Lipid mediators of inflammation as novel plasma biomarkers to identify patients with bacteremia.
OBJECTIVE
Rapid diagnostic tests for bacteremia are important for early treatment to improve clinical outcome. We sought to identify plasma biomarkers that can identify patients with bacteremia using an untargeted global metabolomic analysis.


METHODS
Plasma metabolomic profiles were analyzed for 145 adult patients with (cases) and without (controls) bacteremia using ultra-high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). All metabolites were compared between cases and controls using a 2-tier filtering approach, and each metabolite underwent receiver operating characteristic (ROC) curve analysis. Individual metabolites that distinguish between cases and controls were characterized. Subgroup analysis was performed to identify metabolites with prognostic significance.


RESULTS
After 2-tier filtering, 128 molecular features were identified to be potential biomarkers that could distinguish cases from controls. Five metabolites had an area under the ROC curve (AUC) of >0.8 in ROC curve analysis, including a sphingolipid, an acylcarnitine, a fatty acid ester, and 2 glycerophosphocholines. These metabolites could distinguish cases from controls in the unsupervised hierarchical clustering analysis. Subgroup analysis of bacteremic patients showed that the level of trans-2,3,4-trimethoxycinnamate was lower in fatal than non-fatal cases.


CONCLUSIONS
Plasma lipid mediators of inflammation can distinguish bacteremia cases from non-bacteremia controls. These biomarkers may be used as targets for rapid test in clinical practice.
State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China; Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China; Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China; Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Kelvin K W
KK
To
Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Kim-Chung
KC
Lee
State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China; Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China; Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China; Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Samson S Y
SS
Wong
Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Ka-Ching
KC
Lo
Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Yin-Ming
YM
Lui
Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Akhee S
AS
Jahan
Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Andrea L
AL
Wu
Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Yi-Hong
YH
Ke
Department of Pathology, The University of Hong Kong, Hong Kong, China.
Chun-Yiu
CY
Law
Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Kong-Hung
KH
Sze
State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China; Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China; Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China; Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Susanna K P
SK
Lau
State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China; Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China; Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China; Department of Microbiology, The University of Hong Kong, Hong Kong, China.
Patrick C Y
PC
Woo
Department of Pathology, The University of Hong Kong, Hong Kong, China.
Ching-Wan
CW
Lam
State Key Laboratory for Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China; Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China; Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China; Department of Microbiology, The University of Hong Kong, Hong Kong, China. Electronic address: kyyuen@hku.hk.
Kwok-Yung
KY
Yuen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000097:blood / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D005227:Fatty Acids / Q000097:blood; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000302:isolation & purification*; D008055:Lipids / Q000097:blood*; D008297:Male; D055432:Metabolomics; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D013107:Sphingolipids / Q000097:blood
D015415:Biomarkers; D005227:Fatty Acids; D018836:Inflammation Mediators; D008055:Lipids; D013107:Sphingolipids; C116917:acylcarnitine; D002331:Carnitine
Bacteremia; Biomarker; Lipid; Metabolomic; Organic acid; Plasma