Identification of Vibrio parahaemolyticus based on the concatenated DNA sequencing of 16S rRNA and gyrB gene / 上海预防医学

Objective:To establish the concatenated DNA sequencing of 16S ribosomal RNA （16S rRNA） and DNA gyrase subunit B （gyrB） gene， and provide evidence for the identification and classification of Vibrio parahaemolyticus （V. parahaemolyticus）. Methods:Typical strains in the genus of Vibrio spp. was selected， such as V. parahaemolyticus， V. alginolyticus and other species for examination of 16S rRNA and gyrB gene as target. Primers were separately designed to amplify these two nucleotide fragments. Phylogenetic analysis was performed using the concatenated sequences. Results:The concatenated 16S rRNA+gyrB nucleotide sequence of V. parahaemolyticus formed a single cluster in the phylogenetic analysis， which identified the typical strains of Vibro spp. at the species level. Conclusion:In our study， an identification method of V. parahaemolyticus is established based on concatenated 16S rRNA+gyrB nucleotide sequencing. It can identify the strains of V. parahaemolyticus at the species level， which may be applied in phylogenetic analysis and contamination tracing of V. parahaemolyticus in food and drug control.

Evaluation of different samples pretreatment method of MALDI-TOF MS on the identification of common foodborne pathogens / 上海预防医学

Objective To evaluate the effects of different sample pretreatment methods of MALDI-TOF MS on the identification of common foodborne pathogens. Methods A total of 51 common foodborne pathogens were collected, covering Salmonella, Staphylococcus, Listeria, Vibrio, Escherichia, and Shigella.Then the effects of three sample treatment methods including direct smear method, in-situ formic acid extraction method and formic acid acetonitrile extraction method of MALDI-TOF MS on the identification of common foodborne pathogens were evaluated. Results There were no significant differences in the identification results of Salmonella, Shigella, and Escherichia by three sample pretreatment methods; Staphylococcus captis, Staphylococcus cohnii, Vibrio parahaemolyticus and Vibrio vulnificus could not be identified effectively by direct smear method, but these strains could be accurately identified by other methods.Non-listeria monocytogenes strains of listeria genus were often mistakenly identified by using direct smear method and in-situ formic acid extraction method, and the use of formic acid and acetonitrile extraction could improve the identification accuracy for different species of listeria. Conclusion Different sample pretreatment methods of MALDI-TOF MS have certain influence on the identification of common foodborne pathogenic bacteria.Therefore, selecting appropriate sample pretreatment methods is important to obtain reliable and accurate identification results.

Study on the proficiency testing program of pharmaceutical preparation analysis / 药学学报

This proficiency testing program is established to evaluate the pharmaceutical preparation analysis capacity of laboratories recommended by 18 countries and economies. It was authorized by Asia Pacific Laboratory Accreditation Cooperation (APLAC), and organized by Shanghai Institute for Food and Drug Control (SIFDC) and China National Accreditation Service for Conformity Assessment (CNAS). The 0.3sigma test is used to evaluate the homogeneity and stability of the proficiency testing sample. The results of the laboratories were assessed by Z-score. The robust average and the robust standard deviation of the participants' results were calculated as assigned value and standard deviation for performance assessment of hydrochlorothiazide and captopril using robust statistics. Thirty-three of 38 laboratories recommended by 18 countries and economies sent their results back. Twenty-four laboratories' results were observed as satisfactory. Five laboratories were identified as having reported at least one questionable result. Four laboratories were identified as having reported at least one unsatisfactory result.