Sonostandard: Sonication for implant-associated infections: A Swiss consensus protocol

Sonication of explanted implants has improved microbiological detection in implant-associated infections. However, large inter-laboratory variability in sonication protocols limits comparability and clinical interpretability. A national consensus-driven initiative was launched to standardize the diagnostic sonication process, using current Swiss practice and the published evidence as a foundation.

An evidence-informed structured consensus process was conducted, including a national protocol survey and a scoping review of published sonication workflows. An online consensus meeting followed, with structured item-by-item discussion and a single round of anonymous voting per item (consensus: ≥80% agreement among valid votes).

Twenty-one laboratories participated; four without sonication and one duplicate response was identified. Consensus was reached in 8 of 9 domains: sonication frequency (40 kHz, 100%), intensity (100% device output, 100%), temperature (room temperature, 100%), duration (1 min, 90.5%), fluid (Ringer's solution, 95.5%), pre- and post-sonication vortexing (30 s each, 94.4%), processing within 6 h (87.5%), culture media panel (aerobic blood agar 93.8%, chocolate agar +5% CO₂ 100%, thioglycolate broth 100%, anaerobic Schaedler agar 93.3%), incubation (14 days, 84.6%), and quantitative reporting (CFU/mL, 100%). Neither volume standardization proposal reached consensus: weight-based volume achieved 33.3% and minimum volume rule 43.8%, reflecting ongoing feasibility and implementation concerns.

A national consensus protocol was developed to harmonize sonication-based implant microbiology processing across key technical, handling, culture, incubation, and reporting domains, while volume standardization remained open due to operational constraints. This framework is intended to facilitate inter-laboratory comparability, with future work focused on implementation evaluation and evidence-based interpretive thresholds.