Systems of Phage Resistance in <I>Vibrio cholerae</I> Strains

Abstract

The aim of the review is to analyze the literature data on systems of resistance to lytic cholera phages in Vibrio cholerae strains. Cholera phages are both present in the water of open reservoirs and isolated together with the pathogen from cholera patients. The mechanisms of molecular protection of V. cholerae from phages are similar to these systems of other bacteria, act at all stages of phage infection and include the following stages: prevention of phage adsorption, degradation of phage nucleic acids and inhibition of the formation of phage particles. Blocking the interaction of a phage with a bacterial cell occurs as a result of modification of receptors and the production of extracellular polysaccharides that create a physical barrier between the phages and the cell surface. If the phage DNA does enter the cells, it is destroyed by restriction-modification enzymes, as well as by the adaptive immune system CRISPR-Cas. The most numerous are the mechanisms for blocking the formation of phage particles in cells. This process occurs with the participation of phage-inducible PLE islands, the BREX bacteriophage exclusion system and abortive Abi infection, including the cyclic oligonucleotide-based anti-phage signaling system (CBASS) and the toxin-antitoxin system. During Abi infection, cells infected with the phage self-destruct and die before mature phage particles are formed, which contributes to the preservation of the V. cholerae population. The molecular mechanisms of a number of anti-phage systems have not yet been fully elucidated, which indicates the need for further study of the phage-host relations.