Gram-negative bacteremia induces greater magnitude of inflammatory response than Gram-positive bacteremia

Abstract

IntroductionBacteremia is recognized as a critical condition that influences the outcome of sepsis. Although large-scale surveillance studies of bacterial species causing bacteremia have been published, the pathophysiological differences in bacteremias with different causative bacterial species remain unclear. The objective of the present study is to investigate the differences in pathophysiology and the clinical course of bacteremia caused by different bacterial species.MethodsWe reviewed the medical records of all consecutive patients admitted to the general intensive care unit (ICU) of a university teaching hospital during the eight-year period since introduction of a rapid assay for interleukin (IL)-6 blood level to routine ICU practice in May 2000. White blood cell count, C-reactive protein (CRP), IL-6 blood level, and clinical course were compared among different pathogenic bacterial species.ResultsThe 259 eligible patients, as well as 515 eligible culture-positive blood samples collected from them, were included in this study. CRP, IL-6 blood level, and mortality were significantly higher in the septic shock group (n = 57) than in the sepsis group (n = 127) (P < 0.001). The 515 eligible culture-positive blood samples harbored a total of 593 isolates of microorganisms (Gram-positive, 407; Gram-negative, 176; fungi, 10). The incidence of Gram-negative bacteremia was significantly higher in the septic shock group than in the sepsis group (P < 0.001) and in the severe sepsis group (n = 75, P < 0.01). CRP and IL-6 blood level were significantly higher in Gram-negative bacteremia (n = 176) than in Gram-positive bacteremia (n = 407) (P < 0.001, <0.0005, respectively).ConclusionsThe incidence of Gram-negative bacteremia was significantly higher in bacteremic ICU patients with septic shock than in those with sepsis or severe sepsis. Furthermore, CRP and IL-6 levels were significantly higher in Gram-negative bacteremia than in Gram-positive bacteremia. These findings suggest that differences in host responses and virulence mechanisms of different pathogenic microorganisms should be considered in treatment of bacteremic patients, and that new countermeasures beyond conventional antimicrobial medications are urgently needed.

Bacteria and their cell wall components uniformly co-activate interleukin-17-producing thymocytes

“…These differences are not so pronounced with regard to IL-6, but Gram-negative bacteria also stimulate IL-6 production stronger than Gram-positive bacteria, which is in line with clinical observations in sepsis [25,26]. Therefore, it seems as if the composition of the bacterial cell wall essentially influences proinflammatory cytokine production in the thymus, but not the frequencies of IL-17 secreting cells.…”

Pathogen-Specific Local Immune Fingerprints Diagnose Bacterial Infection in Peritoneal Dialysis Patients

“…This will require a considerably larger cohort to determine whether responses to treatment in the culture-negative group can be further stratified and highlights the need for a more accurate cut-off value is determined by receiver operating characteristic analysis, and the statistical difference between the two curves is analyzed by the log-rank test. [24][25][26] there is no rapid diagnostic test that would guide treatment and allow predictive risk modeling at the time of presentation. Here, immune fingerprints in Gram-positive infections were markedly different from those in Gram-negative infections and were indicative of a relatively large underlying T cell component with higher numbers of CD4 + and CD8 + T cells and elevated levels of CXCL10, IFN-g, and IL-22.…”

“…[24][25][26] Our earlier findings indicated that elevated peritoneal frequencies of gd T cells within the total T cell population on the day of presentation were associated with subsequent technique failure. 20 Here, AUROC calculations identified Vd2 + T cell frequencies $4.3% as excellent discriminator that predicted short-term technique failure within the first 1-3 months (Figure 4), with an overall correctness of 94% at day 30 (4 of 48 patients with technique failure) and 77% at day 90 (9 of 48 patients) (Supplemental Tables 15-18).…”

Automated determination of neutrophil VCS parameters in diagnosis and treatment efficacy of neonatal sepsis

“…This may be associated with high cytokine production potential of Gram-negative microorganisms (17,18).…”