Genotyping Characteristics of Human Fecal Escherichia coli and Their Association with Multidrug Resistance in Miyun District, Beijing / 生物医学与环境科学（英文）

OBJECTIVE@#To explore the genotyping characteristics of human fecal Escherichia coli( E. coli) and the relationships between antibiotic resistance genes (ARGs) and multidrug resistance (MDR) of E. coli in Miyun District, Beijing, an area with high incidence of infectious diarrheal cases but no related data.@*METHODS@#Over a period of 3 years, 94 E. coli strains were isolated from fecal samples collected from Miyun District Hospital, a surveillance hospital of the National Pathogen Identification Network. The antibiotic susceptibility of the isolates was determined by the broth microdilution method. ARGs, multilocus sequence typing (MLST), and polymorphism trees were analyzed using whole-genome sequencing data (WGS).@*RESULTS@#This study revealed that 68.09% of the isolates had MDR, prevalent and distributed in different clades, with a relatively high rate and low pathogenicity. There was no difference in MDR between the diarrheal (49/70) and healthy groups (15/24).@*CONCLUSION@#We developed a random forest (RF) prediction model of TEM.1 + baeR + mphA + mphB + QnrS1 + AAC.3-IId to identify MDR status, highlighting its potential for early resistance identification. The causes of MDR are likely mobile units transmitting the ARGs. In the future, we will continue to strengthen the monitoring of ARGs and MDR, and increase the number of strains to further verify the accuracy of the MDR markers.

Chemical constituents from stems of Glycosmis pentaphylla / 中草药

Objective: To study the chemical constituents in the stems of Glycosmis pentaphylla. Methods: The constituents were isolated and purified by silica gel and preparative HPLC, and their structures were elucidated by means of physicochemical properties and spectroscopic analyses. Results: Nine compounds were isolated from the n-butanol-soluble fraction of 95% ethanol extract from the stems of G. pentaphylla, and identified as methyl 2-hydroxybenzoate 2-O-β-D-apiofuranosyl-(1→2)-O-β-D-glucopyranoside (1), inosine (2), 4-methoxy-8-(O-β-D-glucopyranosyloxy)-2(1H)-quinolinone (3), threo-guaiacyl-glycerol-8-O-4'-sinapyl ether 7-O-β-D-glucopyranoside (4), vitexin (5), ethyl-O-β-D-glucopyranoside (6), 2-propyl-O-β-D-glucopyranoside (7), threo-guaiacyl glycerol (8), and erythro-guaiacyl glycerol (9). Conclusion: Compound 1 is a new phenolic glycoside named glycopentosine A, and compounds 2-4 and 6-9 are isolated from the plants of Glycosmis Correa for the first time.