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Strain-resource engineering is often considered as an important infrastructure of microbiology related research and industry. The western developed countries took the lead in establishing the classical microbial resource utilization method, and continuously improved the preservation system, species annotation technology and global sharing mechanism, which realized the expansion and reserve of biological resources since end of the 19th century. The rich and diversified germplasm resources, standard strains and production strains not only have important economic values, but also maintain the advantages of scientific research, bioeconomy (such as antimicrobial agents, vaccines, detection reagent development and standard development, etc.) and national security. Although there has been a lot of progress in related research in recent years, compared with developed countries, there is still a big gap in related fields in China. The investment and top-level design in this area lag far behind the western developed countries, and it is not commensurate with the current level of economic and social development in my country. Drawing lessons from the practice of WFCC and WDCM (World Data Center for Microorganisms, Global microbial data Center, affiliated to WFCC), for the purpose of collecting new clinical species/strains, this paper puts forward some suggestions on the identification, preservation and upload system of isolates.
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Objective:To explore and evaluate a appropriate suitable method for detection of Campylobacter and antibiotic sensitivity test for foodborne diarrhea in clinical laboratories. Methods:Pre-experiment:a total number of 400 fecal samples of patients with foodborne diarrhea were prospectively collected from the intestinal disease clinic of Beijing Tongren Hospital from September 2017 to January 2018. Double-hole filtration culture method and modified cefoperazone charcoal deoxycholate (CCD) agar culture method were used for fecal culture in micro-aerobic environment for 48 hours, and then suspicious colonies were identified by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Meanwhile, C. jejuni and C. coli were detected by real-time quantitative polymerase chain reaction(qPCR). Large sample verification: 2 062 fecal samples of patients with foodborne diarrhea in three hospitals of different levels in different areas of Beijing were collected for qPCR detection and culture from April 2018 to March 2019. The antimicrobial sensitivity test (AST) of C. jejuni and C. coli was performed according to the disk diffusion method and agar dilution method recommended by Clinical and Laboratory Standards Institute and National Antimicrobial Resistance Monitoring System for Enteric Bacteria. The results of the three detection methods and the consistency of the two antibiotic sensitivity tests were compared. Results:In the pre-experiment, the positive rates of Campylobacter ( jejuni/coli) detected of qPCR, double-hole filtration culture and modified CCD agar culture were 9.0% (36/400), 5.0% (20/400)and 3.5% (14/400), and the difference was statistically significant ( P<0.01). The samples with negative result of qPCR were negative by both culture methods. The total positive rates of Campylobacter detected by qPCR was 8.1% (168/ 2 062)including 7.0% (144/2 062) for C. jejuni and 1.2% (24/2 062) for C. coli. The samples with positive qPCR results were cultured by double-hole filtration culture method and the positive rate was 61.9%(104/168), among which, the positive rate of C. jejuni and C. coli were 58.3%(84/144) and 83.3%(20/24) respectively, which was not significantly different from the detection rate and culture positive rate in the pre-test ( P>0.1). The resistance rates of C. jejuni and C. coli to ciprofloxacin were 94.0%(94/100) and 100.0%(24/24) and to erythromycin were 6.0%(6/100) and 33.3%(8/24). The results from two antibiotic sensitivity test methods were consistent (Kappa>0.75). Conclusions:qPCR is rapid, sensitive and easy to operate, so it is suitable for routine development in clinical laboratories. The double-hole filtration culture method is beneficial to the acquisition of strains and is essential for the further study of Campylobacter. There was no significant difference between agar dilution method and disk diffusion method in antibiotic sensitivity test. Campylobacter showed a very high resistance rate to quinolones, which was no longer suitable for the treatment of Campylobacter foodborne diarrhea in Beijing area. Macrocyclic lipid antibiotics should be preferred.
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Objective:To quantitatively analyze the clinical and drug resistance feature of diarrhea of adults patients in 2016 and 2019 induced by the Escherichia coli (diarrheagenic Escherichia coli, DEC), and to reveal the difference of DEC′s epidemiological features of before and after measuring to strengthen food hygiene and safety in Beijing. Methods:A total number of 3 408 patients with food-borne adult diarrhea were received diagnosis and treatment in the intestinal clinic department of Beijing Tongren Hospital in 2016 and 2019.There were 1 926 patients in 2016 and 1 482 in 2019, respectively. The clinical information of patient were entered into the intestinal early warning system and were carefully preserved. The clinical specimens (the stool samples) were isolated and the DECs were identified by culturing. The colony of DECs was identified by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Five pathogenic types of Escherichia coli were classified by multiplex PCR methods. The drug-susceptibility test was performed according to the standards of the American Society for Clinical and Laboratory Standardization in 2019. The categorical data were analyzed by χ 2 test or Fisher′s exact test to verify the statistical difference. Results:A total number of 581 DECs strains were detected in 3 408 specimens. Among the subtypes of E Coli, the Enterotoxigenic Escherichia coli (ETEC) accounted for 53.36% (310/581), and Enterohemorrhagic Escherichia coli (EHEC) was detected. In 2016, the total detection rate of DEC was 14.54% (280/1 926), enteroaggregative Escherichia coli (EAEC) accounted for 18.21% (51/280), and ETEC accounted for 71.79% (173/280). In 2019, the total detection rate of DEC was 20.31% (301/1 482), EAEC accounted for 41.23% (116/301), and ETEC accounted for 48.93% (137/301). Compared with 2016, the detection rate of EAEC in 2019 increased significantly (χ2=29.26, P<0.001), followed by EPEC (χ2=9.37, P=0.002), and ETEC decreased (χ2=15.43, P<0.001). Compared with other pathogenic types, EAEC can easily cause nausea(χ2=32.72, P<0.001).The red blood cells(χ2=16.44, P=0.001) or the white blood cells (χ2=26.82, P<0.001) could be easily observed in stool specimens of patients infected with enteroinvasive Escherichia coli (EIEC). The resistance rates of EIEC to ampicillin, ampicillin/sulbactam and gentamicin were 80.95% (17/21), 66.67% (14/21) and 57.14% (12/21), respectively. Three strains of EAEC resistant to carbapenem antimicrobials were discovered in 2019 and of which two strains were resistant to ertapenem and imipenem, and the other one strain was only resistant to ertapenem. The whole genomic sequencing showed that there are multiple resistance mechanisms: including the mainly drug-resistant nodular cell differentiation family efflux pump, penicillin binding site mutation, and New Delhi metal-β-lactamase 5 production. Conclusions:The detection rate of DECs in adult patients with food-borne diarrhea is high, and the foremost subtype of DECs is ETEC. Compared with 2016, the detection rates of ETEC in clinical specimens decreased in 2019, and the detection rate of EAEC increased significantly, respectively. In 2019, a carbapenem-resistant antibacterial drug-resistant Escherichia coli strain was isolated. It is of great significance to focus on the biological characteristics and epidemiological changes of DEC.
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Objective To analyze the stress distributions under static loading and impact simulation in the process of tibial plateau fracture using finite element analysis,providing evidence for individualized diagnosis and treatment of tibial plateau fracture.Methods A healthy male volunteer was recruited.A 3D finite element model of a whole knee joint with ligaments,menisci and articular surfaces was generated using CT,MRI and 3D finite element software.The knee joint model was given the nature and parameters after reconstruction.According to the features of tibial plateau fracture,different operating conditions were designed.The stress distributions under static loading and impact simulation in the process of tibial plateau fracture were characterized by finite element analysis.Results Under static loads on the lateral condyle of the tibia,the stress was mainly concentrated on the front edge of the tibial plateau,especially the lateral stress.The stress on the medial condyle of the tibia was significantly increased,and the medial stress extended downwards to the tibial shaft.When the vertical stress moved towards outside,it extended from both sides of the internal and external condyles downwards to the tibia,and the value of lateral platform stress was slightly larger than that on the inside.In collisions,the stresses distributed on the neutral position were the same with the static loads.The stress on the medial condyle of the tibia was significantly increased,extending downwards the tibial shaft when it fell to the inside slope.When it fell to the outside slope,the stress on the tibial plateau was mainly distributed on most of the front edges of lateral and medial platforms,and the stress distributed on the fibula increased obviously.Conclusions The medial tibial plateau plays a major role in bearing stress loads.The stress is more concentrated on the lateral platform but distributed on a larger area of the medial platform,extending downwards the metaphysis.Therefore,small split fractures are likely to occur on the outer edge of the platform while fractures of a large fragment are likely to occur on the medial platform,even involving the metaphysis.
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Objective To study the metabolic profiles in the urine samples of rats dosed with decoction of the caulis of Aristolochia manshuriensis and the relationship between the results of blood biochemical analysis and histopathological analysis,and to explore the feasibility of the application of NMR-based metabonomics to toxicology of Chinese medicine.Methods Male Wistar rats were administrated by ig 36,32,28,and 24 g/kg of A.manshuriensis or the equal volume of distilled water for 6 d,respectively.Urine were collected and their()~1H-NMR spectra were acquired,and then subjected to data process and principal component ana-(lysis)(PCA).Blood biochemical analysis and histopathological examination were carried out.Results(Compared) to control groups,the urinary concentrations of TMAO,taurine,creatinine,DMG,citrate,and DMA in dosed groups decreased,while those of acetate,alanine,and some other amino acids increased to a great extent.The dosed groups can be readily discriminated from the controls based on PCA,with acetate and TMAO as main discriminators.A good agreement was achieved within clinical chemistry,microscopically examination and PCA data.Conclusion The caulis of A.manshuriensis can induce renal lesion as revealed by the metabonomic analysis of rat urine samples as well as blood biochemical analysis and histopathological examinations.The results show that the metabonomic approach is a promising new technology in toxicology.