When I think about all the ways an apocalyptic mass extinction event could happen I always think of an asteroid hitting the earth, a nuclear war breaking out, or AIs taking over the earth (https://www.sciencealert.com/which-apocalypse-is-the-most-likely). Needless to say, I posses unbridled imagination.
Recently I have been willing to consider a fourth, but possibly the most likely way humanity would meet its demise, THE ANTIBIOTIC APOCALYPSE (loud echos). What if I tell you that unknowingly we are engineering a super bacterium that could kill millions of people? Would you believe that? Read on and you will…
So first things first, what are bacteria? As most of you know, they are single celled organisms that are found everywhere. But don’t let their small size and seeming simplicity fool you. They are among the oldest living things on this planet and they are masters of survival. Most of them are harmless though and our own bodies host trillions of them and they aid us in our survival too. There are some others though that can be pathogenic and spread quickly and kill us. Millions of people used to die as a result of bacterial infections until antibiotics were invented. Antibiotics revolutionized medicine and saved millions of lives.
Antibiotics kill the vast majority of susceptible bacteria by slowing down their growth, or by preventing bacterial DNA replication, or making pores in the bacteria and simply ripping them apart. But as we evolve, so do bacteria (albeit at a much faster rate than us). By pure random chance, a small minority of the bacteria invading our bodies might have devised ways to protect themselves (for example by intercepting the antibiotics and changing the molecule so it becomes harmless or inventing pumps that pump the antibiotics out before they cause harm).
A few random bacteria developing this immunity will probably not be such big of a threat anyways, right? Think again! How have bacteria survived all this while? By Communicating, Changing and Transforming. If one or few bacteria successfully evolve and escape, they will be able to spread this immunity. Bacteria have been doing this for ages by exchanging plasmids (small extra-chromosomal DNA). They can exchange plasmids by just touching each other or can even harvest them out of other dead bacteria. This way immunity conferring plasmids can spread quickly through a bacterial population. There is no limit to how many of such plasmids (conferring different immunities) a bacteria can harbor and this can lead to the evolution of super bugs. In fact many of those super bugs have already been identified.
Two places are best known breeding grounds for super bugs, hospitals and livestock enclosures. Antibiotics are prescribed rampantly in various parts of the world, giving bacteria more avenues to encounter them and get immune to them. Antibiotics should only be prescribed/taken as a last resort and not because we think we feel colder than usual.
Another BIG problem is the antibiotic use in meat production. Today the world holds about 30 billion animals for livestock. To make sure we can get that cheap $3.99 meat product animals are kept in horrible conditions in very tight spaces and unhygienic enclosures. So many of these animals that end up as cheap meat products are given doses of various antibiotics to prevent them from getting sick. Unsurprisingly many super bugs resistant to most antibiotics have been identified recently.
To counteract a super bug infection, we do also have super antibiotics which are a last resort when in a hospital a patient shows symptoms of a super bug infection. These are antibiotics like Colistin, which are rarely used, highly regulated and ONLY prescribed as last stage antibiotics to kill bacteria that have become immune to a whole bunch of other drugs.
In 2015, scary news arrived from China, resistance against Colistin had been identified. This was really bad news because super bugs immune to the last line of antibiotic defense against them were just found. This could easily lead to a lot of people developing this infection and dying. When the origin of Colistin immunity was traced back it was found that livestocks in Chinese pig farms were being given Colistin against regulations. Resistant bacteria thus developed spreading from animal to animal and then to people without being noticed.
On an average day there are over a 100,000 flights connecting all parts of the world so its very easy to imagine a scenario where one or some people harboring such immune bacteria can transmit it to different people or animals in the world resulting in a dangerous pandemic spread. In fact even back in 1334, before antibiotics, what’s known as the Great Plague of London actually started in China and spread along trade routes, wiping out entire towns. Florence, Italy, lost a third of its 90,000 residents in the first six months. Overall, Europe lost 25 million people.
Discovery of antibiotics has prevented pandemic deaths for quite some while in human history but with lax personal use by humans and in meat industries; combined with modern travel infrastructure, are we developing tools for our own demise? Only time will tell.