Study Of The Effect Of Pulsed Washing On Antibiotic Susceptibility Of MRSA Biofilms.
(2019) 20th EFORT Congress (European Federation of National Associations of Orthopaedics and Traumatology) — Location: (Portugal) Lisbon (5.June.2019)
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- Background Pulsed washing (PW) is a major step during debridement surgery in the context of orthopaedic device-related infections (ODRI), but its effects on biofilms are poorly understood. Previous studies showed a weak effect of PW alone or combined with antiseptics on MRSA biofilms in-vitro. The combined effect of PW and antibiotics has never been published in the orthopaedic literature. Objectives The present study aims at evaluating the effect of PW alone or followed by vancomycin treatment on MRSA biofilms grown on titanium Ti6Al4V coupons in-vitro. Study Design & Methods MRSA strains: ATCC33591 and clinical isolates 25755749 and 27353676 (isolates from ODRI). Biofilm culture: Ti6Al4V coupons were incubated during 24h at 37°C with a bacterial suspension (starting inoculum ~6.6Log10CFU/mL in TGN [TSB + 1% glucose + 2% NaCl], under shaking at 50rpm. Treatment: Half of the coupons received PW with 50mL of physiological serum using a Stryker Interpulse from a distance of 5cm; the coupons were then either analysed or reincubated for 24h in TGN or TGN + vancomycin at two concentrations (MIC and a therapeutic concentration of 20µg/mL). Analysis: Coupons were rinsed twice with PBS. Total biomass was determined by crystal violet (CV) staining. CFUs were counted after recovering bacteria from coupons (alternating vortexing and sonication) and TSA plating. Results For control biofilms, 24h reincubation without or with vancomycin had no influence on CFU counts or total biomass, except for a minor biomass decrease in isolate 27353676 at 20µg/mL of vancomycin. For biofilms exposed to PW, a significant reduction in both CFU (2.58-3.12log10) and biomass (77.81-96.15%) was observed, but full regrowth was observed after 24 h reincubation in control conditions. Reincubation with vancomycin prevented regrowth when used at its MIC but further reduced CFUs at 20 µg/mL in a synergistic way. Conclusions PW alone only has a transient effect on coupon colonisation by MRSA biofilms and vancomycin alone at therapeutic concentrations is largely ineffective. Yet, in combination, these treatments show synergistic effects. These results suggest the importance of thorough washing during debridement procedures. However, completeness of PW in-vivo is limited by poor access to parts of the implants due to anatomical constraints, providing arguments for the development of alternative strategies to disrupt biofilms.
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Poilvache, H., Cornu, O., & Van Bambeke, F. (2019). Study Of The Effect Of Pulsed Washing On Antibiotic Susceptibility Of MRSA Biofilms. 20th EFORT Congress (European Federation of National Associations of Orthopaedics and Traumatology), (Portugal) Lisbon. https://hdl.handle.net/2078.5/271933