Legionella (IMAGE) University of Vienna Caption The pathogen Legionella (colored in pink) preferably multiplies in amoebae (light blue). These unicellular organisms measure approximately 50 μm in diameter and often harbor bacterial endosymbionts (green), which inhibit the growth of Legionella. This is how they protect amoebae and contribute to reducing the spread of Legionella in the environment. Credit © Cecilia Wentrup Usage Restrictions The image may only be used with appropriate caption or 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.