An Infection Machine (IMAGE) Yale University Caption This is a surface rendering of the structure of type III secretion needle complex, which is used by Salmonella to infect cells. Credit Thomas Marlovits/Courtesy of Yale University Usage Restrictions None 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.