Mike the Mad Biologist covers a story from Nature in which it has been shown that bacteria can evolve resistance to defensins, the small proteins your body uses to defeat them, mainly deployed in yoru mouth, nose etc.

In people, natural bacteria-fighting compounds kill microbes in places such as the mouth, eyes and skin. More than 800 such compounds, dubbed antimicrobial peptides, have been identified in humans, plants, frogs and other organisms.

Several drugs based on antimicrobial peptides are being developed, in part because of the rising problem of antibiotic resistance to conventional drugs such as penicillin.

So 65 years after the introduction of Penicillin we have MRSA, Methicillin-resistant Staphylococcus aureus, commonly knowns as a ‘superbug’ because it’s resistant to both Penicillin and Methicillin. In another 50-60 years we’ll more than likely end up with a vast range of bacteria which is resistant to our bodies’ own frontline defenses. Not good.