 So, as far as researchers currently know, anti-CRISPR is the most effective way to ensure the survival of phages throughout the infection process of bacteria.Anti-CRISPR systems were first seen in "Pseudomonas aeruginosa" prophages, which disabled type I-F CRISPR–Cas system, characteristic of some strains of these bacteria.After analysing the genomic sequences of these phages, genes codifying five different Anti-CRISPR proteins (also named Acrs) were discovered.