Mark Coventry Award: Efficacy of Saline Wash Plus Antibiotics Doped Polyvinyl Alcohol (PVA) Composite (PVA-VAN/TOB-P) in a Mouse Pouch Infection Model.

Abstract

The efficacy of saline irrigation for treatment of periprosthetic infection (PJI) is limited by the presence of contaminated medical devices. This study evaluated treatment efficacy of locally placed polyvinyl alcohol (PVA)/bioceramic composite doped with vancomycin (PVA-VAN-P) or vancomycin and tobramycin (PVA-VAN/TOB-P) after saline irrigation in a mouse pouch infection model. Sutures were implanted into air pouches of BALB/cJ mice, then inoculated with Staphylococcus aureus. Mice were randomized into 6 groups (n= 6 each): (1) no bacteria; (2) bacteria without saline wash; (3) saline wash only; (4) saline wash+ PVA-P; (5) saline wash+ PVA-VAN-P, and (6) saline wash+ PVA-VAN/TOB-P. After 7 days, pouches were washed with saline alone or with additional injection of 0.2 mL of the composites. Sacrifice occurred 14 days after the washout. Histology was performed on the pouch tissues and bacteria cultures on the washout fluid. Bacterial culture (optical density) showed that infection persisted after saline irrigation (0.10±0.14) but was effectively eradicated by the addition of PVA-VAN-P (0.05±0.09) and PVA-VAN/TOB-P (0.002±0.003, P < .05). These effects were confirmed by histology. Importantly, no residues of the PVA-P were detected in either the pouch washouts or pouch tissues. PJI is common and problematic, and few innovations have changed clinical practice and/or outcome. Our data confirmed that the effect of saline irrigation was very limited in the presence of contaminated sutures. PVA-VAN/TOB-P was biodegradable, biocompatible, and effective in eradicating bacterial retention after saline irrigation. Application of PVA-VAN/TOB-P after saline irrigation could be an option for treatment of PJI and should be evaluated in future PJI animal models.