Isolation and characterization of biofilm-disrupting proteus phage Premi

Proteus mirabilis is a biofilm-forming, multidrug-resistant bacterium and one of the most common causes of catheter-associated urinary tract infections (CAUTIs). Phage therapy is an alternative method that can be used to address the problem of multidrug-resistance. In this study, we report isolation and characterization of virulent phage Premi. The phage exhibits lytic activity against 4 out of 30 clinical isolates of P. mirabilis tested and is stable when exposed to pH values between 3 and 11. Phage Premi demonstrated significant anti-biofilm activity against P. mirabilis, reducing 24-hour established biofilms by 59-68%. In the 42-kb Premi genome, functions were assigned for the 50 predicted protein-coding genes including those involved in DNA replication, DNA modification, and lysis. Structural proteins were verified using mass spectrometry of purified virions. A comparison of its genomic features and phylogenetic analysis revealed that phage Premi is a podophage member of the order Caudoviricetes sharing 96% nucleotide similarity with Proteus phage PM 85 and has a T7-like phage genomic organization. Our study shows that Premi effectively inhibits P. mirabilis biofilms and could be a promising antimicrobial agent for treating drug-resistant P. mirabilis infection.