Can a Buddhist use antibacterial soap?

During my college humanities class, I learned some things about Buddhism, which I had not had exposure to before. My teacher would sometimes tell us stories about field trips he would take with the class to a local Buddhist temple. In one such story, he said that he asked the cute Buddhist that worked at the temple if Buddhists were allowed to use antibacterial soap. From his story, she apparently didn't find that very funny, but he was left without an answer. I understand that Buddhist's are not allowed to kill. Does this include microscopic living organisms that would be alive on your hands? In other words, what is the answer to his question, "Can Buddhists use anti-bacterial soap?"