Effect of Poloxamer 407-Vancomycin Compounds on In Vitro Biofilms: A Pilot Study

Introduction: The purpose of this study is to measure the effect of a poloxamer gel-vancomycin compound on in vitro multidrug resistant (MDR) biofilms.

Materials and Methods: A clinical isolate of MDR E. faecium was grown on polycarbonate coupons for 72 hours at 37°C. The biofilms were treated with 25% P-407 gel + 20 mg/mL vancomycin (PV) or 25% P-407 gel alone (P) for 0 (no treatment), 4, 8, 12, 16, 20, 26, and 48 hours. Biofilms were stained with SYBR green and then were imaged using a Leica confocal scanning laser microscope (CSLM) at ×10 magnification. Biofilm thickness and 3D morphology were recorded.

Results: Biofilms in the PV group decreased in thickness, developed holes, and dispersed bacteria onto the underlying plate over time. Additionally, there was a significant difference in thickness of the biofilm in the PV group at time points 8, 12, 16, 24, 36, and 48 hours. There was no significant difference in biofilm thickness over time in the P group. Over time, the PV group biofilms flattened out in 3D reconstruction and the P group biofilms did not.

Discussion/Conclusion: Poloxamer 407-vancomycin gel significantly decreased biofilm thickness and density within 24 hours of application, matching the results noted in clinical patients. A larger time-course study is warranted.

Acknowledgment: This project was funded in part by a Mississippi State University College of Veterinary Medicine Office of Research and Graduate Studies House Officer Grant (2018–2019).