Leping Wang 1,2 , Yizhou Tan 1,2, Yuying Liao 3, Lei Li 1,2, Kaiou Han 1,2, Huili Bai 3, Yajie Cao 1,2, Jun Li 3,Yu Gong 4, XiaoyeWang 1,2,* and Hao Peng 3,*

Vet. Sci. 2022, 9, 675. https://doi.org/10.3390/vetsci9120675

Abstract: Escherichia coli (O78) is an avian pathogenic Escherichia coli (APEC). It can cause perihepatitis,pericarditis, septicemia and even systemic infections in the poultry industry. With the incidence of antibiotic resistance reaching a crisis point, it is important to find alternative treatments for multidrugresistant infections. The use of phages to control pathogens is a promising therapeutic option for antibiotic replacement. In this study, we isolated a lytic phage called vB_EcoS_GN06 from sewage. It lysed APEC GXEC-N22. Transmission electron microscopy showed that the phage belongs to family Siphoviridae. Phage GN06 has a 107,237 bp linear double-stranded DNA genome with 39.2% GC content and 155 coding sequences. It belongs to the genus Tequintavirus, subfamily Markadamsvirinae.The multiplicity of infection of 0.01 and the one-step growth showed that the latent time is 60 min and the burst size is 434 PFU/cell. Temperature and pH stability tests showed that phage GN06 was stable in the range of 4 _C–60 _C and pH 5–9. GN06 showed significant inhibition of APEC both within the liquid medium and in biofilm formation. These results suggest that phage GN06 has the potential to control bacterial pathogens. Thus, GN06 has the potential to be a new potential candidate for phage therapy.

Keywords: phage; avian pathogenic Escherichia coli; whole genome analysis