Forget what Mom said about cleanliness being next to godliness. A little dirt, and the bacteria that are in it, is actually critical to human health.

The rise of anti-bacterial soaps in households and the quickness with which physicians prescribe antibiotics are serious threats to health, according to Dr. Michael Hudson, the dean of the biology department at the University of North Carolina Charlotte. Dr. Hudson goes so far as to say that failing to throw away antibacterial soap can cause death, according to a recently distributed press release.

Dr. Hudson’s special area of study is Staphylococcus aureus. In his lab and at home, he uses Ivory soap, not any of the anti-bacterial soaps that fill grocery store shelves. People’s bodies are teeming with various bacteria, and many perform essential roles. In fact, according to the press release, people are composed of about 1 trillion human cells, but they are hosts to 100 trillion bacteria cells.

“Most of the 100 trillion are not capable of causing disease,” Dr. Hudson says in the release. “They compete with each other. They keep each other in check.” The problem with using anti-bacterial soap and the misuse of antibiotics is that they upset the balance between good and bad bacteria. The bacteria that can kill survive the soap and become strong and resistant to treatment.

Dr. Hudson doesn’t dismiss concern about bacteria. His lab has a sample of community acquired methicillin-resistant Staphylococcus aureus, also known as CA-MRSA, which the Centers for Disease Control and Prevention estimates kills 19,000 in the U.S. each year.

“There is nothing left to treat it,” Dr. Hudson said in a recent radio appearance. “The worst problem facing humans on the planet is anti-bacterial resistance, because we’ll be back to the 1930s. Pretty soon treatment will be amputation.”

In this age of HIV-AIDS, SARS, mad cow disease, avian flu and whatever disease that splashes across the front page next, people naturally want to protect themselves by eradicating microbial intruders.

Understanding how the bacteria become problems should help guide a more appropriate response. Human skin constantly provides itself with a coating of oil. Bacteria adhere to the oily skin, and then can be transferred to the eye, mouth, nose and ear. So rather than treat skin surfaces to a harsh take-no-prisoners scouring, the key is to wash away the oil and with it the bacteria.

To stay healthy, Dr. Hudson recommends frequent hand washing with hot water and regular soap; avoidance of “broad spectrum” antibiotics; if prescribed antibiotics, always take the full course; wash any cuts aggressively with soap and water; if water is not available, alcohol-based sanitizers will suffice; and use lotions to avoid having cracked skin where bacteria can penetrate.