Characterization of a new lytic bacteriophage (vB_KpnM_KP1) targeting Klebsiella pneumoniae strains associated with nosocomial infections.

A new bacteriophage, vB_KpnM_KP1, was identified and characterized, exhibiting a strong lytic effect on Klebsiella pneumoniae. Host range analysis revealed its effectiveness against 77.4% of clinical strains, achieving complete lysis of those associated with urinary tract infections (UTIs). Phage stability tests demonstrated that vB_KpnM_KP1 remained stable at neutral pH and across all tested temperatures. However, inactivation was observed at high ethanol concentrations and extreme pH levels. Transmission electron microscopy (TEM) analysis identified vB_KpnM_KP1 as a Myo-type phage with an icosahedral head and a contractile tail. Moreover, genome annotation of vB_KpnM_KP1 revealed a linear DNA genome of 174,802 bp, containing 307 open reading frames. Functional predictions suggest the presence of genes involved in DNA replication, transcription, morphogenesis, and cell lysis. Phylogenetic analysis classified vB_KpnM_KP1 within the Slopekvirus genus of the Straboviridae family, showing high sequence identity with phages that infect Enterobacter, Escherichia and Klebsiella species. These findings highlight the potential of phage vB_KpnM_KP1 as an alternative treatment for multidrug-resistant K. pneumoniae infections, particularly in UTIs, while offering valuable insights into its stability and genetic composition.