I just read a report that describes the discovery of a new gene that, in bacteria, allows them to be resistant to just about all antibiotics and other medications we have in our biological arsenal. The gene, New Delhi metallo-beta-lactamase, or NDM-1,has been found in South Asia, and scientists are worried about the vast potential for bacteria with the gene to spread globally. International travel allows for this potential.
This is yet another good example of evolution in action. Bacteria, with their incredible exponential reproductive rates, multiply rapidly and, in some small percentage of cell divisions, have genetic mutations. Depending on which portion of the DNA mutates (i.e. which gene mutates), the mutated daughter bacteria can have new traits expressed in their phenotypes. Every so often, a mutated bacterium has a resistance to one of our drugs that will kill the previous type bacteria. As the older type are killed off by our drugs, the new mutant strains remain alive, and they then reproduce exponentially. Such change and variation is one of the prime actions in evolution. The rapid process that single-celled critters have for reproduction and genetic variation is why they were here long before humans existed, and why they will almost certainly be around long after humans are gone.
The new bacteria are presently most prevalent in India, Bangladesh, and Pakistan, and dozens of cases have been reported in Britain in patients who were recently treated in those Asian countries. We will see what becomes of this new threat in the weeks and months coming up.