Bacteria are in public generally considered dangerous and the source of different diseases. Since the discovery of bacteria by Antonie van Leeuwenhoek, most efforts have been focused on killing bacterial cells in order to get rid of different infections. The reality, however, most bacterial species do not cause any disease. In contrast, our health is dependent on many types of bacteria: the ones that are living inside our body and forming the microbiota, and the ones making food, drugs, and vaccines, like small factories. We are living in a sort of symbiosis with these small creatures.