Ability of procalcitonin to diagnose bacterial infection and bacteria types compared with blood culture findings

Abstract

Procalcitonin (PCT) and C-reactive protein serve as biomarkers of infection in patients with sepsis/bacteremia. The present study assessed the clinical characteristics of 280 patients with suspected sepsis who were admitted to Tohoku Medical and Pharmaceutical University Hospital between January 2012 and December 2013. Among the patients, 133 and 147 were positive and negative for PCT, respectively. Patients who were PCT positive were older and more frequently male, had reduced levels of platelets and albumin, and increased levels of aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine, and C-reactive protein. Patients who were PCT positive had significantly higher blood culture positivity compared with those who were PCT negative, and the sensitivity and specificity of PCT for detecting positive blood cultures were 74.5% and 59.1%, respectively. Escherichia coli was detected in PCT-positive patients, whereas Staphylococcus epidermidis and Staphylococcus lugdunensis were frequently detected in PCT-negative patients. Levels of PCT were higher in the patients infected with gram-negative rods than those with gram-positive cocci. Furthermore, extended-spectrum β-lactamase (ESBL)-producing bacteria cases showed higher levels of PCT than those of non-ESBL cases. These results suggest that PCT may be a useful biomarker of sepsis, and it might serve as a strong tool to detect patients with severe gram-negative rod bacteremia including ESBL-producing bacteria cases early due to its relative high sensitivity.

Keywords: ESBL; Escherichia coli; biomarker; gram-negative rods; sepsis.

Figure 1

Comparisons of PCT concentrations in the bacteremia patients according to isolated bacterial species. Note: Significant at **P<0.01 and *P<0.05. Abbreviations: PCT, procalcitonin; E. coli, Escherichia coli; K. pneu, Klebsiella pneumoniae; S. aureus, Staphylococcus aureus; S. epi, Staphylococcus epidermidis.

Figure 2

Comparisons of PCT concentrations in the bacteremia patients. Notes: Comparisons of PCT concentrations between patients infected with gram-negative rods and gram-positive cocci (A) and between those infected with ESBL-producing and non-ESBL-producing E. coli and P. mirabilis (B). Significant at **P<0.01 and *P<0.05. Abbreviations: PCT, procalcitonin; ESBL, extended-spectrum β-lactamase; E. coli, Escherichia coli; P. mirabilis, Proteus mirabilis.