ABSTRACT
Objective To evaluate the potential value of next-generation sequencing ( NGS) as a diagnostic method for listeria infection in central nervous system ( CNS ) . Methods To identify the potentially pathogenic microorganisms ( PPMs) of the five patients with CNS infection in the Department of Neurology, People's Hospital of Zhengzhou University from June 2017 to November 2017, blood or cerebrospinal fluid ( CSF ) was detected not only using common laboratory tests , including routine , biochemical, cytologic, culture and Gram-staining methods, etc, but also using the BGISEQ-100 sequencing platform to identify the PPMs of CSF .Concomitantly , we collected concurrent clinical data , then performed a comprehensive analysis of their clinical , laboratory , and auxiliary examination data .Results Of the five cases (male :female: 1:4, age ranges: 26 -61 years), the disease mainly occurred in summer.Three patients received immunosuppressants treatment before infection , and three patients had gastrointestinal syndrome in the prodromal period .Infection of CNS led to fever , headache and meningeal irritation sign in all the patients.The medical imaging examinations showed the invasion of meninges , brainstem, and the periventricular gray matter.The cell count of CSF was more than 500 ×106/L.NGS techniques showed listeria genome sequence ranged from 57 to 2611, and the coverage of listeria varied from 0.23％ to 14.00％, and PCR results supported the existence of listeria .Conclusion NGS is beneficial to make the diagnosis of listeria infection in CNS , and can help guide early treatment .
ABSTRACT
Objective To apply hydride generation atomic fluorescence spectrophotometry (HG-AFS method) in urinary arsenic detection,and to provide a better,newer and more convenient detection method for quantitative analysis of urinary arsenic.Methods According to the Guide to Develop Biological Sample Inspection Method(WS/T 68-1996) and Guide for Establishing Occupational Health Standards-part 5:Determination Methods in Biological Materials (GB/T 210.5-2008),HG-AFS method was established to detect arsenic content in urine after modification of the method for sample pretreatment,and to verify the linear range of standard curve and linearity,detection limit,precision,accuracy,stability of the sample,and to compare the experimental results of HG-AFS method with those of standard methods of WS/T 28-1996 and Determination of Arsenic in Urine by Cyanide Generation Atomic Fluorescence Method (WS/T 474-2015).Results The HG-AFS method linear range was from 0-100 μg/L,the correlation coefficient r =0.999 9,the detection limit was 0.07 μg/L,the precision was 1.96％-3.97％,and the recovery rate was 95.1％-105.0％.There was no statistical significance between HG-AFS method,the standard of WS/T 28-1996 or WS/T 474-2015 methods (t =1.539,0.353,all P ＞ 0.05).Conclusion The new method is superior to the current detection method owing to its low detection limit,high precision,good accuracy,and wide linear range.
ABSTRACT
BACKGROUND AND PURPOSE: Encephalitis caused by Listeria monocytogenes (L. monocytogenes) is rare but sometimes fatal. Early diagnosis is difficult using routine cerebrospinal fluid (CSF) tests, while next-generation sequencing (NGS) is increasingly being used for the detection and characterization of pathogens. METHODS: This study set up and applied unbiased NGS to detect L. monocytogenes in CSF collected from three cases of clinically suspected listeria meningoencephalitis. RESULTS: Three cases of patients with acute/subacute meningoencephalitis are reported. Magnetic resonance imaging and blood cultures led to a suspected diagnosis of L. monocytogenes, while the CSF cultures were negative. Unbiased NGS of CSF identified and sequenced reads corresponding to L. monocytogenes in all three cases. CONCLUSIONS: This is the first report highlighting the feasibility of applying NGS of CSF as a diagnostic method for central nervous system (CNS) L. monocytogenes infection. Routine application of this technology in clinical microbiology will significantly improve diagnostic methods for CNS infectious diseases.