The adherence of Proteus mirabilis to the surface of
urinary catheters leads to colonization and eventual blockage of the
catheter lumen by unique crystalline biofilms produced by these opportunistic pathogens, making P. mirabilis one of the leading causes of
catheter-associated
urinary tract infections. The Proteus biofilms reduce efficiency of
antibiotic-based treatment, which in turn increases the risk of antibiotic resistance development. Bacteriophages and their
enzymes have recently become investigated as alternative treatment options. In this study, a novel Proteus bacteriophage (vB_PmiS_PM-CJR) was isolated from an environmental sample and fully characterized. The phage displayed depolymerase activity and the subsequent genome analysis revealed the presence of a
pectate lyase domain in its tail spike
protein. The
protein was heterologously expressed and purified; the ability of the purified tail spike to degrade Proteus biofilms was tested. We showed that the application of the tail spike
protein was able to reduce the adherence of bacterial biofilm to
plastic pegs in a MBEC (minimum biofilm eradication concentration) assay and improve the survival of Galleria mellonella larvae infected with Proteus mirabilis. Our study is the first to successfully isolate and characterize a biofilm depolymerase from a Proteus phage, demonstrating the potential of this group of
enzymes in treatment of
Proteus infections.