Prognostic value of endotoxemia in patients with Gram-negative bacteremia is bacterial species dependent.

The prognostic impact of endotoxemia detection in sepsis is unclear. Endotoxemia is detectable in <70% of patients with Gram-negative (GN) bacteremias. Mortality proportion data were available from 27 published studies of patients with GN bacteremia in various settings. Among ten studies restricted to specific types of GN bacteremia, endotoxemia was associated with significantly increased mortality risk for Neisseria meningitidis (4 studies; 138 bacteremias; OR 26.0; 95% CI, 1.6-321) but not for Salmonella enterica serovar Typhi (3 studies; 36 bacteremias; OR 0.89; 95% CI, 0.01-74.1). For 17 unrestricted studies (319 GN bacteremic patients), endotoxemia was associated with an increased mortality risk with non-Escherichia coli Enterobacteriaceae such as Klebsiella and Enterobacter species (97 bacteremias; OR 3.7; 95% CI, 1.3-10.3). By contrast, E. coli (144 bacteremias; OR 0.78; 95% CI, 0.36-1.7), and non-Enterobacteriaceae species such as Pseudomonas species (78 bacteremias; OR 1.7; 95% CI, 0.7-4.6) had no increased mortality risk. That endotoxemia detection is predictive of mortality among patients bacteremic with non-E. coli Enterobacteriaceae but not E. coli is surprising given the presumed commonality of the hexa-acyl lipid A structure among Enterobacteriaceae species.