Bacterial defense mechanisms against bacteriophages: an evolutionary arms race

Bacteria and bacteriophages are in a co-evolutionary arms race, developing intricate bacterial defense mechanisms that enable phage resistance and counterstrategies. Bacteria evolve diverse defense mechanisms to inhibit each stage of the phage infection cycle.Surface-based defenses prevent phage adsorption and infection, including receptor modifications, capsule production, and biofilm formation. Intracellular systems such as restriction-modification (R-M) and abortive infection (Abi) mechanisms degrade phage DNA or sacrifice infected cells to protect the population. Adaptive immunity, particularly through CRISPR-Cas systems, enables bacteria to recognize and neutralize recurring phage attacks. Phages counter…