Triclosan Shown to Trigger Resistance in Aquatic Ecosystems

A widely used compound to prevent bacterial contamination is persisting in the environment and creating antibacterial resistant strains of bacteria.


That is the conclusion of a study by researchers at the Illinois Sustainable Technology Center (ISTC) in Champaign, IL, Loyola University Chicago, and the Cary institute of Ecosystem Studies in Millbrook, NY. The study was published in Environmental Science and Technology a journal of the American Chemical Society.


Triclosan is a broad-spectrum anti-microbial compound used in a large variety of consumer products from soap to cosmetics to clothing. The Food and Drug Administration approved the substance and after reports of possible side effects, recently reviewed their own findings, announcing that there is not enough evidence to determine the substance is hazardous.
Meanwhile Proctor and Gamble announced recently they are phasing out the use of Triclosan in its products.


John Scott, ISTC’s senior chemist, was co-Principal Investigator with Loyola Biology Professor John J. Kelly in the research which confirmed the presence of Triclosan in stream sediment in the Chicago metropolitan region. Sources for Triclosan contamination includes domestic wastewater, traced to broken sewer pipes and releases of untreated wastewater during high rainfall events.


First they conducted field surveys which indicated Triclosan concentrations increased in more highly urbanized areas. They found a significant correlation between the concentration of Triclosan on the stream bottom and Triclosan-resistant bacteria present. Controlled experiments in an artificial stream confirmed the compound triggers resistance and shifts the diversity and composition of bacterial communities. The consequences of altered bacterial communities have not been determined.



Sphingobacteria is one type most impacted for community composition by Triclosan.