Evaluating the Postoperative Timing of Rifampicin Introduction Linked to the Clinical and Microbiological Outcomes of Orthopedic Staphylococcal Implant Infections

Background/Objectives: In staphylococcal implant infections, there is often discussion about the optimal postoperative timing of the introduction of rifampicin in the postoperative period with open wounds. Methods: We reviewed all adult patients with residual staphylococcal implant infections between January 2014 and May 2024. We analyzed the delay to rifampicin use in relation to therapeutic failures, infection recurrences and development of ultimate rifampicin resistance. The “last Staphylococcus” represented any clinical sample at the end of the individual period. Results: Among 103 independent infection episodes, the pathogens were S. aureus in 47 episodes (46%) and the remainder were different coagulase-negative staphylococci. The median number of surgical interventions was 1 and the median duration of postsurgical systemic antibiotic treatment was 84 days (interquartile range (IQR), 42-84 d). The median daily dose of oral rifampicin was 900 mg, the median delay of its introduction 5 days (IQR, 3-8 d). Overall, 13% experienced an adverse event related to rifampicin (mostly gastrointestinal), requiring its stopping. The incidences of Clinical Failures and of Microbiologically identical Recurrences were 27% and 10%, respectively. The risk of rifampin-resistance among the “last Staphylococcus” isolates was 1%. This single case occurred in an infected knee to which rifampicin was introduced after a delay of eight days. In multivariate Cox regression analysis, the delay of rifampicin administration, its dose or its duration all failed to alter outcomes. Conclusions: In our retrospective cohort of staphylococcal orthopedic implant infections, the timing of rifampicin introduction failed to alter clinical and microbiological outcomes.