From the novel potential biomarkers, only PCT demonstrated superiority over the routine parameters in the differentiation of bacterial from viral infections. However, some of the novel parameters should be further evaluated in larger and better characterized cohorts of patients in order to find their clinical applications.

Our results indicate that Gram-positive sepsis causes stronger suppression of peripheral blood lymphocyte subsets in comparison to sepsis due to Gram-negative pathogens.

AbstractThe implementation of new markers of bacterial infection into clinical practice is hindered by their costs. We assessed the potential use of the neutrophil to lymphocyte count ratio (NLCR) to discriminate between bacterial and viral infections. NLCR was evaluated in 45 patients with bacterial infections: 24 patients with viral infections and 18 healthy adults. The medians of NLCR were 11.73 in bacterial infections, 2.86 in viral infections and 1.86 in controls. The NLCR cut-off value of 6.2 exhibited a sensitivity value of 0.91 and a specificity value of 0.96 for bacterial infection. These results suggest a diagnostic potential for NLCR.

Routinely used biomarkers of bacterial etiology of infection, such as C-reactive protein and procalcitonin, have limited usefulness for evaluation of infections since their expression is enhanced by a number of different conditions. Therefore, several inflammatory cytokines and chemokines were analyzed with sera from patients hospitalized for moderate bacterial and viral infectious diseases. In total, 57 subjects were enrolled: 21 patients with community-acquired bacterial infections, 26 patients with viral infections, and 10 healthy subjects (control cohorts). The laboratory analyses were performed using Luminex technology, and the following molecules were examined: IL-1Ra, IL-2, IL-4, IL-6, IL-8, TNF-α, INF-γ, MIP-1β, and MCP-1. Bacterial etiology of infection was associated with significantly (P < 0.001) elevated serum concentrations of IL-1Ra, IL-2, IL-6, and TNF-α in comparison to levels observed in the sera of patients with viral infections. In the patients with bacterial infections, IL-1Ra and IL-8 demonstrated positive correlation with C-reactive protein, whereas, IL-1Ra, TNF-α, and MCP-1 correlated with procalcitonin. Furthermore, elevated levels of IL-1Ra, IL-6, and TNF-α decreased within 3 days of antibiotic therapy to levels observed in control subjects. The results show IL-1Ra as a potential useful biomarker of community-acquired bacterial infection.