Development and validation of an advanced fragment analysis-based assay for the detection of 22 pathogens in the cerebrospinal fluid of patients with meningitis and encephalitis.

BACKGROUND: Meningitis and encephalitis (ME) are central nervous system (CNS) infections mainly caused by bacteria, mycobacteria, fungi, viruses, and parasites that result in high morbidity and mortality. The early, accurate diagnosis of pathogens in the cerebrospinal fluid (CSF) and timely medication are associated with better prognosis. Conventional methods, such as culture, microscopic examination, serological detection, CSF routine analysis, and radiological findings, either are time-consuming or lack sensitivity and specificity. METHODS: To address these clinical needs, we developed an advanced fragment analysis (AFA)-based assay for the multiplex detection of 22 common ME pathogens, including eight viruses, 11 bacteria, and three fungi. The detection sensitivity of each target was evaluated with a recombinant plasmid. The limits of detection of the 22 pathogens ranged from 15 to 120 copies/reaction. We performed a retrospective study to analyze the pathogens from the CSF specimens of 170 clinically diagnosed ME patients using an AFA-based assay and compared the results with culture (bacteria and fungi), microscopic examination (fungi), polymerase chain reaction (PCR) (Mycobacterium tuberculosis), and Sanger sequencing (virus) results. RESULTS: The sensitivity of the AFA assay was 100% for 10 analytes. For Cryptococcus neoformans, the sensitivity was 63.6%. The overall specificity was 98.2%. The turnaround time was reduced to 4-6 hours from the 3-7 days required using conventional methods. CONCLUSIONS: In conclusion, the AFA-based assay provides a rapid, sensitive, and accurate method for pathogen detection from CSF samples.

Direct interaction between selenoprotein R and Aß42.

Amyloid-ß (Aß) peptides have taken a central role in AD research, the aggregation of Aß peptide is involved in the progression of Alzheimer's disease (AD). The 35th amino acid was methionine (Met) in Aß peptides and it's redox state is critical in determining the biological activity of Aß. It has been suggested that oxidation of Met35 (Met35O) plays a key role in the formation of paranuclei and in the control of oligomerization pathway choice. As an antioxidative selenoenzyme, Selenoprotein R (SelR) plays important roles in reducing the R-form of MetO to Met to maintain intracellular redox balance. However, the relationship between SelR and Aß was little investigated. Here, we found that SelR can directly interact with Aß42, and the interaction between SelR and Aß42 was verified by fluorescence resonance energy transfer (FRET), co-immunoprecipitation (co-IP), and pull-down assays. SelR is closely related to AD, its biological functions in human brain become a research focus. This work implies that SelR makes it capable of modulating Aß42 aggregation and provides a novel avenue for further study on the mechanism of SelR in AD prevention.