Prevention of Aortic Graft Infections Using Therapeutic Bacteriophages

Background: Aortic graft infections are a major complication in cardiothoracic surgery leading to a significantly increased mortality. The spreading of multi- or pan-resistant bacteria makes it necessary to develop new strategies to prevent and fight those prosthetic graft infections. Bacteriophages are an effective alternative tool to antibiotics. In our study we evaluated the possibility of a phage based prevention of vascular graft infections.

Method: Small unified pieces of woven PET gelatinized aortic grafts were used to model a prosthetic infection in vitro. The graft samples were inoculated with the most common bacterial pathogens. Staphylococcus aureus and Escherichia coli were chosen as an example of gram-positive and gram-negative bacteria respectively. Inoculated with bacterial suspensions, experimental samples were impregnated with antibacterial solutions or coated with a fibrin glue containing antibiotics, phages, or their combinations. The samples were incubated for 24 hours followed by CFU counts on the surface, SEM of the samples, and OD600 measurement of the culture medium.

Results: A statistically significant difference between control and experimental samples was observed in all groups by OD600 measurement and in all samples coated with fibrin glue by counting of CFU. Combination of antibiotics and bacteriophages with fibrin glue coating showed lowest values of OD600 and counts of CFU for both tested species of bacteria.

Conclusion: In this in vitro study, the bacteriophages presented themselves as a promising approach for the prevention of vascular graft infections. Taking into account existence of broad range staphylococcal and coliphages, prevention of these infections can be performed both individually after phage sensitivity testing (e.g., in case of re-surgery) or potentially empirically as a cocktail of most clinically relevant strains of bacteriophages. However, tests of phages against target bacteria are mandatory for almost all infections caused by other bacterial pathogens due to narrow host range activity of known bacteriophages.

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Artikel online veröffentlicht:
03. Februar 2022