Role of procalcitonin in predicting etiology in bacteremic patients: Report from a large single-center experience.
BACKGROUND
Procalcitonin (PCT) is routinely used for an early recognition of severe infections and for promoting appropriate use of antibiotics. However, limited data correlating values of PCT with etiology of infection has been reported.


METHODS
During 2016, all positive blood cultures (BC) were retrospectively extracted in a 1100-beds Italian tertiary-care hospital. PCT and C-reactive protein (CRP) values were recorded within 24h from BC collection. Primary endpoint of the study was to investigate the correlation between PCT and CRP values and the occurrence of bloodstream infections (BSI) caused by bacteria or fungi.


RESULTS
During the study period, 1296 positive BC were included: 712 (54.9%) due to Gram-positive (GP), 525 (40.5%) due to Gram-negative (GN) strains, and 59 (4.6%) caused by fungi. Among GN isolates, enterobacteriaceae were reported in 453 (86.3%) cases. PCT values were higher in patients with GN etiology (26.1±14.2ng/mL) compared to GP (6.9±4.5) and fungi (3.3±2.4). Mean values for CRP in GN, GP, and fungi were not different. Receiver Operating Characteristic (ROC) curves showed an area under curve (AUC) of 0.71 for PCT and 0.51 for CRP among GN isolates; an AUC of 0.7 for PCT and 0.52 for CRP among enterobacteriaceae. Lower AUC for PCT were reported for GP and fungi.


CONCLUSIONS
PCT showed moderate performance in early detection (within 24h) of Gram-negative infections, especially those caused by enterobacteriaceae. Further prospective studies are mandatory to confirm these observations.
['Bassetti|Matteo|M|', 'Russo|Alessandro|A|', 'Righi|Elda|E|', 'Dolso|Elisabetta|E|', 'Merelli|Maria|M|', "D'Aurizio|Federica|F|", 'Sartor|Assunta|A|', 'Curcio|Francesco|F|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D019540:Area Under Curve D016470:Bacteremia D015415:Biomarkers D005260:Female D016905:Gram-Negative Bacterial Infections D016908:Gram-Positive Bacterial Infections D006760:Hospitalization D006801:Humans D007362:Intensive Care Units D007558:Italy D008297:Male D008875:Middle Aged D000077740:Procalcitonin D011446:Prospective Studies D012372:ROC Curve D012189:Retrospective Studies
Procalcitonin C-reactive protein Gram-negative Enterobacteriaceae Bacteremia