BackgroundPublic hospitals in emerging countries pose a challenge to quality improvement initiatives in sepsis. Our objective was to evaluate the results of a quality improvement initiative in sepsis in a network of public institutions and to assess potential differences between institutions that did or did not achieve a reduction in mortality.MethodsWe conducted a prospective study of patients with sepsis or septic shock. We collected baseline data on compliance with the Surviving Sepsis Campaign 6-h bundles and mortality. Afterward, we initiated a multifaceted quality improvement initiative for patients with sepsis or septic shock in all hospital sectors. The primary outcome was hospital mortality over time. The secondary outcomes were the time to sepsis diagnosis and compliance with the entire 6-h bundles throughout the intervention. We defined successful institutions as those where the mortality rates decreased significantly over time, using a logistic regression model. We analyzed differences over time in the secondary outcomes by comparing the successful institutions with the nonsuccessful ones. We assessed the predictors of in-hospital mortality using logistic regression models. All tests were two-sided, and a p value less than 0.05 indicated statistical significance.ResultsWe included 3435 patients from the emergency departments (50.7%), wards (34.1%), and intensive care units (15.2%) of 9 institutions. Throughout the intervention, there was an overall reduction in the risk of death, in the proportion of septic shock, and the time to sepsis diagnosis, as well as an improvement in compliance with the 6-h bundle. The time to sepsis diagnosis, but not the compliance with bundles, was associated with a reduction in the risk of death. However, there was a significant reduction in mortality in only two institutions. The reduction in the time to sepsis diagnosis was greater in the successful institutions. By contrast, the nonsuccessful sites had a greater increase in compliance with the 6-h bundle.ConclusionsQuality improvement initiatives reduced sepsis mortality in public Brazilian institutions, although not in all of them. Early recognition seems to be a more relevant factor than compliance with the 6-h bundle.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-017-1858-z) contains supplementary material, which is available to authorized users.