Pathogen identification in culture-negative cerebrospinal fluid specimens of patients with purulent meningitis using next-generation sequencing technology.

Antimicrobial therapy necessitates fast and accurate detection of pathogens in purulent meningitis (PM) diagnosis. Although considered a gold standard, the traditional bacterial detection and identification methods based on routine bacterial culture are time-consuming and show low sensitivity and specificity. In order to reduce PM-related deaths and improve the treatment efficiency, we employed trace DNA extraction technology and combined it with Next-Generation Sequencing technology for bacteria identification. We extracted DNA from 31 cerebrospinal fluid (CSF) samples from people with PM. The samples were collected by lumbar puncture at Xi'an Children Hospital under a stringent protocol. Ion PGMTM System Next-Generation Sequencing was used to screen for pathogens in the CSF samples based on their 16S ribosomal RNA (rRNA) genes. Of the 31 CSF samples, 29 were culture negative. Streptococcus was detected in 2 samples by culture-based methods. The species identified by Next-Generation Sequencing showed a diverse bacterial population that included Streptococcus (22.6%), Escherichia (15.9%), Peptostreptococcus (10.7%), Pseudomonas (10.5%), Rothia (8.8%), Acinetobacter (4.9%), Prevotella (4.1%), Bacillus (3.3%), Neisseria (2.5%), Catonella (2.4%), Acitinomyces (2.0%), and Citrobacter (2.0%). Clustering analysis revealed three major bacterial groups, namely Streptococcus, Escherichia and Acinetobacter, each group with a different proportion of bacterial species. The results indicated that PM may result from infections by multiple bacterial species as opposed to a single species, with infectivity determined by abundance of the dominant species. Furthermore, Next-Generation Sequencing allowed a sensitive and specific etiological basis for identification of pathogens not only in the cerebrospinal fluid specimens, but also in other clinical samples.

Study of the pharmacokinetics of polymerized porcine hemoglobin (pPolyHb).

Polymerized porcine hemoglobin (pPolyHb), a kind of glutaraldehyde-polymerized haemoglobin-based oxygen carrier, was developed as a potential red blood substitute for clinical applications. Assessment of its absorption, distribution, and metabolism is a major determinant of its safety and efficacy. In this study, a series of pharmacokinetic parameters of pPolyHb were measured and calculated in different animal models, such as the top-load model, the 50% exchange transfusion model and the haemorrhagic shock model. The results showed that the kinetic process of pPolyHb in rats conforms to the laws of linear pharmacokinetics in vivo. The half-life of pPolyHb was superior and more stable under non-pathological conditions, but in clinical situations such as trauma and anaemia, the half-life of pPolyHb may decline. The study of clearance (CL) and the apparent volume of distribution (Vd) of pPolyHb in these three different animal models demonstrated longer residence and a predominant, targeted role of pPolyHb with little accumulation in tissues. Through this study, the superior pharmacokinetic characteristics of pPolyHb have been proved and will aid in the determination of a reasonable dosing regimen and administration interval in clinical situations.

Genetic polymorphisms of pharmacogenomic VIP variants in the Yi population from China.

INTRODUCTION: Drug response and target therapeutic dosage are different among individuals. The variability is largely genetically determined. With the development of pharmacogenetics and pharmacogenomics, widespread research have provided us a wealth of information on drug-related genetic polymorphisms, and the very important pharmacogenetic (VIP) variants have been identified for the major populations around the world whereas less is known regarding minorities in China, including the Yi ethnic group. Our research aims to screen the potential genetic variants in Yi population on pharmacogenomics and provide a theoretical basis for future medication guidance. MATERIALS AND METHODS: In the present study, 80 VIP variants (selected from the PharmGKB database) were genotyped in 100 unrelated and healthy Yi adults recruited for our research. Through statistical analysis, we made a comparison between the Yi and other 11 populations listed in the HapMap database for significant SNPs detection. Two specific SNPs were subsequently enrolled in an observation on global allele distribution with the frequencies downloaded from ALlele FREquency Database. Moreover, F-statistics (Fst), genetic structure and phylogenetic tree analyses were conducted for determination of genetic similarity between the 12 ethnic groups. RESULTS: Using the χ2 tests, rs1128503 (ABCB1), rs7294 (VKORC1), rs9934438 (VKORC1), rs1540339 (VDR) and rs689466 (PTGS2) were identified as the significantly different loci for further analysis. The global allele distribution revealed that the allele "A" of rs1540339 and rs9934438 were more frequent in Yi people, which was consistent with the most populations in East Asia. F-statistics (Fst), genetic structure and phylogenetic tree analyses demonstrated that the Yi and CHD shared a closest relationship on their genetic backgrounds. Additionally, Yi was considered similar to the Han people from Shaanxi province among the domestic ethnic populations in China. CONCLUSIONS: Our results demonstrated significant differences on several polymorphic SNPs and supplement the pharmacogenomic information for the Yi population, which could provide new strategies for optimizing clinical medication in accordance with the genetic determinants of drug toxicity and efficacy.