Breaking the matrix: Novel phages disrupt resilient Pseudomonas aeruginosa biofilms and enhance chemical disinfection on ICU surfaces

Hospital surfaces, particularly in intensive care units (ICUs), often harbor Pseudomonas aeruginosa , a notorious, opportunistic pathogen capable of surviving on fomite surfaces and forming highly resilient biofilms, presenting a significant infection control challenge. To address this, our study investigates bacteriophages as a targeted disinfection strategy, focusing on the isolation and characterization of four novel phages-AM.P2, AM.P3, AM.P4 and AM.P5 for their potential to eradicate biofilms on fomites from ICU settings. Genomic analysis revealed all the phages to be novel, dsDNA phages, lacking AMR and virulence genes. AM.P3 and AM.P5 are jumbo phages (280.1Kb and 279.9Kb, respectively), in contrast to AM.P4 (73.2Kb), which was similar to AM.P2. All phages exhibited robust physicochemical stability over a wide range of temperatures and pH (4 °C- 60 °C; pH:4-10). The disinfection potential of the phages on planktonic bacteria, evaluated on steel and tile surfaces from ICU settings, demonstrated significant inhibition potential (80%-98% and 81%-100% respectively). Additionally, all the phages and phage cocktail also exhibited significant inhibition of biofilm formation (67%-79%), as well as disruption of established mature biofilms (43%-70%) on steel surfaces. Furthermore, a comparative study with two commonly used chemical disinfectants in ICUs, demonstrated that sequential treatment with phage, followed by disinfectant, resulted in enhanced disruption of mature biofilm on fomite surfaces from ICUs, as compared to phage or disinfectant individually, highlighting an effective translational approach for the use of phages to enhance the efficacy of disinfectants. • Isolation of phages targeting Pseudomonas aeruginosa devoid of AMR and virulence genes from sewage treatment plants • Effective surface decontamination achieved using phage-based formulations. • Enhanced disinfection efficiency through sequential phage–disinfectant application. • This combinatorial approach is efficacious and sustainable on ICU-fomite surfaces.