Oral antibiotic therapy for the treatment of infective endocarditis: a systematic review

Background: The role of oral antibiotic therapy in treating infective endocarditis (IE) is not well established. Methods: We searched MEDLINE, EMBASE and Scopus for studies in which oral antibiotic therapy was used for the treatment of IE. Results: Seven observational studies evaluating the use oral beta-lactams (five), oral ciprofloxacin in combination with rifampin (one), and linezolid (one) for the treatment of IE caused by susceptible bacteria reported cure rates between 77% and 100%. Two other observational studies using aureomycin or sulfonamide, however, had failure rates > 75%. One clinical trial comparing oral amoxicillin versus intravenous ceftriaxone for streptococcal IE reported 100% cure in both arms but its reporting had serious methodological limitations. One small clinical trial (n = 85) comparing oral ciprofloxacin and rifampin versus conventional intravenous antibiotic therapy for uncomplicated right-sided S. aureus IE in intravenous drug users (IVDUs) reported cure rates of 89% and 90% in each arm, respectively (P = 0.9); however, drug toxicities were more common in the latter group (62% versus 3%; P < 0.01). Major limitations of this trial were lack of allocation concealment and blinding at the delivery of the study drug(s) and assessment of outcomes. Conclusion: Reported cure rates for IE treated with oral antibiotic regimens vary widely. The use of oral ciprofloxacin in combination with rifampin for uncomplicated right-sided S. aureus IE in IVDUs is supported by one small clinical trial of relatively good quality and could be considered when conventional IV antibiotic therapy is not possible.