Screening of genes involved in phage-resistance of Escherichia coli and effects of substances interacting with primosomal protein a on the resistant bacteria

ABSTRACT Aims The study was to identify the genes involved in phage resistance and to develop an effective biocontrol method to improve the lytic activity of phages against foodborne pathogens. Methods and results 3 909 single gene-deletion mutants of Escherichia coli BW25113 from the Keio collection were individually screened for genes involved in phage resistance. Phage S127BCL3 isolated from chicken liver, infecting both E. coli BW25113 and O157: H7 was characterized and used for screening. 10 gene-deletion mutants showed increased susceptibility to phage S127BCL3. Among them, priA gene-deletion mutant strain showed significant susceptibility to the phage S127BCL3 and T7. Furthermore, we investigated the substances, which have been reported to inhibit the function of primosomal protein A (PriA), were used to confirm increased phage susceptibility in E. coli BW25113 (Parent strain) and O157: H7. Conclusion PriA inhibitors at a low concentration showed combined effects with phage against E. coli O157: H7 and delayed the regrowth rate of phage-resistant cells. Significance and Impact Phage resistance is a major hurdle in phage therapy. 10 genes were identified for phage resistance. These findings suggest that the synergistic effects of the substances that inhibiting the function of PriA and phages provide a basis of a promising biocontrol tool.