Early oral switch in low-risk Staphylococcus aureus bloodstream infection

Background Staphylococcus aureus bloodstream infection (SAB) is treated with at least 14 days of intravenously administered antimicrobials. We assessed the efficacy and safety of an early oral switch therapy in patients at low risk for SAB-related complications. Methods In an international non-inferiority trial, we randomized patients with SAB after 5 to 7 days of intravenous antimicrobial therapy to either switch to an oral antimicrobial or to continue with intravenous standard therapy. Main exclusion criteria were signs and symptoms of complicated SAB, non-removable foreign devices, and severe comorbidity. Composite primary endpoint was the occurrence of any SAB-related complication (relapsing SAB, deep-seated infection, and mortality attributable to SAB) within 90 days. Results 213 patients were randomized into the intention-to-treat population. In the oral switch group, 14/108 (13%) participants reached the primary endpoint versus 13/105 (12%) in the standard therapy group (adjusted difference 0.7%, 95% confidence interval [CI] -7.8% to 9.1%). Participants in the oral switch group were discharged earlier (median hospital stay from SAB onset of 12 days versus 16 days; adjusted difference -3.1 days [95% CI -7.5 to 1.4]). There was no statistical difference in 30-day survival and complications of intravenous administration. More participants in the oral group experienced at least one serious adverse event (34% versus 26%, p=0.292). Conclusion Oral switch was non-inferior to intravenous standard therapy in participants with low-risk SAB. However, a careful assessment of patients for signs and symptoms of complicated SAB at time of presentation and thereafter is necessary before considering early oral switch therapy. The trial was registered as NCT01792804 in ClinicalTrials.gov, as DRKS00004741 in the German Clinical trials register, and as EudraCT 2013-000577-77.