Sketchy Science: antibiotics

Showing posts with label antibiotics. Show all posts

Wednesday, 15 April 2015

Medieval Medicine: Fighting Modern Infections with Long-Lost Potions

Looking back at the history of medicine is usually an exercise in presentism. It is supremely interesting and plenty of fun to learn about the things that people used to think were medical problems (like hysterical, disobedient women) and the treatments they came up with to treat them (eye of newt, anyone?). The problem with presentism is that we assume modern medicine is better than what came before it, but the truth is, ancient doctors sometimes knew things that we have since forgotten. Just as ancient cultures were often better as sustainably making use of the environment than we are now, it should be no surprise that they were skillful at treating what ailed them.

A perfect example of ancient acumen popped up earlier this month in science news columns around the world as researchers and historians at the University of Nottingham in the UK cooked up an ancient brew to combat an infection that even modern meds have trouble fighting.

“Take cropleek and garlic, of both equal quantities, pound them well together… take wine and bullocks gall, mix with the leek… let it stand nine days in the brass vessel…” read the 1,000 year-old Anglo-Saxon text from which they pulled the recipe. The potion was used to treat “stye,” otherwise known as an infected eyelash follicle.

The bacteria at the heart of the infection is known today as methicillin-resistant Staphylococcus aureus (MRSA). The key thing to note in that name is “methicillin-resistant,” meaning that the bacteria are of the sort that we learned about last year in our semi-fictional story about Curious Geoff and the Antibiotic-Resistant Superbug. So if our most powerful antibiotics today have a tough time with MRSA, how did the ancient remedy fair?

As you might have guessed based on the existence of this article, the answer is pretty damn well. It should be noted that the researchers needed to make a few modern revisions to the recipe. Garlic and leeks have changed a lot since the 9^th century and brass vessels are both expensive and difficult to keep sterile (the researchers ended up using glass bottles with pieces of brass immersed in the other ingredients). In the end, however, the tweaks didn’t seem to reduce the effectiveness of their medieval gunk. The concoction killed 90% of MRSA bacteria, the same proportion as the conventional treatment that doctors use today to treat infections, called Vancomycin.

This isn’t the first time we have rediscovered an ancient medical treatment that rivals modern scientific wizardry. Artemisinin, a potent drug in the treatment of malaria was discovered by the Chinese military in the 1970's as they combed through ancient texts looking for treatments they could use to keep their Vietnamese allies healthy as they fought a war with the US. We also still use leeches to help relieve patients of infected blood. What this most recent discovery means, however, is that we might be able to pinpoint why it kills resistant bacteria and use that knowledge to develop treatments for other antibiotic-resistant infections.

As bacteria continue to evolve resistance to our best treatments, we will need all the help we can get. Some of the answers will likely come from nature as get better at making use of plants, soil bacteria, fungi, etc. But as counterintuitive as it might seem as we ponder the future of medicine, it occasionally pays to look deep into the past. You never know what you might discover if you keep an open mind.

Tuesday, 13 January 2015

Savior From The Soil: The First New Antibiotic in 30 Years!

Frequent visitors to our little corner of the internet may remember that last April we told a semi-fictional story about antibiotic-resistant bacteria entitled Curious Geoff and the Antibiotic Resistant Superbug. The gist of the story was the true fact that all over the world bacteria are becoming stronger and are better able to resist the drugs we use to treat them. This is a serious problem given that a new antibiotic drug has not been discovered since 1987… until last week anyway.

On January 7, 2015 the journal Nature published an article by a group of researchers reporting the discovery of a new antibiotic. That alone would have been enough to pique the interest of the science and medical communities, but the authors went one step further in the boldness category and called their article “A new antibiotic kills pathogens without detectable resistance.” As boring as that might seem, in the world of medicine it is the equivalent of calling your paper “Tyranosaurus discovered running surf school in rural New Zealand”… Basically no one was expecting it.

The new drug is called Teixobactin and in trials with mice it has been shown to effectively fight staph infections and antibiotic resistant forms of tuberculosis. That is big news given that the usual option for treating the latter is to prescribe drugs you know won’t work and cross your fingers really hard. Better still, the new antibiotic appears to have no side effects and can be given to mice in doses that make it practical for human use. That is, it doesn’t take a barrel of medicine to get them healthy again. Teixobactin works by inhibiting the growth of cell walls by bacteria, giving the immune system a fighting chance against them off.

So how did these researchers do it? How did they break science’s 30 year shut-out streak with regards to developing new antibiotics? Well, it turns out that the method they used might be even more of a breakthrough than the discovery of the drug itself. See, the thing about antibiotics is that the effective ones tend to come from bacteria that live in soil. The trouble is that we humans are pretty terrible at convincing soil bacteria to live and grow in labs. In fact, pretty much every one of our 100 or so antibiotics come from the roughly 1% of bacteria that we can get to grow in petri dishes. That means that 99% of the potentially world-changing drugs that exist in nature have been unavailable to us until last week.

The researchers on the new paper developed a technique that tricks soil bacteria into thinking they are at home when really they are doing our bidding. The approach makes use of what the researchers have termed the iChip, despite Steve Jobs not being listed as an author. It works by suspending bacteria in what basically amount to mini-petri dishes with semi-permeable walls, meaning some things can get in and out. Each iChip contains many of these little bacterial prison cells and is suspended in the type of soil that the bacteria usually thrive in. The result is that the bacteria have access to the nutrients they need to grow, but scientists are still able to isolate the bacteria from the soil for their experiments. This sneaky method of growing bacteria might finally give researchers access to an incredible number of new drugs.

Now, a caveat: this does not mean you can disregard all the advice you’ve been given about antibiotics. Teixobactin may be promising but it is nowhere near the point where you can get it from your local pharmacy. It still has to go through human trials, which could take as long as ten years… but hopefully more like 5. In the meantime, we still can’t afford to prescribe antibiotics willy nilly. Every time a farmer gives a healthy cow antibiotics so it can grow faster, we give up a little bit of our edge. Every time you leave a few pills in the bottle after you start feeling better, we lose some ground in the war on germs.

So remain diligent. Be smart about your use of antibiotics and don’t underestimate the enemy. This new paper may give us some hope and a nifty new trick for developing drugs; but until we truly master the soil, we are at evolution's whim in the fight against resistance.

Wednesday, 9 April 2014

Sketchy Science Storybook Corner Presents: Curious Geoff and the Antibiotic-Resistant Superbug

The following is loosely based on actual events... But we made up a lot of the non-sciencey bits.

“Why didn’t you see a doctor sooner?!” exclaimed the man in the yellow hat.

“Mind your own business.” Geoff replied in his increasingly raspy voice to the only other person in the waiting room. He didn’t even know this guy and after five minutes of conversation he was getting a lecture on personal health? There were days when the usually agreeable illustrator for the 6^th most popular Canada-based, illustrated science blog on the internet would have tolerated unsolicited advice, but this wasn’t one of them.

What had begun as a tickle in his throat had progressed over the past month to become an omni-present burden on his existence. Every swallow and syllable he spoke ignited an intense fire just below his jawline and Geoff had had enough. Fortunately he didn’t have to deal with this guy or his questionable fashion sense anymore because the doctor’s receptionist stood and called his name before a fist-fight could break out.

“Why didn’t you come see me sooner?!” The doctor asked. Still holding the recently-used tongue depressor in her right hand, the question seemed all the more accusatory. Geoff didn’t really have an answer aside from his hope that whatever was wreaking havoc on his esophagus would work itself out.

“I’m going to give you some antibiotics. Make sure you finish the bottle, even if you start to feel better.” The doctor scribbled something onto her prescription pad, ripped off the page and handed it to Geoff in the manner of an irritated police officer writing a ticket to someone caught speeding home to watch the season finale of The Biggest Loser. That is to say, she was both irritated and disappointed.

Over the next week, Geoff dutifully obeyed the doctor’s orders. Twice a day he summoned his courage and drank a tablespoon of the goopy, greyish antibiotic. "At least it came with a cool spoon shaped like an alligator" he thought to himself.

Pretty soon things appeared to be getting back to normal. Inside Geoff's body the medicine was beginning to turn the tide in his favour. Antibiotics can either kill bacterial cells directly by impairing their ability to build cell walls or they can smother them, binding to receptors on the outside of the intruder cell and stopping it from interacting with the body. Geoff’s medicine did the latter and it did it quite effectively… That is, until the weekend rolled around.

Earlier in the week, Geoff had considered cancelling his planned weekend adventure to the maple syrup factory with his friends. Now that he was feeling better, temptation got the best of him. By Friday he could hardly believe he had ever been sick. He loaded up his suitcase, got on the bus and rode to meet his friends. As he closed the door and turned the key to lock it, the half full bottle of medicine sitting on the bathroom counter was the furthest thing from his mind.

By Monday night, the game had changed. As Geoff indulged his sweet tooth with his friends, the bacteria in his throat had regrouped. Many of them had been killed the previous week by the medicine, but those that were left were the strongest of the strong. There had only been a few of them left when Geoff got on the bus, but in the absence of the killing blow from the medicine, they had multiplied. To make matters worse, a new bacteria had found it’s way into Geoff’s throat over the weekend. It was a largely harmless bacteria but it contained a piece of DNA that helped it form a smooth, slippery outer membrane.

This new bacteria made friends with the remaining disease causing bacteria and (as bacteria sometimes do) they traded DNA. Now the bacteria that the medicine had been meant to kill had mutated so that the antibiotic could not stick to them properly.

The new and improved super-bug used its good fortune to regroup.

Things had gone from bad to worse.

When he got home, Geoff resumed taking his medicine, but it was too late. The super-bacteria continued to multiply, unimpeded. He went back to the doctor who prescribed stronger antibiotics, but before long Geoff found himself in the hospital.

The next few weeks were rough on his body, but fortunately he was a young, physically fit person and over time his body was able to fight off the infection. He lost a bunch of weight and had a miserable time (despite having all the jello he could eat), and as he left the hospital he vowed to never let a bug turn super on him again.

Geoff would never know it, but the reason that his infection was able to mutate was because of the steak he enjoyed on Friday night. Many farmers around the world use antibiotics to help their livestock grow larger, faster. Over-using antibiotics gives bacteria more chances to evolve resistance to them. That is exactly what happened with the bacteria that eventually traded DNA with Geoff’s infection.

From that day on, Geoff did his part to combat the evolution of antibiotic-resistant bacteria. He didn’t take antibiotics when he had the cold or a flu because he knew that these infections were caused by viruses and not bacteria. Viruses aren’t alive in the same way bacteria are, so antibiotics are useless against them. He also stopped using antibacterial hand soap and instead used alcohol-based hand sanitizer which bacteria can’t evolve resistance to. Over many years, Geoff’s good behaviour influenced his friends to do likewise. Eventually even farmers got the message and stopped needlessly pumping animals full of medicine that could have been used to help creatures that were actually sick.