and frequently bacteria are involved in the process as they are used as a "delivery mechanism" for the genetic modifications.
Bacterial infections usually harm the host by the waste byproducts created by the bacteria or as a side effect of the body going to war against the invading organism.
Bacteria don't target DNA.
Viruses on the other hand are designed from the ground up to invade a cell and re-write the cell's genetic code in order to get the cell to stop its normal function and start churning out more copies of the virus.
Which is why re-coded viruses are used for genetic manipulation. We can take out the destructive payload of the virus and implant a new genetic sequence which will then be released into a body where it will invade cells and make the changes to the DNA.
For example if a person had a genetic inability to create a certain hormone or protein need for some function, you could insert a virus encoded with the corrected genetic code for that hormone or protein...thus fixing the problem.
Bacteria are not used in that manner.
Bacteria however *are* frequently used as the cells that get modified. Nova-log insulin is made by vats of bacteria that have been genetically re-encoded by viruses to produce the same insulin as our own pancreas does.
Not saying that it couldn't be a released bacteria or an escaped virus from Monsanto, just that Bacteria aren't used in the re-programming of genetic data.