Dr Martin Westwell is a chemist at the University of Oxford who has carried out research into new and resistant forms of bacteria. He believes that in a few years' time, before new antibiotics are available to combat them, there will be many more harmful kinds of bacteria around. Thus diseases could 'bite back' and have a significant effect on human evolution once again.

How important has the discovery of antibiotics been in controlling infectious disease?
When antibiotics was introduced in the 1950s it was a revolution. Where once people were going into hospital and dying, now they were just treated with an antibiotic, sent home and they were fine. And that was the state of play for a number of years, right through the ‘60s and ‘70s, new antibiotics were being introduced and infectious diseases just became trivial, people didn’t worry about them.

But what happened is through the ‘70s while things were so good pharmaceutical companies and researchers weren’t looking for new antibiotics, they didn’t think it was such a priority. That’s meant that now we have a serious situation where pharmaceutical companies have estimated that for a few years in our hospitals we’re going to be going back to the bad old days before penicillin when trivial infections - cuts on the hands, surgical wounds, burns, things like that - will kill people because of bacteria that are resistant to all of the antibiotics that we’ve always had before.

Could you explain how our increasingly sanitised Western world may also be a cause of increased disease?
Before penicillin children’s immune systems were fantastic, they’d come against all this dirt, all this bacteria, all through their lives and they’d build up a really good immune system. Now we live in a sterile, sanitised environment and we think we’re doing good for our kids by doing this, but what it actually means is that their immune system never gets challenged, it never gets to work, it never learns how to fight off these bugs. And so if they get an infection that’s resistant to antibiotics their immune system isn’t going to be as good as the kids from a few generations ago who could fight off these bugs.

How will the problem of resistant bacteria impact on the process of selection?
This effect has only occurred over a few generations and so the selectional pressure as far as evolution is concerned hasn’t been very great. But if this problem continues and we don’t come up with new antibiotics and our immune systems continue to be as bad as they are, then we can see in a few generations time selectional pressure will be there, because lots of people will be dying from infectious diseases, including antibiotic-resistant bacteria.

How has modernisation affected the spread of disease?
One of the important factors for the diseases of the future is that of our changes in lifestyle. If you compare our lifestyle to that in the 3rd World or to lifestyles years ago, you can see that those changes have really brought on some diseases. So, for example, viruses that may have been in the world in a remote area for a long time and never broken out, now with communications and the changes in the way that people live, diseases like HIV, have managed to get a global hold and can spread around the world. And in the future, if we ever combat HIV, there will be new diseases, because these bacteria and these viruses will always come up with new ways of getting into human being and killing people, because that’s what these bugs need to do in order for them to survive themselves.

But hasn’t modernisation also given us the tools with which to fight diseases?
Humans of course think that they’re very clever because of all the technology that we come up with and all the ways that we have of getting around these diseases, but really that’s a very complacent position. In the 1960s the Surgeon General of the US said ‘it’s time to close the book on infectious diseases’. He thought that we had such an arsenal of weapons against these bugs that no matter what they did we’d always be able to come up with a way of defeating them. But of course the bacteria and the viruses are evolving, and they use this power of evolution to overcome everything that we do. And I think we’re just starting to realise now that even if we get past this problem where antibiotics are going to start to become useless, we’re still going to have to continue this war against infectious diseases, it’s really going to go on for ever and ever.

Could you put the problem of infectious diseases into the wider context of human evolution?
If you think about diseases like the Bubonic Plague, of course that killed millions of people in Europe and that could be seen as a selectional pressure – people were dying, the ones who had resistance to the plague survived and so essentially evolved, or took steps forward in human evolution at least, as they overcame the disease. Since the introduction of penicillin what’s happened is there’s been no selectional pressure from infectious diseases, we’ve always been able to overcome them, the people that have been killed have been in a minority. But if we really can’t find new ways to overcome viruses and bacteria that can kill people, in a few generations time that will mean real selectional pressure, because people who can’t overcome these diseases themselves with their own immune system will die, and of course that’s natural selection which could drive forward human evolution in the future.

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Content last updated: 17/07/2006

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