Bacteriophage vs. Bacterium (IMAGE) Michigan Medicine - University of Michigan Caption An ongoing battle between viruses and bacteria in the gut help keep things in balance. Credit Stephanie King Usage Restrictions with credit to Stephanie King 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.