COMPARISON AMONG PRESEPSIN, PROCALCITONIN, AND C-REACTIVE PROTEIN IN PREDICTING BLOOD CULTURE POSITIVITY AND PATHOGEN IN SEPSIS PATIENTS.

Background: Sepsis is caused by the invasion of the bloodstream by microorganisms from local sites of infection, leading to high mortality. This study aimed to compare the predictive ability of the biomarkers presepsin, procalcitonin (PCT), and C-reactive protein for bacteraemia. Methods: In this retrospective, multicentre study, a dataset of patients with sepsis who were prospectively enrolled between November 2017 and June 2021 was analyzed. The performances of the biomarkers for predicting positive blood cultures and infection with specific pathogens were assessed by the areas under the receiver operating characteristic curves (AUCs). The independent effects of the pathogen and foci of infection on presepsin and PCT levels were assessed by linear logistic regression models. Results: A total of 577 patients with 170 positive blood cultures (29.5%) were enrolled. The AUC achieved using PCT levels (0.856) was significantly higher than that achieved using presepsin (0.786, P = 0.0200) and C-reactive protein (0.550, P < 0.0001) levels in predicting bacteraemia. The combined analysis of PCT and presepsin levels led to a significantly higher AUC than the analysis of PCT levels alone for predicting blood culture positivity (0.877 vs. 0.856, P = 0.0344) and gram-negative bacteraemia (0.900 vs. 0.875, P = 0.0216). In a linear regression model, the elevated concentrations of presepsin and PCT were both independently related to Escherichia coli , Klebsiella species, Pseudomonas species, and Streptococcus species infections and Sequential Organ Failure Assessment score. Presepsin levels were also associated with Acinetobacter species and abdominal infection, and PCT levels were positively associated with other Enterobacteriaceae and negatively associated with respiratory infection. Combined analysis of presepsin and PCT levels provided a high sensitivity and specificity in identifying E. coli or Klebsiella species infection. Conclusions: Presepsin and PCT were promising markers for predicting bacteraemia and common pathogens at the time of sepsis onset with a synergistic effect.