Abstract: This study aimed to provide different methods for solving drug-resistant Pseudomonas aeruginosa infections. P. aeruginosa phage was isolated and purified from hospital wastewater using chicken-derived P. aeruginosa as host bacteria, and biological characterization and genomic analysis were performed, while its effect was tested using a checkerboard method in combination with three antibiotics. The results showed that a strain of P. aeruginosa phage PaVOB was isolated from hospital wastewater, TEM showed that virus particles had an icosahedral head with an average diameter of 73.02 nm and a long tail with an average length of 155.57 nm, it belongs to the family Siphoviridae in the order Caudovirales, had a double-stranded DNA genome, had a narrow host spectrum, was resistant to low temperatures (-20 ℃) and reached the optimal temperature at 37 ℃, had good acid-base tolerance, and maintained activity at pH 3-12, the optimal MOI is 0.001, the one-step growth curve shows that the latent period is 10 min, the outbreak amount is 50 PFU·cell^-1, and the adsorption test shows that the adsorption rate of PaVOB at 10 min is 99.1%. The full length of PaVOB genome was 72 179 bp, (G+C)% content was 54.81%, with VB PaeP FBPa1 The affinity was less than 0.1. ORF prediction showed that PaVOB included 74 ORFs, and none of the software predictions revealed the presence of virulence genes, drug resistance genes and tRNAs. In addition, the results of antibiotic combination showed that PaVOB had synergistic effect with ceftriaxone, had synergistic effect with enrofloxacin at potency of 10⁷ PFU·mL^-1, and had unrelated effect with gentamicin. P. aeruginosa phage PaVOB is highly adaptable to the environment and has clear genomic information, which can be selectively applied in combination with different antibiotics to exert synergistic effects and has the possibility of treating clinically resistant Pseudomonas aeruginosa.

Key words: Pseudomonas aeruginosa, phage, biological properties, genomics, antibiotic combination