Development of Clinically Relevant Methods to Predict the Efficacy of Phage Therapy for Surgical Infections after Cardiovascular Surgery

Background: Surgical site infections remain a significant concern in cardiovascular surgery, particularly when they involve multidrug-resistant pathogens. Phages are an effective alternative or supplement to antibiotic therapy. Currently, retrospective cases of bacteriophage use in cardiovascular surgery have been described. However, there is no systematization of the obtained data, which complicates the development of the evidence base. This study aims to develop practical and clinically applicable methods to predict the effectiveness of bacteriophage therapy in the context of surgical site infections following cardiovascular procedures. These methods are essential for optimizing treatment strategies, enhancing patient outcomes and establishing evidence-based guidelines for the utilization of bacteriophages in cardiac and vascular surgery.

Methods: To simulate the local situation in treated tissues, we developed variants of gelatin-based scaffolds with controlled nutrient composition. The first scaffold variant, based on 12% type B gelatin with added nutrient medium, was developed to simulate the proteolytic activity of bacteria and to evaluate the protective effect of phages at different concentrations. S. aureus and P. aeruginosa were used as bacteria with known proteolytic activity. The second type of scaffold, based on solidified type B gelatin, was designed to evaluate the adhesion rate of bacteriophages to the surface of the treated area.

Results: Using the first scaffold variant, we obtained a stable dose-dependent protective effect with staphylococcal bacteriophage. In the study with P. aeruginosa phage, the protective effect was observed only during the first day, regardless of the phage concentration. Using the second scaffold variant, the efficiency of bacteriophage adhesion was evaluated as a function of exposure time and also as a function of the presence of bacterial contamination.

Conclusion: The methods developed enable the optimization of phage therapy regimens. This is an important prerequisite for personalizing treatment and strengthening the evidence base for the use of bacteriophages in the treatment of surgical infections in cardiovascular surgery. Such systematization of therapy lays a foundation for the design of a prospective randomized controlled trial.

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Artikel online veröffentlicht:
13. Februar 2024