Recently, Associate Professor Liming Jiang of School of Basic Medical Sciences, Ningbo University School of Medicine, as the first author, has made a new progress in host bacterial tolerance to phage infection. The results are presented as “Growth stage-related capsular polysaccharide translocon Wza in Vibrio splendidus modifies phage vB_VspM_VS2 susceptibility (Vibrio splendidus growth stage-related capsular polysaccharide translocon Wza modulates phage vB_VspM_VS2 susceptibility) Wza in Vibrio splendidus modifies phage vB_VspM_VS2 susceptibility (Vibrio splendidus growth phase-associated podoplanar polysaccharide Wza modulates phage vB_VspM_VS2 susceptibility)” was published in Communications Biology, a prestigious CAS double-region journal of Biology, which is a member of the Nature Publishing Group (IF:5.2).

As the problem of antibiotic-resistant bacteria worsens, there is an urgent need for phages and phage-derived products (e.g. lysozyme) to replace antibiotic drugs. The infection cycle of phage begins by adsorbing bacterial receptors, followed by injection of nucleic acids into bacteria, DNA replication, biosynthesis of structural proteins, assembly and release. Notably, the survival of phages depends on their ability to infect susceptible bacteria, and the key step in phage lysis of host bacteria is the phage adsorption phase, which involves the binding of the phage to the bacterial surface receptor, which determines the host specificity of the phage.

This study identifies a robust anti-phage defense mechanism in Vibrio vulnificus and investigates the anti-phage infection properties in different growth stages and phage-infected states. Bacteria in the stable growth or early exponential phase of phage infection exhibited down-regulation of luxR and wza, resulting in reduced susceptibility to phage and making individual cells nearly impervious to phage infection. In contrast, in bacteria in the early exponential phase, wza expression was unaffected and individual bacteria were completely susceptible to infection. The results of this study suggest that Wza in Vibrio can promote phage infection by regulating phage uptake, which provides important implications for the use of phage therapy to target pathogenic bacteria in dynamic flora.

Ningbo University is the first completion unit of this thesis, and this study was supported by the National Natural Science Foundation of China, the Natural Science Foundation of Zhejiang Province, and the Ningbo Yongjiang Talent Introduction Program.