Seven-versus 14-day course of antibiotics for the treatment of bloodstream infections by Enterobacterales: a randomized, controlled trial

To prove that 7-day courses of antibiotics for bloodstream infections caused by members of the Enterobacterales (eBSIs) allow a reduction in patients' exposure to antibiotics while achieving clinical outcomes similar to those of 14-day schemes. A randomized trial was performed. Adult patients developing eBSI with appropriate source control were assigned to 7 or 14 days of treatment, and followed 28 days after treatment cessation; treatments could be resumed whenever necessary. The primary endpoint was days of treatment at the end of follow-up. Clinical outcomes included clinical cure, relapse of eBSI and relapse of fever. A superiority margin of 3 days was set for the primary endpoint, and a non-inferiority margin of 10% was set for clinical outcomes. Efficacy and safety were assessed together with a DOOR/RADAR (desirability of outcome ranking and response adjusted for duration of antibiotic risk) analysis. 248 patients were assigned to 7 (n = 119) or 14 (n = 129) days of treatment. In the intention-to-treat analysis, median days of treatment at the end of follow-up were 7 and 14 days (difference 7, 95%CI 7–7). The non-inferiority margin was also met for clinical outcomes, except for relapse of fever (–0.2%, 95%CI –10.4 to 10.1). The DOOR/RADAR showed that 7-day schemes had a 77.7% probability of achieving better results than 14-day treatments. 7-day schemes allowed a reduction in antibiotic exposure of patients with eBSI while achieving outcomes similar to those of 14-day schemes. The possibility of relapsing fever in a limited number of patients, without relevance to final outcomes, may not be excluded, but was overcome by the benefits of shortening treatments.