<em>Mycobacterium vaccae</em> (IMAGE) University of Colorado at Boulder Caption Immunization with this friendly bacteria has been found to create a more stress-resilient environment in the brain. Credit CU Boulder 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.