Tom Luthe, Larissa Kever, Kai Thormann, Julia Frunzke

Multicellular behaviour benefits seemingly simple organisms such as bacteria, by improving nutrient uptake, resistance to stresses or by providing advantages in predatory interactions. Several recent studies have shown that this also extends to the defense against bacteriophages, which are omnipresent in almost all habitats. In this review, we summarize strategies conferring protection against phage infection at the multicellular level, covering secretion of small antiphage molecules or membrane vesicles, the role of quorum sensing in phage defense, and the impact of biofilm components and architecture. Recent studies focusing on these topics push the boundaries of our understanding of the bacterial immune system and set the ground for an appreciation of bacterial multicellular behaviour in antiviral defense.