Objective:To analyze the growth characteristics of different genotypes of Japanese encephalitis virus (JEV) in different cell lines, and to provide scientific basis for the selection of cell lines in the study of JEV.Methods:BHK-21, Vero, C6/36, PK-15, DF-1, N2a, SH-sy5y and MDCK cell lines were selected. The proliferation ability of genotype 1 (NX1889 strain), genotype 3 (P3 strain) and genotype 5 (XZ0934 strain) JEV in these cell lines was evaluated by plaque assay and RT-qPCR.Results:Significant cytopathogenic effects (CPE) were observed in BHK-21, Vero, C6/36, DF-1, N2a and PK-15 cell lines across all three JEV genotypes. However, no significant differences in CPE characteristics were observed within the same cell line. SH-sy5y and MDCK cell lines did not show significant CPE, but virus proliferation was detected in SH-sy5y cell line, while MDCK cell line were found to be insensitive to JEV. No significant difference was observed in the proliferation curves of G1, G3 and G5 JEV in BHK-21, Vero and SH-sy5y cell lines. In C6/36 and PK-15 cell lines, the titer of G1 JEV was higher than that of G3 and G5. In DF-1 cell line, G5 demonstrated a higher titer than the other two genotypes, whereas in N2a cell line, G5 showed a lower titer than the other two.Conclusions:There are differences in the proliferation of three different genotypes of JEV in different cell lines, which can provide reference for the study of JEV in different directions.

Background In view of circulatory diseases, most previous studies focused on the impacts of air pollution and meteorological factors, while ignoring the influence of built environment. Objective To investigate and quantify the impact of built environment on circulatory diseases in China. Methods Circulatory disease mortality data and built environment data (including urban greenery coverage, urban land use, urban land use mix, urban road facilities and urban medical facilities) of 17 cities in China from 2000 to 2019 were collected. Multiple linear regression was used to analyze which built environment elements had significant influence on circulatory diseases, and to quantify their effects. Furthermore, the changes of built environment indicators on circulatory disease mortality were evaluated under different levels of urban economic development and various air quality. Results The built environment affected the mortality of circulatory diseases during the study period (P<0.05). Urban green space and commercial land area were negatively correlated with circulatory disease mortality, and regression coefficients were −0.550 and −0.280, respectively (P<0.05). On the contrary, the increase of urban road area, residential land ratio, and the degree of land use mix were positively associated with circulatory disease mortality, and their regression coefficients were 0.322, 0.283, and 0.176, respectively (P<0.05). When the level of urban economic development was low, the impact of commercial land use ratio on circulatory diseases was stronger, and the regression coefficient was −0.476 (P<0.05). When urban air pollution worsened, the impacts of per capita green coverage area and per capita urban road area on the disease were more prominent, and the regression coefficients were −0.528 and 0.372, respectively (P<0.05). Conclusion There is a significant correlation between urban built environment and mortality of circulatory diseases. To be specific, circulatory disease mortality has a negative correlation with per capita green coverage area and commercial land use ratio, and a positive correlation with per capita urban road area, residential land ratio and degree of land use mix.

To optimize the quantitative detection method for Salmonella enterica and analyze the quantitative contamination level of Salmonella enterica in raw pork samples from farmer′s markets in Chengdu. Based on qualitative detection standard method of Salmonella enterica in China (GB 4789.4-2016) and the quantitative detection method of FSIS in the United States (MLG 4.08 and MLG appendix 2.05 MPN), the selective enrichment broth, screening plate, identification method and quantitative dilution ratio in quantitative detection of Salmonella enterica were optimized using 70 samples of raw pork. The optimized method compared by student′s t-test was used to detect 40 samples of raw pork collected from farmer′s markets in Chengdu from June to October 2020. For isolation of Salmonella from raw pork samples, the coincidence degree of TTB enrichment solution was significantly higher than that of RV enrichment solution (0.93±0.32 vs 0.35±0.62, t=8.324, P=0.001) and the consistency of suspicious colonies screened by XLT4 plate was significantly higher than that of Salmonella chromogenic medium (0.77±0.09 vs 1.00±0.00, t=2.971, P =0.017). The MPN method used 4 successive gradient dilutions, namely 12 tube method, could obtain more accurate quantitative value for Salmonella enterica. The combined use of selective enrichment broth TTB, XLT4 plate, Real-time PCR and MALDI-TOF mass spectrometry could get better results for screening and identifying Salmonella enterica. The detection rate for Salmonella enterica isolated from raw pork in farmer′s markets was 92.5% (37/40). The most of the Salmonella positive samples (83.8%, 31/37) were detected with a contamination level ranged from 0.1 to 55 MPN/g. The optimized quantitative detection method for Salmonella enterica in raw pork in this study can effectively screen the target bacteria and obtain more accurate quantitative value.

To optimize the quantitative detection method for Salmonella enterica and analyze the quantitative contamination level of Salmonella enterica in raw pork samples from farmer′s markets in Chengdu. Based on qualitative detection standard method of Salmonella enterica in China (GB 4789.4-2016) and the quantitative detection method of FSIS in the United States (MLG 4.08 and MLG appendix 2.05 MPN), the selective enrichment broth, screening plate, identification method and quantitative dilution ratio in quantitative detection of Salmonella enterica were optimized using 70 samples of raw pork. The optimized method compared by student′s t-test was used to detect 40 samples of raw pork collected from farmer′s markets in Chengdu from June to October 2020. For isolation of Salmonella from raw pork samples, the coincidence degree of TTB enrichment solution was significantly higher than that of RV enrichment solution (0.93±0.32 vs 0.35±0.62, t=8.324, P=0.001) and the consistency of suspicious colonies screened by XLT4 plate was significantly higher than that of Salmonella chromogenic medium (0.77±0.09 vs 1.00±0.00, t=2.971, P =0.017). The MPN method used 4 successive gradient dilutions, namely 12 tube method, could obtain more accurate quantitative value for Salmonella enterica. The combined use of selective enrichment broth TTB, XLT4 plate, Real-time PCR and MALDI-TOF mass spectrometry could get better results for screening and identifying Salmonella enterica. The detection rate for Salmonella enterica isolated from raw pork in farmer′s markets was 92.5% (37/40). The most of the Salmonella positive samples (83.8%, 31/37) were detected with a contamination level ranged from 0.1 to 55 MPN/g. The optimized quantitative detection method for Salmonella enterica in raw pork in this study can effectively screen the target bacteria and obtain more accurate quantitative value.

In the past ten years, the research and application of microbiome has continued to increase. The microbiome has gradually become the research focus in the fields of life science, environmental science, and medicine. Meanwhile, many countries and organizations around the world are launching their own microbiome projects and conducting a multi-faceted layout, striving to gain a strategic position in this promising field. In addition, whether it is scientific research or industrial applications, there has been a climax of research and a wave of investment and financing, accordingly, products and services related to the microbiome are constantly emerging. However, due to the rapid development of microbiome sequencing and analysis related technologies and methods, the research and application from various countries have not yet unified on the standards of technology, programs, and data. Domestic industry participants also have insufficient understanding of the microbiome. New methods, technologies, and theories have not yet been fully accepted and used. In addition, some of the existing standards and guidelines are too general with poor practicality. This not only causes obstacles in the integration of scientific research data and waste of resources, but also gives related companies unfair competition opportunity. More importantly, China still lacks national standards related to the microbiome, and the national microbiome project is still in the process of preparation. In this context, the experts and practitioners of the microbiome worked together and developed the consensus of experts. It can not only guide domestic scientific research and industrial institutions to regulate the production, learning and research of the microbiome, the application can also provide reference technical basis for the relevant national functional departments, protect the scale and standardized corporate company's interests, strengthen industry self-discipline, avoid unregulated enterprises from disrupting the market, and ultimately promote the benign development of microbiome-related industries.
China ; Consensus ; Humans ; Industry ; Microbiota

Objective To compare the efficiency of domestic MALDI-TOF MS systems Autof MS, Korea Asta MicroIDsys and Bruker Biotyper for common microorganisms identification. Methods This is a methodological comparison study. A total of 169 strains were isolated either from food in our laboratory since 2011 to 2018 or clinical samples in Chinese PLA General Hospital since 2016 to 2018. A total of 39 genus, 95 species were identified through Vitek2 Compact combined with 16S rDNA or ITS sequencing. Among them, a total of 93 Gram-negative bacteria strains, 65 Gram-positive bacteria strains, and 11 yeast strains were identified by three MALDI-TOF MS systems parallelly, while using extended direct smear method for sample preparation. The SPSS 18.0 software was used for data Statistical analysis. Results By Mass spectrometry identification, when 169 strains were at the species level confidence score and acceptable score level, 91.12％ (154/169) was correctly identified to species level by Autof MS system, 86.39％ (146/169) by ASTA MS system, and 81.66％ (138 / 169) by Bruker Biotyper MS system. The difference of identification accuracy to species level between Autof MS and Bruker Biotyper MS was statistically significant. Besides, the accuracy of genus identi fi cation was 98.82％ (167 / 169) by Autof MS mass spectrometry system and 97.04％ (164 / 169) by both ASTA MicroIDsys and Bruker Biotyper mass spectrometry system. The differences of identification accuracy to genus level among the three MS systems were not significant. Conclusions All of the three MS systems have good identification capability for common microorganisms. Autof MS systems performed slightly better than Bruker Biotyper MS systems in species level identification.

BACKGROUND: The complicated localization of intramedullary nails and osteotomy more dependent on surgeons' experience limit the application of conventional total knee arthroplasty (TKA). The occurrence of three-dimensional (3D) printing technology can achieve precise localization and osteotomy in TKA.OBJECTIVE: To explore the effectiveness of 3D printing technology-aided TKA versus conventional TKA for genu varum.METHODS: Thirty-four patients with genu varum undergoing primary unilateral TKA were recruited and were then divided into two groups (n=17 per group) in accordance with the random number table. One group was treated with TKA with 3D printing guild plate (3D printing group), while the other group received the conventional TKA (conventional group).The intraoperative and postoperative blood loss, operation time, as well as the Hospital for Special Surgery score, range of motion, and lower limb mechanical alignment at 2 weeks postoperatively were compared between two groups.RESULTS AND CONCLUSION: (1) The range of motion of knee in the 3D printing group was larger than that in the conventional group, but had no significant difference at 2 weeks postoperatively (P=0.744). (2) There was no significant difference in the Hospital for Special Surgery scores between two groups at 2 weeks postoperatively (P= 0.532). (3) The postoperative lower limb mechanical alignment showed no significant difference between two groups (t=0.218, P=0.632).(4) The operation time in the 3D printing group was significantly shorter than that in the conventional group (P=0.000). (5) The blood loss in the 3D printing group was significantly less than that in the conventional group (P=0.000). (6) Our findings indicate that 3D printing technology-aided TKA exhibits similar results to the conventional TKA in the Hospital for Special Surgery scores, range of motion, and lower limb mechanical alignment, but it shortens the operation time,reduces the blood loss, and achieves precise osteotomy, which is available for the elderly with poor basic condition, and weak tolerance of surgery.

Caliciviridae Infections ; prevention & control ; therapy ; Disease Outbreaks ; prevention & control ; Humans ; Norovirus ; Practice Guidelines as Topic

OBJECTIVETo elucidate the epidemic condition and molecular subtyping of ciprofloxacin and cefotaxime co-resistant Salmonella Indiana (S. Indiana) isolated from retail chicken carcasses in six provinces of China.

METHODSA total of 2 647 Salmonella strains isolated from retail chicken carcasses collected from six provinces of China were subjected to antimicrobial susceptibility testing. All Salmonella isolates co-resistant to ciprofloxacin and cefotaxime were further characterized by serotyping, extended-spectrum beta-lactamases (ESBLs) producing strains screening and pulsed field gel electrophoresis (PFGE) typing.

RESULTSAmong 2 629 Salmonella isolates tested, 227 (8.52%) isolates were co-resistant to ciprofloxacin and ceftazidime/cefotaxime (Beijing: 11.67% (99/874), Jilin: 8.20% (60/726), Guangdong: 1.39% (7/502), Jiangsu: 15.61% (42/260), Shaanxi: 8.56% (16/186), Inner Mongolia: 0 (0/81)), and 224 of them were identified as S. Indiana. 213 (95.10%) isolates of S. Indiana were ESBLs producing strains. All ciprofloxacin and cefotaxime co-resistant S. Indiana isolates developed a multi-drug resistant profile and 17.86% (40/224) of them were resistant to all antibiotics tested except carbapenems, and 50.89% (114/224) of them resistant to 9 antibiotics, additionally, 25.45% (57/224) of them showed multi-drug resistance to 8 antibiotics. All ciprofloxacin and cefotaxime co-resistant S. Indiana isolates were divided into 32 PFGE clusters and 150 PFGE patterns. Strains of S. Indiana from same or different sampling site and time seemed to either share the same PFGE patterns or be differential to each other in different regions.

CONCLUSIONThe results indicated that chicken carcasses collected from parts of China were heavily contaminated by ciprofloxacin and cefotaxime co-resistant S. Indiana and could serve as an important reservoir of ciprofloxacin and cefotaxime co-resistant Salmonella. Molecular subtyping results indicated that cross contamination or common pollution source might be in these strains.

Animals ; Anti-Bacterial Agents ; pharmacology ; Cefotaxime ; pharmacology ; Chickens ; microbiology ; China ; Ciprofloxacin ; pharmacology ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Food Contamination ; Food Microbiology ; Meat ; microbiology ; Salmonella ; classification ; isolation & purification ; Serotyping ; beta-Lactamases

Objective To reduce experimental costs and improve the utilization of S9, we use spiral coating technique to evaluate the activity of rat liver S9 prepared by combination inducing method as well as to establish cryopreservation method.Methods Using spiral coating technique and Ames test to evaluate the activity of self-made rat liver S9 and commercially available S9 separately.We use glycerinum as protective agent to establish cryogenic storage method, so that S9 can be in liquid form stored at -20 °C in the refrigerator.Results In the Ames assay as well as using spiral coating technique, the number of revertant colonies had dose-response relationship among the dose of S9.When conditions were the same, the number of revertant colonies in positive control was at the approximate level in presense of self-made rat liver S9 and commercially available S9 respectively.When S9 ( concentration of 38%) was added to the amount at 1.48 ~6.62 μL /μL broth dose of bacteria, it can significantly induced Salmonella typhimurium histidine strains TA100, reverse mutation rates were three times more than the control group.Conclusions Spiral coating technique can successfully evaluate the activity of rat liver S9.The inducing method of combination of PB and BF can take the place of the unducing method of PCBs in the preparation of Liver homogenate S9.