Does Rifampin (R) use before reimplatation in patients treated with two-stage replacement for prosthetic joint infection (PJI) increase the risk of positive culture with R-resistant Gram-Positive Cocci?

Background: R has been shown of great interest for the treatment of PJI due to Gram-positive cocci (GPC), especially staphylococci. Data on risk factors of positive culture due to R-resistant GCP at reimplantation in patients treated with two-sage replacement for PJI are scarce. Methods: Medical charts of patients followed in a French referent center for osteo-articular infection over a 13-year period (1999 to 2012) were reviewed. Every patient was treated by a two-stage revision surgery procedure with antibiotic-loaded spacer (gentamycin or gentamycin + vancomycin) between the two stages. R combinations were started only when the definitive microbiological results were available, following empirical broad-spectrum antibiotic therapy. Demographic data were collected from each patient as well as details regarding surgery. We reviewed each GPC during the first and the second stage and compared the susceptibility profile of each strain to rifampin. Results: A total of 125 evaluable patients of mean age 78 years with PJIs including THA (63%) and TKP (37%) were included for analysis. The mean delay between first and second stage was 84 days with an average duration of antibiotic therapy of 62 days. R-combinations were used in 71 (56.8%) patients. At reimplantation, intra-operative cultures were negative in 67% of the patients. No variable was significantly associated with the emergence of R-resistant GPC at reimplantation, including the use of R combinations (9/71 vs 8/54, respectively P=0.73). Conclusions: The results of the present study suggest that R combinations administered properly (ie after surgery and in combinations selected on the basis of intra-operative sample culture results) do not increase the risk of positive culture at reimplantation due to R-resistant GPC and therefore can be used safely between removal and reimplantation of the prosthesis in patients treated with two-stage replacement for PJI