Serum procalcitonin levels distinguish Gram-negative bacterial sepsis from Gram-positive bacterial and fungal sepsis.

BACKGROUND

Serum procalcitonin (PCT) levels differ in patients with bacterial or fungal infections and are significantly elevated in patients with Gram-negative bacteremia. We evaluated the diagnostic accuracy of different inflammatory markers to discriminate sepsis caused by different pathogens.

MATERIALS AND METHODS

We included 328 episodes of bacteremia from 292 patients with sepsis and 31 patients with suspected sepsis in this study. Medical records of patients who had bacteremia caused by Gram-negative bacteria (Gram-negative), Gram-positive bacteria (Gram-positive) or fungi were reviewed, and information about PCT and other inflammatory markers was recorded. The diagnostic performance of inflammatory markers was calculated via receiver operating characteristic (ROC) curves.

RESULTS

Serum PCT levels in Gram-negative, Gram-positive, and fungal sepsis were 7.47 (interquartile range [IQR]: 1.09-41.26) ng/mL, 0.48 (IQR: 0.15-2.16) ng/mL, and 0.60 (IQR: 0.14-2.06) ng/mL, respectively ( < 0.001). ROC analysis revealed an optimal cut-off value of 2.44 ng/mL for PCT in discriminating Gram-negative sepsis from Gram-positive sepsis, which yielded a sensitivity of 68.4% and a specificity of 77.1%. An optimal cut-off value of 3.11 ng/mL for PCT in discriminating Gram-negative sepsis from fungal sepsis, led to a sensitivity of 63.9% and specificity of 93.3%. Neither PCT nor other inflammatory markers could be used to distinguish between Gram-positive and fungal sepsis.

CONCLUSION

Serum PCT levels were significantly higher in patients with Gram-negative sepsis than in those with Gram-positive or fungal sepsis. PCT is a potential sensitive biomarker for distinguishing Gram-negative sepsis from Gram-positive and fungal sepsis.