Complete Genome Sequence of Escherichia coli O157:H7–Specific Bacteriophage HME2 Isolated from Pond Water

Escherichia coli O157:H7 is a foodborne pathogen that causes severe symptoms such as hemorrhagic colitis and hemolytic uremic syndrome, posing a risk to human health through contaminated meat and fresh vegetables [1].Antibiotics are applied to reduce the proliferation of these bacteria, but there are persistent limitations due to the induction of antibiotic-resistant bacteria [2].Therefore, a novel strategy is required to overcome these disadvantages.Bacteriophages (phages) are alternative antibacterial agents that may reduce selective pressure associated with antibiotic use [3].Furthermore, their potential applications are increasing due to their high host specificity and superior lytic activity [3].Accordingly, this study presents a genomic analysis and functional identification of E. coli-infecting phage HME2.Phage HME2, isolated from a sewage pond in Hongcheon, Gangwon Province, Republic of Korea was tested using a plaque assay.Briefly, the pond water sample was combined with 2X Luria-Bertani broth (LB broth; MB Cell, Republic of Korea) at a 1:1 (v/v) ratio and incubated at 37℃ for 12 h with aeration.The mixture was centrifuged at 15,928 × g for 1 min at 4℃, and the resulting supernatant was filtered through a syringe filter with a pore size of 0.2 µm.The presence of the phage was confirmed using the double-layer agar technique.For phage purification, a single plaque was picked from the E. coli O157:H7 ATCC 43890 lawn and subjected to five consecutive rounds of plaque isolation.Phage genomic DNA was extracted using the phenolchloroform method.Whole-genome sequencing of phage HME2 was conducted by Macrogen Inc. (Republic of Korea) using the Illumina MiSeq platform with 151 bp paired-end reads.The sequencing run generated 21,789,540 reads, yielding a total of 3,290,220,240 bp.The average sequencing depth was 20,789×, calculated Bacteriophage HME2 targeting Escherichia coli O157:H7 was isolated from pond water.It has a 158,278 bp double-stranded DNA genome with a GC content of 44.5% and 115 predicted open reading frames.Genomic analysis confirmed its lysis-related genes and specific host-recognition determinants.Additionally, conserved functional domains within its tail fiber protein support its specific recognition of E. coli O157:H7.Orthologous average nucleotide identity values showed >95% similarity to other E. coli phages belonging to the genus Kuttervirus.