By Mackenzie Bean

The use of consumer products that contain the chemical triclosan is fueling antibiotic resistance, according to a study published in Antimicrobial Agents and Chemotherapy.

Triclosan is the active ingredient in many products marketed to have antibacterial properties, such as toothpaste, mouthwash and cosmetics.

For the study, researchers at Washington University in St. Louis examined whether triclosan could protect bacteria from antibiotics designed to kill bacterial cells. Researchers monitored bacterial cells' survival after exposure to antibiotics. In one test, researchers exposed the bacteria to triclosan before administering antibiotics.

"Triclosan increased the number of surviving bacterial cells substantially," said study author Petra Levin, PhD, a professor of biology at Washington University. "Normally, one in a million cells survive antibiotics, and a functioning immune system can control them. But triclosan was shifting the number of cells. Instead of only one in a million bacteria surviving, one in 10 organisms survived after 20 hours."

Due to these unintended consequences, researchers concluded there is an urgent need to re-evaluate the costs and benefits of the using triclosan in consumer products.