A Proteomic Approach for the Diagnosis of Bacterial Meningitis

Abstract

BackgroundThe discrimination of bacterial meningitis (BM) versus viral meningitis (VM) shapes up as a problem, when laboratory data are not equivocal, in particular, when Gram stain is negative.Methodology/Principal FindingsWith the aim to determine reliable marker for bacterial or viral meningitis, we subjected cerebrospinal fluid (CSF) to a quantitative proteomic screening. By using a recently established 2D-DIGE protocol which was adapted to the individual CSF flow, we compared a small set of patients with proven BM and VM. Thereby, we identified six potential biomarkers out of which Prostaglandin-H2 D-isomerase was already described in BM, showing proof of concept. In the subsequent validation phase on a more comprehensive collective of 80 patients, we could validate that in BM high levels of glial fibrillary acidic protein (GFAP) and low levels of soluble amyloid precursor protein alpha/beta (sAPPα/β) are present as possible binding partner of Fibulin-1.Conclusions/SignificanceWe conclude that our CSF flow-adapted 2D-DIGE protocol is valid especially in comparing samples with high differences in total protein and suppose that GFAP and sAPPα/β have a high potential as additional diagnostic markers for differentiation of BM from VM. In the clinical setting, this might lead to an improved early diagnosis and to an individual therapy.

Quantitative Proteomics of Cerebrospinal Fluid in Paediatric Pneumococcal Meningitis

“…The complement system is involved in phagocytosis and the assembly of the membrane attack complex, which promotes cell lysis by forming pores in the membrane of gram-negative bacteria 39 . From our data and those from previous studies on pneumococcal meningitis, complement C3 is increased in SPP samples 8 , 9 , 40 and here, we demonstrate an increase in concentration of other components of the complement system from the classical pathway (complement C4-A (UniprotKB P0C0L4), Complement C1r subcomponent (UniprotKB P00736), complement factor I (UniprotKB P05156), Complement C2 (UniprotKB P06681)) and the alternative pathway (complement factor B (UniprotKB P00751) and complement factor H (UniprotKB P08603)). Further, the membrane attack complex (complement C6 (UniprotKB P13671), C7 (UniprotKB P10643) and C9 (UniprotKB P02748)) is also more abundant in SPP samples.…”

Two dimensional difference gel electrophoresis analysis of cerebrospinal fluid in tuberculous meningitis patients

“…Generally, equal amount of protein labeled with Cy dyes is compared in DIGE analysis [18,19]. However, equal volume of CSF labeled with Cy dyes is also used to compare the protein expression levels per volume of CSF [11,13]. We analyzed our samples according to both the protocols.…”

“…3). GFAP levels have been known to be raised in other neurological conditions such as bacterial meningitis [11], systemic lupus erythematosus [36], HIV associated dementia [37], trypanosomiasis [38] signifying considerable brain tissue damage in these diseases. GFAP is a biomarker of astrocytes injury as shown in murine models [39].…”

“…People with ApoE2 and E4 genotypes are more susceptible to pulmonary tuberculosis than E3 genotype [49]. ApoE levels are also decreased in bacterial meningitis [11] and post subarachnoid hemorrhage [50]. Apolipoprotein E and A-I are being extensively studied in post head injury patients [51], multiple sclerosis [52] and cardiovascular diseases [53,54] for their anti-inflammatory properties.…”

“…CSF proteomics is an ideal choice for investigating potential TBM protein markers because CSF proteins are reflective of the environment in the vicinity of the meninges and brain. CSF 2D-DIGE has been used frequently in identifying potential biomarkers in various neurological diseases like bacterial meningitis [11], multiple sclerosis [12] and Creutzfeldt-Jakob disease [13]. Here, we report, for the first time, the DIGE analysis of CSF from tuberculous meningitis patients and mass spectrometric identification of differentially expressed proteins.…”