A strange relationship exists between us and bacteria. On one hand we are constantly trying to kill them and on the other we can not survive without them.
No matter how much we clean ourselves, we will always have bacteria living on and inside of us. We have a symbiotic relationship with them. This means that we provide a suitable environment for them to live and in return they perform jobs for us. These jobs we can not do ourselves. Thus we can not live without them and they can not live without us.
Yet we are competing all the time for space. Our immune systems (and various other body mechanisms) are in place to keep the bacteria population under control. Failure to do this and the bacteria will run riot, multiple and take over our bodies. This is why, for example we have the urge/desire to wash. Our brains are in tune with our own scent and can identify when we smell and need cleansing. A large proportion of our scent, as you are gathering, is due to the size of the bacteria colony living on our skin.
However, being too clean can also have its problems. We see this amongst those who are classed as obsessive compulsive disorders when they may wash 4-5times a day, brush their teeth multiple times, etc. The consequences is that various bacterial colonies are destroyed and so the jobs they perform go undone. Our bodies then suffer because we can not do them.
Bacteria also keeps our immune system strong. The greater the exposure to bacteria the stronger our immune systems. All systems in our bodies work on a simple principle : the greater the exposure to a stimulus the better we become at adapting to it. Think of throwing a ball, playing a instrument, performing your job, hearing sounds, talking, anything in fact. The greater we do it the better we get. The same applies to our immune system. 100years ago we were exposed to thousands of bacteria daily, 1000yrs ago even more and 100000 yrs ago substantially more as our habits were more rural and technologically free. Our environments today are relatively sterile in comparison. Our exposure to bacteria is relatively low so our immune system gets lazy. Our weakening immune system is one of the many reasons why we are suffering from more coughs, colds and flus? Another of those reasons, is our reliance on medicine. Not only is our exposure to bacteria deceasing (due to the sterile environment) but when are immune systems are engaged (i.e. we have a cough, cold or flu) we provide extra help when it is not needed. Would you want somebody reading the paper out loud to you when you are perfectly capable of reading it yourself?
Now we are not implying that we should all live dirty, wash once a week and eliminate medications. Rather we should strike a balance, excessive cleanliness weakens our bodies as does excessive dirtiness. Giving our immune system a chance to fight the bacteria / virus means it grows stronger and thus reduces the frequency of future illness. Should our bodies struggle then consider sending in the second wave; medicine.