Jeremy Mode asked:
Are soaps and sanitisers breeding superbugs as well as antibiotics?
Chris - No, they're not. The reason I would say that is because when we use soaps and things what the soap is actually doing is dislodging dirt, grease and effectively bacterial food from your hands as well as the bacteria themselves. This is assuming you're using them to get rid of bacteria. Your hands are a breeding ground for bacteria because they're covered in the vestiges of your last meal. They're covered in bits of you. They're covered in sweat. This is a bacterial banquet. If you come in with the soap what the soap does is to knock off all of that debris from places where bacteria could lurk making the hands much harder to provide a home for bacteria. It doesn't matter if the bacteria become resistant to the soap. What the soap is doing is making the hands into the equivalent of a Sahara desert instead of a bacterial oasis. That's why effectively washing your hands is good to get rid of bugs.
Kat - James also wants to know are soaps and sanitisers affecting our immune system? This theory that you need a certain amount of bugs and yuk to have a healthy immune system?
Chris - This is a huge can of worms. The answer is possibly but there's a concept called the “hygiene hypothesis.” This suggests that the immune system needs educating from a young age in order to tell the difference between friend and foe. The way it does that is by exposure to things in the environment that we need to know are friendly and the things that are not friendly. Some people suggest that non-exposure to the things that are both friendly and moderately nasty – if you don't let your immune system learn to recognise those then the immune system almost twiddles its thumbs and says well, if I'm not doing that then I might as well react to everything. You get this hyperactive immune system that reacts to things it should be ignoring. It's a possibility.
Jeremy Mode asked the Naked Scientists:
Well, it is important to understand that evolution does not occur with in a single individual but in populations over many generations. So there isn't really any worry about something pushing the evolution of the human immune system. Additionally, most of these bacteria are on the exterior of the human and so don't stimulate the immune system anyway (of course, the chance of them getting in is why we wash the hands anyway, so obviously it can happen). In general the immune system is either working or depressed. You can't really supercharge it or boost it in any way.
Actually, evolution does occur with a single individual. It's just that it's only when the mutation in that individual confers an advantage over the other individuals and gets propagated through the species that we recognise that evolution has occurred.