To control bacterial infections caused by widely spread and rapidly increasing multidrug-resistant and extensively drug-resistant bacterial strains, the bacteriophages and bacteriophage-derived antibacterial enzymes and proteins were considered. This is especially relevant to pathogens causing nosocomial infections, such as Acinetobacter baumannii, a gram-negative, non-fermenting aerobic microorganism, which over the years have acquired resistance to most of the currently available antibiotics and often associated with hospital pneumonia, the wound and urinary tract infections, post- surgery complications, and bloodstream infections.
Two novel viruses with lytic activity against clinical A. baumannii strains relating to the famous international clonal complexes have been isolated. According to transmission electron microscopy, the phages possess typical morphology of the family Podoviridae. Both phages demonstrated rapid adsorption to the bacterial hosts, short latent period and high burst size in one-step growth experiments.The phage linear double-stranded DNA (dsDNA) genomes of 41,642 bp and 41,402 bp, shared 86,3 % nucleotide sequence identity. A total of 49 and 51 putative protein-coding genes were predicted in the phage genomes. Products of predicted open reading frames of both phages include proteins involved in DNA replication and modification, transcription, DNA packaging into the capsid, phage structural and morphogenesis proteins, and proteins associated with bacterial cell lysis.
Comparative genomic analysis revealed similar genome organizations of the phages and high sequence similarity between DNAs of the phages and other known A. baumannii podophages except regions coding host receptor-binding proteins. It apparently indicated that phages could infect different strains within the species.
The newly isolated phages can be classified as members of the Autographivirinae subfamily, φKMV-like viruses subgroup on the basis of the position of phage encoding single-subunit viral RNA polymerase between the replication and structural gene clusters.

This work was supported by the Russian Science Foundation [Grant # 15-15-10017] and Ministry of Education and Science of the Russian Federation (Agreement No. 02.A03.21.0003).