This sort of thing concerns me as, lets take hand germs for example. If you constantly are using Anti-bacterial soap, and Purell and that sort of thing, what happens is SURE you kill off MOST of the germs. However, the one's that are able to surivive such an effert end up becoming "super germs", able to resist even 99.9% killing rate. That 0.01% ends up being some BAD Mo-Fo Virus or morph-bacteria that is able to surive even the worst drug effects. If it does indeed survive a doctors round of anti-biotics too, you now have a sincerly problematic germ on your hands. In fact we have seen a rise in things like MRSA (which took my mother during an attempted recovery from a brain aneurism at age 59) since the induction of super germ killing agents into society. And there are other germs that are similar or even worse that we can not remove from places like hospitals. The more sterile we become, the stronger the germs become. We kill off the germs that mean us little harm, while the harmful ones are becoming stronger and stronger, until one day we invent the process for a totally anti-biotic resistant ailment to come along.
But my point is that, as we fight harder to rid out word of germs, we are in a way making them stronger, and heading for an epedemic in the not so distant future, perhaps something akin to Plauge like. The irony that most people don't realise is that we are made mostly of bacteria as a human. Without bacteria, we would be unable to break down food properly to be able to consume food each day. Although on the same note, some of the same bacteria left on your teeth can sure punch a whole in your teeth. So, basically we are in a microscope fight daily with these "bugs", and the more we fight them off, the stronger they become. Similar to war, the more you blow a country up, the more they want to do the same to you. Using offensive techniques often is not the best outcome in the long term