25dkou299 10.3205/25dkou299 urn:nbn:de:0183-25dkou2994 Meeting Abstract Nessler Nessler Vincent Benedict VB

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Bertheloot Bertheloot Damien D

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Assaf Assaf Elio E

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Amerschläger Amerschläger Cosmea C

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Ossendorff Ossendorff Robert R

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Jaenisch Jaenisch Max M

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Strauss Strauss Andreas A

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Walmsley Walmsley Phillip J. PJ

University of St Andrews School of Medicine, St. Andrews, UK

author Hischebeth Hischebeth Gunnar Thorben Rembert GTR

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Wirtz Wirtz Dieter C. DC

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author Hammond Hammond Robert J. H. RJH

University of St Andrews School of Medicine, St. Andrews, UK

author Schildberg Schildberg Frank Alexander FA

Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Bonn, Bonn, Deutschland

author German Medical Science GMS Publishing House

Düsseldorf

610 20251031 engl This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). M0634 299 Deutsche Gesellschaft für Orthopädie und Unfallchirurgie Deutsche Gesellschaft für Orthopädie und Orthopädische Chirurgie Deutsche Gesellschaft für Unfallchirurgie Berufsverband für Orthopädie und Unfallchirurgie Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2025) Grundlagenforschung | Infekt & Diagnostik 1 Berlin 20251028 20251031 AB44-4529 TextObjectives and questions: Bacterial antibiotic resistance is a key challenge and constant battle in modern medicine. Current methods to identify infective microbes and define antibiotic susceptibilities are culture based and thus require two to ten days. This prolonged diagnostic delays targeted treatment and potentially impacts patient outcome. In this exploratory prospective study, we strived to establish a faster sensitive method to characterize antibiotic activity against bacterial growth in patient material, using a Scattered Light Integrated Collector (SLIC). Material and methods: SLIC detects refraction of light beamed through a particulate-containing solution. Bacteria in solution refract light and can be recorded in real-time with yet unmatched sensitivity (102 CFU/mL). As recently published, SLIC can monitor growth of bacteria isolated from patient material and its inhibition by antibiotics. We tailored antibiotic panels to determine the class of infective microbe and clinically relevant susceptibilities. In this follow-up study, we optimized our method for direct use of primary peri-operative synovial fluid and tissue from periprosthetic joint infection (PJI) patients. We implemented enzymatic and chemical treatments of these complex primary samples to reduce time to positivity for detection of microbial growth, without affecting the activity of our selected antibiotics. Finally, we tested our antibiotic panels (that cover most clinically used classes, allow MRSA- and MRGN-classification and classification of the virulent microbe) against PJI primary samples.Results: As we have published, SLIC can accurately and reproducibly measure dose-dependent inhibitory or bacteriolytic antibiotic effects and thus provide an antibiotic susceptibility profile of an isolated and pre-cultured bacterium within 90 minutes. In the current follow-up study, we were able to transfer our findings to primary samples. We show that SLIC can reliably differentiate infected from uninfected samples within a few hours, allowing real-time detection of an infection without the need for prior microbial isolation and culture. Time to positivity could be further reduced by enzymatic and chemical pre-treatment. Strikingly, we could monitor antibiotic activity reliably and accurately in both infected joint fluid and periprosthetic tissue, rapidly providing antibiogram-like data.Discussion and conclusions: This new approach could accelerate diagnostic procedures by avoiding the need for isolation and culture of the infecting microbe. The battle against multi-resistant bacteria calls for faster reliable means of diagnosis to reduce untargeted empirical antibiosis and thus improve patient outcome. Our SLIC-based method presents a strong option to target both of these aspects, delivering reliable antibiotic susceptibility statements in far shorter time than current microbiology standards. 0 0 0 0