Solutions of Siderophores (IMAGE) Washington University in St. Louis Caption Rainbow of colors is created by different concentrations of siderophores, molecules secreted by bacteria to steal iron from a host during an infection. Credit Shangwen Luo/ University of Illinois at Chicago Usage Restrictions Please credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.