Bacteria Capable of Changing its Genes

Scientists have recently found a bacteria present in the Gut, that is able to change its Genes ! I dont have much information about this on the tip of my fingers, so here's a link :

english.sina.com...

I'm sorry, but that article about B. theta in the human gut does not actually say that it can "Change it's genes".
What the article specifies is that B. theta can change the expression of certain genes within it's genome with much more flexibility that might have normally been expected.
Within our own body for example, since we have specialised cell lines many genes are permanently turned off and their expression cannot be activated. The exception to this are pluripotent stem cells (Otherwise known as foetal stem cells) and adult stem cells (e.g. ethyropoeitic stem cells and myogenic satellite cells).
To find out some more interesting things about the relation between environmental pressures and genetic expression, I suggest you google genomics and proteomics. This relatively new field studies the expression of complexes of genes into their prospective proteins relative to the conditions the cells are under.