Isolation and Characterization of vB_kpnM_17-11, a Novel Phage Efficient Against Carbapenem-Resistant Klebsiella pneumoniae

Abstract

Phages and phage-encoded proteins exhibit promising prospects in the treatment of Carbapenem-Resistant <i>Klebsiella pneumoniae</i> (CRKP) infections. In this study, a novel <i>Klebsiella pneumoniae</i> phage vB_kpnM_17-11 was isolated and identified by using a CRKP host. vB_kpnM_17-11 has an icosahedral head and a retractable tail. The latent and exponential phases were 30 and 60 minutes, respectively; the burst size was 31.7 PFU/cell and the optimal MOI was 0.001. vB_kpnM_17-11 remained stable in a wide range of pH (4-8) and temperature (4-40°C). The genome of vB_kpnM_17-11 is 165,894 bp, double-stranded DNA (dsDNA), containing 275 Open Reading Frames (ORFs). It belongs to the family of <i>Myoviridae</i>, order Caudovirales, and has a close evolutionary relationship with <i>Klebsiella</i> phage PKO111. Sequence analysis showed that the 4530 bp <i>orf022</i> of vB_kpnM_17-11 encodes a putative depolymerase. <i>In vitro</i> testing demonstrated that vB_kpnM_17-11 can decrease the number of <i>K. pneumoniae</i> by 10⁵-fold. In a mouse model of infection, phage administration improved survival and reduced the number of <i>K. pneumoniae</i> in the abdominal cavity by 10⁴-fold. In conclusion, vB_kpnM_17-11 showed excellent <i>in vitro</i> and <i>in vivo</i> performance against <i>K. pneumoniae</i> infection and constitutes a promising candidate for the development of phage therapy against CRKP.