There was a 97.8% probability that 7 days of antibiotics was noninferior to 14 days for treating Gram-negative bloodstream infections, according to a recent review.

In a systematic review and Bayesian meta-analysis, investigators assessed whether a 7-day course of antibiotics was noninferior to a 14-day course for treating Gram-negative bloodstream infections. In the analysis, published in JAMA Network Open, the investigators included data from four randomized clinical trials (RCT) comprising 3,729 hospitalized adult patients with a median age range of 67 to 79 years. Among the participants, 51.3% were women. Most infections were caused by Enterobacterales bacteria.

Lead study author Todd C. Lee, MD, MPH, of the Division of Infectious Diseases in the Department of Medicine at McGill University in Montreal, and colleagues conducted a literature search of PubMed, Cochrane Central Register of Controlled Trials, and Web of Science to identify RCTs between May 2022 and November 2024. Studies included adult patients hospitalized with Gram-negative bacteremia who were randomly assigned to receive either 7 or 14 days of antibiotic therapy. Treatment duration was not blinded. Outcomes were analyzed using both intention-to-treat (ITT) and per-protocol (PP) populations. Bayesian random-effects meta-analyses were performed using a noninformative prior-for-treatment effect and a weakly informative prior for heterogeneity. Noninferiority was prespecified as a risk ratio (RR) of 1.25 or less for 90-day all-cause mortality.

In the ITT analysis (n = 3,729), mortality occurred in 12.8% of the patients in the 7-day group compared with 13.7% of those in the 14-day group. This corresponded to an RR of 0.91 (95% credible interval [CrI] = 0.69–1.22) and a 97.8% probability of noninferiority. In the PP population (n = 3,126), mortality occurred in 179 of 1,527 patients in the 7-day group and 199 of 1,599 patients in the 14-day group, resulting in a risk ratio of 0.93 (95% CrI = 0.68–1.32) and a 95.1% probability of noninferiority.

The probability of superiority (RR < 1.00) was 76.6% in the ITT and 68.9% in the PP populations. The certainty of evidence was rated high using GRADE criteria. The investigators concluded that a 7-day antibiotic regimen is likely noninferior to 14 days for Gram-negative bloodstream infections in patients with adequate source control, supporting shorter treatment durations in appropriate clinical scenarios.

Full disclosures can be found in the published review.