Therapeutic effect of Pseudomonas aeruginosa phage YH30 on mink hemorrhagic pneumonia

• Phage YH30 was isolated using the mink-originating P. aeruginosa as a host.
• YH30 meets the main prerequisites for a candidate therapeutic phage.
• YH30 can cure hemorrhagic pneumonia caused by P. aeruginosa in mink.

Hemorrhagic pneumonia caused by Pseudomonas aeruginosa remains one of the most costly infectious diseases among farmed mink and commonly leads to large economic losses during mink production. The objective of this study was to investigate the potential of using phages as a therapy against hemorrhagic pneumonia in mink. A broad-host-range phage from the Podoviridae family, YH30, was isolated using the mink-originating P. aeruginosa (serotype G) D7 strain as a host. The genome of YH30 was 72,192 bp (54.92% G + C), contained 86 open reading frames and lacked regions encoding known virulence factors, integration-related proteins or antibiotic resistance determinants. These characteristics make YH30 eligible for use in phage therapy. The results of a curative treatment experiment demonstrated that a single intranasal administration of YH30 was sufficient to cure hemorrhagic pneumonia in mink. The mean colony count of P. aeruginosa in the blood and lung of YH30-protected mink was less than 103 CFU/mL (g) within 24 h of bacterial challenge and ultimately became undetectable, whereas that in unprotected mink reached more than 108 CFU/mL (g). Additionally, YH30 dramatically improved the pathological manifestations of lung injury in mink with hemorrhagic pneumonia. Our work demonstrates the potential of phages to treat P. aeruginosa-caused hemorrhagic pneumonia in mink.