“Drug resistance follows the drug like a faithful shadow.”
– Paul Ehrlich
Antibiotic resistance. By now, a lot of people have heard of it – MRSA, or methicillin resistant Staphylococcus aureus, has become something of a celebrity in the bacterial world – but many people find it hard to understand. After all, how can a single bacterial cell learn to defeat a carefully designed antibiotic? Over my next few posts (probably 4 in total), I will explain that bacteria are quite capable of learning to defeat antibiotics, and what Ondine is attempting to do to stump them.
Bacteria have grown resistant to classically designed antibiotics under (and in) our noses for decades. How did they do it? The overly simple answer is that we exposed them to every drug we had over and over again and they figured out what to do. We kept giving them the blueprints, and it was only a matter of time before they found the inherent weakness in each design. We taught dangerous bacteria to resist our most potent medicine – like giving Kevlar vests to violent criminals.
The idea that we have educated bacteria lends itself to an analogy that I like to use to explain how this problem occurs, and why it escalates so quickly:
Imagine that bacteria are students in a class and that humans are the lecturers. Before antibiotics, the lecture was more-or-less always the same: the human immune system (it could be argued that, with acquired immunity, we were the students at the beginning, constantly learning from the bacteria that held tenure at this biological university). When antibiotics became a part of the curriculum, the students had some trouble keeping up. In the early going, class would quite often be cancelled when students simply couldn’t grasp the material. These classes were our success stories, the miracles of modern medicine – the complete eradication of an infection… But, much as every class has a couple of good students to match the poor ones, each bacterial population has mutants, and some are stronger than others. It is no surprise, then, that every once in a while a bacterium will find a way to ace the test posed by a new antibiotic. These star students are the genesis of the problem.
I’ll expand on this analogy in a couple of days.