There are a number of various types of bacteria that naturally exist in our bodies and help us in different ways.  Unfortunately, bacteria get a bad reputation.  Most people are unaware of how important these organisms are.  It is estimated that in a healthy person, there are about ten times as many bacteria cells as human cells!  Fluctuations in the level of these bacterial cells can lead to problems such as digestive issues, skin problems, obesity, and more.  It is important to think about the way bacteria cells function and evolve when we consider our own health. 

If an individual becomes infected with harmful bacteria they may be prescribed antibiotics to rid the body of that infection.   As the antibiotic begins to work, the harmful (and some helpful) cells will be killed off but not all of them.  When start to eliminate a number of the bacteria making you ill, you will probably start to feel significantly better.  At this point it is important to continue to take the antibiotic until the prescription is complete.  The reason is that after a few days of the antibiotic some of the harmful cells will still be alive in your body.  It is possible that these cells will take up genes for resistance to the antibiotic from some of the other bacteria that are already living inside of you.  These harmful cells with newly acquired resistance genes will divide and produce clones of themselves.  Unfortunately you will start to feel sick again and if you tried to take the remainder of your antibiotic they would have a defense against it.  

The fact that different types of bacteria can share genes enables them to survive under selective pressure.  Just one of the amazing charactericstics of these simple cells.  Although we may think of bacteria as a nuisance they have much to teach us.