This article states it better than I can (though the article gets a bit into the scientific, but that's to be expected, considering the source):
"One of the foundations of the modern medical system is being similarly overcome. Health care workers are increasingly finding that nearly every weapon in their arsenal of more than 150 antibiotics is becoming useless. Bacteria that have survived attack by antibiotics have learned from the enemy and have grown stronger; some that have not had skirmishes themselves have learned from others that have. The result is a rising number of antibiotic-resistant strains. Infections - including tuberculosis, meningitis and pneumonia - that would once have been easily treated with an antibiotic are no longer so readily thwarted. More and more bacterial infections are proving deadly.
Bacteria are wily warriors, but even so, we have given them - and continue to give them - exactly what they need for their stunning success. By misusing and overusing antibiotics, we have encouraged super-races of bacteria to evolve. We don't finish a course of antibiotics. Or we use them for viral and other inappropriate infections - in fact, researchers estimate that one third to one half of all antibiotic prescriptions are unnecessary. We put 70 percent of the antibiotics we produce in the U.S. each year into our livestock. We add antibiotics to our dish washing liquid and our hand soap. In all these ways, we encourage the weak to die and the strong to become stronger see "The Challenge of Antibiotic Resistance," by Stuart B. Levy; Scientific American, March 1998].
It's all kind of scary. And next time you go to the grocery store, try and find some non-anti bacterial soap; it's distressing how impossible that is to do.