Management of biomaterial-associated infections: is it time for bacteriophages?

Current strategies to combat biomaterial-associated infections extensively employ the use of antibiotics. Due to increased rates of antibiotic-resistant strains of bacteria, search for other viable options is essential. Bacteriophages have been proposed as an alternative to commonly used antibiotics. One of potential advantages of bacteriophage-impregnated biomaterials is prevention of development of resistance. However, preserving stability of bacteriophages in biomaterial can be challenging. The purpose of this study was to determine changes in stability of bacteriophages impregnated in biomaterial films. The sample of study included Pseudomonas aeruginosa reference strain ATCC 27853, commercial bacteriophage cocktail produced by Microgen, Ltd. (Pyobacteriophag), stock solution of sodium alginate with aforementioned bacteriophage and bacteriophage-impregnated sodium alginate films. Phage suspension alone and in combination with sodium alginate were incubated at 37oC in dynamic conditions for different incubation periods. To display phage titer, the plaque assay was executed and stability of released bacteriophage from biomaterial was registered. All experiments were conducted in triplicate. Pyobacteriophag (Microgen, Ltd.) had an initial titer of 107 PFU/mL. By 48 hr of incubation, Pyobacteriophag stock alone demonstrated preserved titer of 107 PFU/mL. The indicated bacteriophage impregnated in sodium alginate films showed a three-fold reduction in titer (104 PFU/mL) after 8 hr of incubation with further lowering to a four-fold decrease (103 PFU/mL) after 48 hr. Conversely, there was no reduction in titer (107 PFU/mL) evident in stock solution of sodium alginate with bacteriophage. Data obtained indicates that there was no reduction in titer in suspension of Pyobacteriophag and stock solution of sodium alginate with bacteriophage. Contrarily, decline of titer of phage impregnated in sodium alginate films was observed. Maintaining stability of bacteriophage impregnated in biomaterial films and evaluation of bactericidal activity of it is of potential clinical interest for effective management of biomaterial-associated infections in both prophylactic and therapeutic interventions.