by microorganisms – that the real war against disease is principally won. Elsewhere, we have pushed the limits of survival, notably in intensive care. This, the specialism in which I chose to train, is where antibiotic resistant organisms are most prevalent. Here, powerful antibiotics, essential in the treatment of life-threatening illness, are used routinely. These drugs decimate ordinary bacteria. But what they leave behind are hardy species that have begun to learn tricks that allow them to evade antibiotic drugs. As a newly qualified doctor in the late 1990s, I learnt about Methicillin Resistant Staphylococcus Aureus – the infamous MRSA – a bacterial species resistant to methicillin and all other penicillins. In the fight against it, there were a handful of exotic-sounding drugs – vancomycin and teicoplanin among them. These were supposed to be our last lines of defence, but antibiotic resistant bacteria became more and more common; as did species with new patterns of resistance. Drugs we had previously barely heard of became commonplace. New last-line drugs emerged to replace the old. We got used to this state of affairs; a steady escalation in the arms race between us and the bacteria. But the balance has been shifting steadily. In our hospitals and our GP surgeries we have abused the drugs that gave us such a huge advantage over infectious disease, using them