something changes dramatically and we get better control of the MDROs, we may soon get to a point where surgery will be incredibly dangerous because of the resistant infections that may take hold afterwards. That’s terrifying.

What’s the solution?

There isn’t really a good solution. At least, not an easy one.  Today awareness of the problem has increased, thanks to many scientists and writers making a noise about it, but it’s complicated. Researchers are making some progress towards developing new antibiotic drugs by examining soil for organisms with natural defenses we can use, as well as by synthesising new promising antibiotics from scratch. Using fewer antibiotics, both in people and in livestock, is obviously a good strategy. Culturing specimens in a laboratory before choosing a suitable antibiotic is another good way to prevent resistance. But antibiotics are used globally – who will set the rules, and who will enforce them?

It’s important for each of us to do what we can to help curb antibiotic resistance, by being responsible antibiotic users. Don’t beg your doctor for them. When you are prescribed them, ask why. Dispose of excess medications responsibly – many communities have special collections for medications so that they don’t end up flushed into the water. That said, you shouldn’t have any leftovers! Finish them all, even if you feel better after three days! Use regular soaps at home instead of the kind laced with antimicrobials. Buy meats that were raised and processed without antibiotics whenever possible. Above all else, wash your hands a lot – this may well stop you from becoming ill!

For more information about antibiotic resistance and why you should be worried enough about it to make some changes, I highly recommend that you follow Maryn McKenna on Twitter. She writes extensively, eloquently and passionately on the topic. (Don’t blame me if it’s harder for you to sleep at night after reading some of her articles!). We need to work together to avoid unnecessary antibiotic usage – otherwise, the post-antibiotic apocalypse could become a reality.

JenJen MacCormack (AntiJen) is a self-described “mad laboratorian” currently working on transforming human plasma into blood typing antisera. She’s approximately 40% coffee by volume and expends excess energy on her growing portfolio of science writing.

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  1. Pingback: Morsels For The Mind – 11/03/2016 › Six Incredible Things Before Breakfast

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