Serum N-Glycomics Stratifies Bacteremic Patients Infected with Different Pathogens

Abstract

Bacteremia—i.e., the presence of pathogens in the blood stream—is associated with long-term morbidity and is a potential precursor condition to life-threatening sepsis. Timely detection of bacteremia is therefore critical to reduce patient mortality, but existing methods lack precision, speed, and sensitivity to effectively stratify bacteremic patients. Herein, we tested the potential of quantitative serum N-glycomics performed using porous graphitized carbon liquid chromatography tandem mass spectrometry to stratify bacteremic patients infected with Escherichia coli (n = 11), Staphylococcus aureus (n = 11), Pseudomonas aeruginosa (n = 5), and Streptococcus viridans (n = 5) from healthy donors (n = 39). In total, 62 N-glycan isomers spanning 41 glycan compositions primarily comprising complex-type core fucosylated, bisecting N-acetylglucosamine (GlcNAc), and α2,3-/α2,6-sialylated structures were profiled across all samples using label-free quantitation. Excitingly, unsupervised hierarchical clustering and principal component analysis of the serum N-glycome data accurately separated the patient groups. P. aeruginosa-infected patients displayed prominent N-glycome aberrations involving elevated levels of fucosylation and bisecting GlcNAcylation and reduced sialylation relative to other bacteremic patients. Notably, receiver operating characteristic analyses demonstrated that a single N-glycan isomer could effectively stratify each of the four bacteremic patient groups from the healthy donors (area under the curve 0.93–1.00). Thus, the serum N-glycome represents a new hitherto unexplored class of potential diagnostic markers for bloodstream infections.

Total serum N-glycans mark visceral leishmaniasis in human infections with Leishmania infantum

“… 51 The serum N -glycome from patients infected with Pseudomonas aeruginosa , an opportunistic gram-negative pathogen closely associated with cystic fibrosis affecting lung and liver, shows increased levels of core fucosylation (as well as decreased levels of sialylation, which will be discussed later). 52 Core fucosylation levels are also increased in advanced stages of pancreatic cancer, however the authors of that study suggested that the biological function seemed to be related to the disease itself and not to the inflammation. 53 Similar glycan profiles have been described for (auto)inflammatory diseases such as rheumatoid arthritis 54 and Crohn’s disease, 30 , 55 in which fucosylation of a tri-antennary structure, indicated as an inflammatory marker, was elevated.…”

“… 62 On the other hand, bisection was significantly higher in meningitis patients presenting with the most severe clinical outcomes. 63 Bisection also discriminates between pathogens that cause bacteremia, 52 possibly reflecting differences in their microbial-associated molecular patterns and respective strengths in activating innate immune signaling pathways.…”

Impact of infection on proteome-wide glycosylation revealed by distinct signatures for bacterial and viral pathogens

“…Various types of host biomarkers have been targeted to distinguish viral from bacterial infections: RNA markers, 26 , 27 , 28 , 29 host protein markers, 30 , 31 , 32 host plasma lipids, 33 and the (released) host N-glycome. 34 To the best of our knowledge, we are the first to find pathogen-specific host markers by analysis of intact glycopeptides in full plasma. We observed site-specific differences in N-glycosylation, of which several are highly significant signatures to distinguish bacterial from viral infection.…”

Acute Lyme disease IgG N-linked glycans contrast the canonical inflammatory signature

“…Interestingly, murine studies have demonstrated a reduction in the general humoral response after LD infection as indicated by low titers of anti-viral antibodies produced post-vaccination and Bbimpaired helper T-cell mediated affinity maturation (87,95). Lastly, because the LD cohort completed 2-3 week of oral doxycycline therapy, the serum N-glycome or immune response could have been altered in part due to changes in gut flora (96,97).…”