So, this is how it usually goes: We get infected with harmful bacteria, and if our immune system can’t handle it on its own, we use antibiotics. They kill off the unwanted intruders along with some of our good symbiotic bacteria. It’s not ideal, but a small price to pay when it’s a life and death situation. Overall it’s a pretty good system. Now, imagine a different scenario in which some bacteria become immune to our antibiotics. We would effectively go back at least 100 years in our medical history, before penicillin was invented in 1928. We would have no way of treating bacterial infections. Considering how fast bacteria can spread thanks to our modern ways of transportation, it could be a worldwide threat to billions. Sounds pretty scary, right? Well, it gets worse! Those kinds of bacteria already exist and we, as a human race, are hard at work to produce a lot more of them. Why? And what can we do to stop it?