Abstract: Objective  To explore the relationship between serum levels of procalcitonin (PCT), endotoxin and C-reactive protein (CRP) and pathogens and prognosis in sepsis patients.  Methods  A total of 74 sepsis patients confirmed by positive blood culture between January 2020 and January 2021 were retrospective analyzed. According to blood culture results, they were divided into Gram-negative bacteria group (n=46) and Gram-positive bacteria group (n=28); according to the prognosis at the 28th day after hospitalization, they were divided into survival group (n=55) and death group (n=19). The serum levels of PCT, endotoxin and CRP were compared between Gram-negative bacteria group and Gram-positive bacteria group as well as between survival group and death group. Spearman correlation analysis was used to analyze the correlation between serum levels of PCT, endotoxin and CRP and bacterial pathogens in sepsis patients. The receiver operating characteristic curve (ROC curve) was used to explore the value of serum levels of PCT, endotoxin and CRP for prognosis prediction in sepsis patients.  Results  The serum levels of PCT, endotoxin and CRP were 3.79±0.57ng/ml, 0.60±0.13ng/L and 36.35±4.59mg/L respectively in Gram-negative bacteria group, significantly higher than those of 1.72±0.46ng/ml, 0.18±0.04ng/L and 18.42±3.14mg/L respectively in Gram-positive bacteria group (t=16.251, 16.585 and 18.215 respectively; P<0.001). The mortality rate was 34.78% in Gram-negative bacteria group, higher than that of 10.71% in Gram-positive bacteria group (χ2=5.284, P=0.022). The serum levels of PCT, endotoxin and CRP were (3.41±0.74)ng/ml, (0.55±0.12)ng/L and (35.76±7.21)mg/L respectively in death group, higher than those of (2.34±0.59)ng/ml, (0.38±0.11)ng/L and (27.41±5.08)mg/L respectively in survival group (t=6.374, 5.674 and 5.517 respectively; P<0.001). Spearman correlation analysis showed that the serum levels of PCT, endotoxin and CRP in sepsis patients were negatively correlated with the type of pathogen (r=-0.785, -0.793 and -0.822 respectively; P<0.001). ROC curve showed that serum levels of PCT, endotoxin and CRP were valuable for prognosis prediction in sepsis patients (AUC=0.862, 0.831 and 0.827 respectively; P<0.001), and combination of the three levels was more valuable for the prognosis prediction (AUC=0.911, P<0.001).  Conclusion  The serum levels of PCT, endotoxin and CRP were higher in sepsis patients due to Gram-negative bacterial infection than those due to Gram-negative bacterial infection. Combination of the three serum biomarkers can be used as an adjuvant to predict prognosis in sepsis patients.

Key words: Sepsis, Procalcitonin, Endotoxin, C-reactive protein, Pathogenic bacteria, Prognosis