Bacteria! They’ve been ruling the earth for ages, and are found everywhere. Under the sea, in the air, on the earth surface and millions of them are crawling right upon your skin and staying inside your body. Thankfully, most of them are harmless, friendly, and helps you in biological functions such as digestion and immunization.

But there are a few dangerous ones that have bugged humanity for a long time, and are responsible for spreading diseases like pneumonia, and other infections that spread like wildfire and can be fatal. This rampage of invading bacteria continued for centuries until 1928 when Alexander Fleming, a bacteriology professor discovered Penicillin, the first true antibiotic. A drug that kill germs in the body. But the question is: How do Antibiotics do this?

Although bacteria might come across as a simple single celled organism, there is a complex mechanism working inside its body that keeps it alive. So antibiotics disrupt this complex mechanism by stopping its metabolism, which slows down their growth rate, which helps to get rid of them easily. Some antibiotics prevent successful DNA replication, in bacteria, by targeting it gyrase, an important enzyme that helps unwind DNA for replication. By removing gyrase from the equation, antibiotics successfully prevent the bacteria from multiplying, that ultimately kills them. While some other antibiotics tear the outer wall of the bacteria so that their inner parts peel out and they perish ASAP.

But after losing the battle against the antibiotics for years, in recent times, a small minority of bacteria have started to regain their strength and are constantly developing ways to protect themselves, making more of our antibiotics are become less effective. This brings the question: Why and How?

Well, the answer to this is Darwin’s rule of evolution. Like any other organism, bacteria can undergo random mutations that give them the tools to protect themselves. Some bacteria have found a way to intercept the antibiotics and change its molecules so that it becomes ineffective, or they have developed pump-like antibodies that eject the antibiotics out of their body before it can harm them. Not only that, but some species can also release their DNA upon death to be picked up by other bacteria and others use a method called conjugation, connecting through pili to share their genes, and as time goes by, this leads to the formation of super-bacteria, a powerful bacteria that is immune to multiple antibiotics.