Novel Phage-Derived Depolymerase with Activity against Proteus mirabilis Biofilms

Abstract

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.

Isolation and Characterization of Lytic Proteus Virus 309

“…No significant differences (p < 0.05) were recorded in PFU/mL from 20 to 50 °C. Reduced titers of Proteus phages vB_PmiS-TH and vB_PmiS_PM-CJR were recorded after exposure to 70 °C [46,54], with complete inactivation at 80 °C. Proteus_virus_309 remained infective at pH values ranging from 5 to 11 (Figure 3B), with no significant difference observed across the range (p < 0.05).…”

Evolutionary Dynamics between Phages and Bacteria as a Possible Approach for Designing Effective Phage Therapies against Antibiotic-Resistant Bacteria

“…The phage-encoding enzymes are classified into lyases and hydrolases based on the cleavage of polysaccharides [ 59 ]. A tail spike protein of the Proteus bacteriophage (PmiS_PM-CJR) encodes pectate lyase to degrade the biofilm matrix [ 140 ]. Similarly, a tail protein of the phage IME200 degrades the capsule polysaccharide, in Acenetobacter baumanni [ 141 ].…”

DePolymerase Predictor (DePP): a machine learning tool for the targeted identification of phage depolymerases

“…The therapeutic potential of phage DPs was recognised more than 60 years ago [ 12 ]. Phage DPs are of particular interest due to their potential use in combinatorial therapies with antibiotics or other antimicrobial agents and in the removal of biofilms from medical devices most notably catheters [ 13 , 14 ]. Moreover, as the depolymerases do not kill bacteria, it is posited that they could be employed on their own as anti-virulence agents, decreasing bacterial fitness and facilitating the clearance of the bacteria by the human immune system [ 10 ].…”