Background: Methicillin-resistant Staphylococcus aureus bloodstream infections carry a high risk of morbidity and relapse with most published guidelines recommending prolonged courses of IV antibiotics to ensure complete clearance of the infection. However, long-term IV antibiotic therapy may also be costly and is not without its own complications. An equally effective IV-to-oral antibiotic therapy would be welcome.
Study design: Retrospective cohort study.
Setting: A single academic center in the United States.
Synopsis: The investigators reviewed data from 492 adults with at least one positive blood culture for MRSA who had not yet completed their antibiotic course at the time of discharge during the index hospitalization but were sufficiently stable to complete outpatient antibiotic treatment. Of this cohort, 70 patients were switched to oral antibiotic therapy on discharge, while the rest received OPAT. The primary outcome was clinical failure, a 90-day composite measure of MRSA bloodstream infection recurrence, deep MRSA infection, or all-cause mortality. The most commonly used oral antibiotics were linezolid, trimethoprim/sulfamethoxazole, and clindamycin, all with high bioavailability. Endovascular infection was present in 21.5% of the study population. After propensity score adjustment for covariates, patients who received oral antibiotics had a nonsignificant reduction in the rate of clinical failure (hazard ratio, 0.379; 95% CI, 0.131-1.101).
Limitations of the study included its observational design with potential for significant residual confounding despite the propensity score–adjusted analysis, its single-center setting, the low frequency of endovascular infections, and the uncertainty in how the loss of patients to follow-up might have affected the results.
Bottom line: Selected patients with MRSA BSI may be successfully treated with sequential IV-to-oral antibiotic therapy.
Citation: Jorgensen SCJ et al. Sequential intravenous-to-oral outpatient antibiotic therapy for MRSA bacteraemia: One step closer..
Dr. Torres is a hospitalist at Massachusetts General Hospital.