Objective The aim of this study was to evaluate procalcitonin (PCT) diagnostic accuracy in discriminating gram-negative (GN) from gram-positive (GP) bloodstream infections and determining the relationship between PCT levels, infection sites, and pathogen types. Methods Clinical and laboratory data were collected from patients with blood culture (BC)-positive sepsis between January 2014 and December 2015. PCT levels at different infection sites were compared, as was the presence of GN and GP bloodstream infection. A receiver operating characteristic (ROC) curve was generated to assess diagnostic accuracy. Results Of the 486 monomicrobial BCs, 254 (52.26%) were positive for GN bacteria (GNB), and 202 (42.18%) for GP bacteria (GPB). Median PCT levels were higher in BCs positive for GN (2.42 ng/ml, IQR: 0.38–15.52) than in those positive for GPB (0.49 ng/ml, IQR: 0.13–5.89) (P < 0.001). In the ROC analysis to differentiate between GNB and GPB, the area under the curve was 0.628 (95% CI: 0.576–0.679). When the cutoffs for PCT were 10.335 and 15.000 ng/ml, the specificity of GNB infection was 80.2% and 84.2%, respectively. PCT levels caused by GNB differed between Escherichia coli and Acinetobacter baumanni/Burkholderia cepacia, Klebsiella pneumonia and Acinetobacter baumanni. PCT levels caused by GPB differed between Staphylococcus epidermidis/Staphylococcus aureus and Staphylococcus hominis/Staphylococcus haemolyticus, Enterococcus faecium and Enterococcus faecalis/S.hominis/S. haemolyticus. Among patients with known infection sites, there were statistical differences in PCT levels between abdominal infection and pneumonia/infective endocarditis, urinary tract infection and pneumonia/catheter-related infection/infective endocarditis. Conclusion PCT can distinguish between GNB and GPB infection, as well as between different bacterial species and infection sites.
Yan, S. T., Sun, L. C., Jia, H. B., Gao, W., Yang, J. P., & Zhang, G. Q. (2017). Procalcitonin levels in bloodstream infections caused by different sources and species of bacteria. American Journal of Emergency Medicine, 35(4), 579–583. https://doi.org/10.1016/j.ajem.2016.12.017