MRSA infections were all in the group of rifampicin and all achieved remission; therefore, this difference cannot explain the difference between the 2 groups. In addition, it is not possible to rule out a low linezolid concentration in the rifampicin group as an additional explanation. Linezolid is a time-dependent antibiotic [24]; therefore, the pharmacodynamic target is to maintain a trough serum concentration around 2 times over the minimum inhibitory concentration (MIC). Since the MIC90 for Gram-positive staphylococci is 2 mg/L

[25], the optimal trough level will be 4 mg/L, a concentration that also it has been associated with low risk of toxicity [26], which is the major concern when linezolid is administered for prolonged time. These results suggest that monitoring trough serum concentration could be useful for improving the outcome, most especially when linezolid is combined with rifampicin, and for avoiding toxicity in patients that require prolonged SAHA HDAC price mTOR inhibitor treatment [27]. Indeed, hematological toxicity was more frequent in the monotherapy group (24% vs. 5%) probably due to the higher linezolid concentrations. The main drawbacks of this study are the low number of patients, the retrospective design, that clonal relationship between microorganism isolated in primary and relapse episodes was not performed in order to confirm the relapse rate and the fact that linezolid concentrations were not measured;

however, the information reported is useful to improve the results in PJIs due to resistant staphylococci. Conclusion Acute PJIs managed with debridement and retention of the implant linezolid, with or without rifampicin, are associated with a high remission rate and this is therefore an alternative therapy for infections due to fluoroquinolone and/or rifampicin-resistant staphylococci. However, prolonged linezolid may have Vasopressin Receptor important AEs that require close monitoring by infectious diseases physicians. Acknowledgments Sponsorship for this study was funded by Pfizer (Madrid, Spain) and Fundación Privada Máximo Soriano Jiménez (Barcelona, Spain). All named authors meet the ICMJE Erastin purchase criteria for authorship for

this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval for the version to be published. Conflict of interest A. Soriano has received honoraria for public speaking and from advisory boards of Pfizer and Novartis. J. Mensa has received honoraria for public speaking and from advisory boards of Pfizer and Novartis. E. Senneville has received honoraria for public speaking and from advisory boards of Sanofi-Aventis, Pfizer and Novartis. L. Bernard has received honoraria for public speaking and from advisory boards of Pfizer and Astellas. L. Morata, S. Nguyen, R. Buzele, J. Druon and E. Tornero declare no conflicts of interest. Compliance with ethics guidelines This study was approved by the Ethics Committee of our institution.