Oral Antibiotic Therapy Liaison: Patrick O’Toole MD Leaders: Douglas Osmon MD (US), Alex Soriano DO (International) Delegates: Jan-Erik Berdal MD, Mathias Bostrum, Rafael Franco-Cendejas MD, DeYoung Huang PhD, Charles Nelson, F Nishisaka, Brian Roslund, Cassandra D Salgado, Robert Sawyer MD, John Segreti MD, Eric Senneville PhD, Xian Long Zhang Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/jor.22560 ß 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:S152–S157, 2014. Introduction This panel has reviewed the indication and duration of oral antibiotics for periprosthetic joint infection (PJI) in the following situations: (1) Acute (early or late) PJI treated with debridement without implant removal and exchange of the modular components, whenever modular compo- nents can be safely removed. In general, these infections do not require suppressive antibiotic therapy (SAT). (2) Indications for the use of SAT include: (a) Patients who refuse surgical treatment. (b) Patients who cannot be surgically treated be- cause of a high surgical risk due to comorbidities. (c) Patients treated with inadequate surgery such as: (1) debridement without implant re- moval in late chronic PJI or (2) debridement without implant removal in acute (early or late) PJI but without exchanging the modular components. (d) Patients who undergo optimal surgical treat- ment in acute PJI but receive suboptimal antibiotic treatment in the following situations: (1) not receiving rifampin in PJI due to Staphy- lococcus spp, (2) PJI due to methicillin-resis- tant S. aureus (MRSA), (3) not receiving a fluoroquinolone in gram-negative infections, and (4) fungal infections. (e) Patients in whom it is suspected that the infection is not eradicated according to clinical, laboratory, or imaging data. Question 1: What are the appropriate oral antibiotic or antibiotic combinations following adequate surgical treatment for acute (early or late) PJI in which the implant has been retained? Consensus Regimens containing rifampicin, when feasible, should be used in gram-positive PJI and fluoroquinolones in gram-negative PJI. There is no consensus as to when rifampicin should be started. Delegate Vote Agree: 87%, Disagree: 7%, Abstain: 6% (Strong Con- sensus) Justification In acute PJI, open debridement and implant retention is associated with a wide variation in success rates. Once the decision to switch to oral therapy is made, a combination of antibiotics should be used. The reasons for this discrepancy include: (1) characteristics of the patients, (2) surgical technique including the exchange of modular polyethylene liner, and (3) the type of antibiotic or combination of antibiotics administered, especially within the first month after debridement. 1,2 There is concern with the use of rifampin during the first days of intravenous (IV) treatment in order to reduce the risk of selecting resistant mutants. 3 Staph- ylococcus aureus and coagulase-negative staphylococ- cus for the most part is best treated with combination therapy. In terms of antibiotic treatment, it is necessary to analyze the results according to the isolated microor- ganism. A review of the published literature where staphylococci were the main pathogen included 17 articles and 525 cases of PJI managed with open debridement and retention of the implant. The study showed a range of success from 14% to 83% with a mean rate of success of 48% 4 and only 32% in patients with rheumatoid arthritis. 5 A more recent review of the literature using Debridement, Antibiotics, and Implant Retention (DAIR), described a success rate below 50%. 6 Of note, the majority of the articles included in these reviews did not use rifampin as part of the antibiotic treatment. In contrast, intravenous vancomycin or b-lactams for the first 4 weeks were the most common antibiotic therapies. In vitro data and experimental models on foreign-body infections have shown the poor activity of these antibiotics against bacterial biofilms and the importance of combining antibiotics, preferentially with rifampin. 7–12 Zimmerli et al. performed a double-blind study and found that acute staphylococcal orthopaedic implant infections treated with an open debridement without removing the implant, followed by a combination of ciprofloxacin (750 mg/12 h) and rifampin (450 mg/12 h) administered for 3 months (for hip prosthesis and orthopaedic implant infections) or 6 months (for knee prosthesis infections), was more effective than ciprofloxacin alone (cure rates of 100% and of 53%, respectively, p < 0.05 after 35 months of follow-up). From 2005 up to now other case series have been published using antibiotic S152 JOURNAL OF ORTHOPAEDIC RESEARCH JANUARY 2014