Biological characterization and complete genome analysis of a novel Stenotrophomonas maltophilia phage vB_SM_ytsc_ply2008005c.

Multidrug-resistant bacteria have become a major threat to global public health. Bacteriophages are regarded as a promising substitute. Here, we present a novel lytic Stenotrophomonas maltophilia phage, vB_SM_ytsc_ply2008005c, which was isolated from sewage water samples in Qingdao, east China. Virion morphology of phage particles indicated that ply2008005c has an icosahedral head (56 ± 5 nm in diameter) and a noncontractile sheathed tail (129 ± 6 nm in length), which are the typical characteristics of phages belonging to the family Siphoviridae. Phage ply2008005c could be used for phage therapy for its stability in a wide pH (4 to 12) range and high temperature (up to 70°C) environment. Genome analysis revealed that ply2008005c has a circular double-strand DNA of 42,318 bp with a G+C content of 63.02%. It shared the closest relationship with phage vB_PaeS_PAO1_Ab18, but the homology coverage is just 20%. There were 54 open reading frames predicted in its genome, including three unique proteins and 34 functional genes in different modules. The phylogenetic analysis revealed that ply2008005c forms a distinct branch of the family Siphoviridae. These results demonstrated that ply2008005c was supposed to be a representative new member within the family Siphoviridae, which could be considered a potential bioagent against multidrug-resistant S. maltophilia.