Assessment of Phage-Mediated Inhibition and Removal of Multidrug-Resistant Pseudomonas aeruginosa Biofilm on Medical Implants

Purpose: Despite the growing interest in bacteriophage (phage) usage for the prevention, control, and removal of bacterial biofilms, few scientific data exist on phage applications on medical implant surfaces, while none exists on multiple implants. In this study, we aimed to isolate, biophysically characterize and assess phages as potential antibiofilm agents to inhibit and remove multidrug-resistant (MDR) Pseudomonas aeruginosa biofilm on catheter and endotracheal tube surfaces. Methods: The well-identified stored clinical isolates (n = 7) of MDR P. aeruginosa were obtained from Jimma Medical Center. Specific phages were isolated and characterized based on standard protocols. The phages were tested for their antibiofilm effects in preventing colonization and removing preformed biofilms of MDR P. aeruginosa, following phage coating and treatment of catheter and endotracheal tube segments. Results: Two P. aeruginosa-specific phages (Phi JHS-PA1139 and Phi SMK-PA1139) were isolated from JMC compound sewage sources. The phages were biophysically characterized as being thermally stable up to 40 degrees C and viable between pH 4.0 and 11.0. The two phages tested against clinical MDR strains of P. aeruginosa showed broad host ranges but not on other tested bacterial species. Both phages reduced MDR bacterial biofilms during the screening step. The phage-coated segments showed 1.2 log(10) up to 3.2 log(10) inhibition relative to non-coated segments following 6 h coating of segments prior to microbial load exposure. In both phages, 6 h treatment of the segments with 10(6) PFU/mL yielded 1.0 log(10) up to 1.6 log(10) reductions for VHS and 1.6 log(10) up to 2.4 log(10) reductions for Phi SMK. Conclusion: Our results suggest that phages have great potential to serve the dual purpose as surface coating agents for preventing MDR bacterial colonization in medical implants and as biofilm removal agents in implant-associated infections.