isolation and characterization of a novel escherichia coli o157:h7-specific phage as a biocontrol agent

Escherichia coli o157:h7 is one of the major foodborne pathogens of global public concern. bacteriophages (phages) have emerged as a promising alternative to antibiotics for controlling pathogenic bacteria. here, a lytic e. coli o157:h7-specific phage (kfs-ec) was isolated, identified, and characterized to evaluate its potential as a biocontrol agent for e. coli o157:h7. kfs-ec was isolated from slaughterhouse in korea. morphological analysis, genomic analysis and several physiological tests were performed to identify and characterize the kfs-ec. a specificity test indicated kfs-ec was strictly specific to e. coli o157:h7 strains among 60 bacterial strains tested. morphological and phylogenetic analyses confirmed that kfs-ec belongs to the rb49virus genus, tevenvirinae subfamily, and the myoviridae family of phages. kfs-ec genome consists of 164,725 bp and a total of 270 coding sequence features, of which 114 open reading frames (orfs) were identified as phage functional genes. kfs-ec does not contain genes encoding lysogenic property and pathogenicity, which ensure its safe application. kfs-ec was relatively stable (~1 log decrease) under stressed conditions such as temperatures (20 °c–50 °c), phs (3–11), organic solvents (ethanol and chloroform), and biocides (0.1% citric acid, 1% citric acid, and 0.1% peracetic acid). kfs-ec was able to inhibit e. coli o157:h7 efficiently at a multiplicity of infection (moi) of 0.01 for 8 h with greater inhibitory effect and durability and was stable at 4 °c and 22 °c over a 12-week storage period. our results suggest that kfs-ec could be used as a biocontrol agent to e. coli o157:h7.