Abstract
Bacteria are under constant attack from bacteriophages (phages), bacterial parasites that are the most abundant biological entity on earth. To resist phage infection, bacteria have evolved an impressive arsenal of anti-phage systems. Recent advances have significantly broadened and deepened our understanding of how bacteria battle phages, spearheaded by new systems like CRISPR-Cas. This review aims to summarize bacterial anti-phage mechanisms, with an emphasis on the most recent developments in the field.