Objective To establish a molecular typing system of Staphylococcus aureus by using resolution melting for food-poi-soning fast tracing.Methods Primers were designed and synthesized according to the literature of VNTR in Staphylococcus au-reus ,and were used to perform molecular typing on the strains which had detected by PFGE,then 4 types of VNTRs were with higher discriminatory power were selected.On this basis,we established a molecular typing system for the detection of 59 Staphy-lococcus aureus isolated from food poisoning.Results The molecular typing system has good precision for detection.The standard deviation(s)of within-batch repetitive experiments were 0.03 -0.05 ℃,between-batch repetitive experiments were 0.04 -0.06℃,between-day repetitive experiments were 0.04-0.06 ℃.At the same time,the 59 strains of Staphylococcus aureus were divided into 19 types which were 11 epidemic clones and 8 sporadic clones.The correlation coefficient of Simpson was 0.916 4.Conclusion The molecular typing system for Staphylococcus aureus based on resolution melting was simple,fast and repeatable.It can be ap-plied to fast tracing and screen of Staphylococcus aureus in food poisoning.

Objective:To investigate the clinical value of abdominal adipose volume in predicting early tumor recurrence after resection of hepatocellular carcinoma (HCC).Methods:The retrospective case-control study was conducted. The clinicopathological data of 132 HCC patients with tumor diameter ≤5 cm who were admitted to The First Affiliated Hospital of Army Medical University from December 2017 to October 2019 were collected. There were 110 males and 22 females, aged (51±4)years. All patients underwent resection of HCC. Preoperative computer tomography scanning was performed and the visceral and subcutaneous fats of patients were quantified using the Mimics Research 21.0 software. Based on time to postoperative tumor recurrence patients were divided to two categories: early recurrence and non-early recurrence. Observation indicators: (1) consistency analy-sis; (2) analysis of factors influencing early tumor recurrence after resection of HCC and construction of prediction model. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribu-tion were represented as M( Q1,Q3) or M(range), and comparison between groups was conducted using the Mann-Whitney U test. Count data were expressed as absolute numbers, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Consistency analysis was conducted using the intragroup correlation coefficient (ICC) test. Multivariate analysis was performed using the binary Logistic regression model forward method. Independent risk factors influencing early tumor recurrence after resection of HCC were screened. The area under curve (AUC) of receiver operating characteristic (ROC) curve was applied to select the optimal cut-off value to classify high and low risks of recurrence. The Kaplan-Meier method was used to draw survival curve and calculate survival time. The Log-Rank test was used for survival analysis. Results:(1) Consistency analysis. The consistency ICC of abdominal fat parameters of visceral fat volume (VFV), subcutaneous fat volume, visceral fat area, and subcutaneous fat area measured by 2 radiologists were 0.84, 1.00, 0.86, and 0.94, respectively. (2) Analysis of factors influencing early tumor recurr-ence after resection of HCC and construction of prediction model. All 132 patients were followed up after surgery for 662(range, 292-1 111)days. During the follow-up, there were 52 patients with non-early recurrence and 80 patients with early recurrence. Results of multivariate analysis showed that VFV was an independent factor influencing early tumor recurrence after resection of HCC ( odds ratio=4.07, 95% confidence interval as 2.27-7.27, P<0.05). The AUC of ROC curve based on VFV was 0.78 (95% confidence interval as 0.70-0.85), and the sensitivity and specificity were 72.2 % and 77.4 %, respectively. The optimal cut-off value of VFV was 1.255 dm 3, and all 132 patients were divided into the high-risk early postoperative recurrence group of 69 cases with VFV >1.255 dm 3, and the low-risk early postoperative recurrence group of 63 cases with VFV ≤1.255 dm 3. The disease-free survival time of the high-risk early postoperative recurrence group and the low-risk early post-operative recurrence group were 414(193,702)days and 1 047(620,1 219)days, showing a significant difference between them ( χ2=31.17, P<0.05). Conclusions:VFV is an independent factor influen-cing early tumor recurrence of HCC after resection. As a quantitative indicator of abdominal fat, it can predict the prognosis of HCC patients.

Objective To analyze the etiological characteristics,virulence genes and plasmids that carrying diarrhea-causing Proteus mirabilis and to assess their relationship with drug resistance and pathogenicity. Methods Proteus mirabilis coming from six different sources (food poisoning,external environment and healthy people) were analyzed biochemically,on related susceptibility and pulsed-field gel electrophoresis (PFGE). Virulence genes were detected by PCR. Plasmids were extracted and sequenced after gel electrophoresis purification. Results The biochemical characteristics of Proteus mirabilis from different sources seemed basically the same,and each of them showed having common virulence genes,as ureC,rsmA,hpmA and zapA. However,the PFGE patterns and susceptibility of these strains were different,so as the plasmids that they carried. Plasmid that presented in the sequenced strain showed that the 2 683 bp length plasmid encodes qnrD gene was associated with the quinolone resistance. Conclusion Etiological characteristics and molecular characteristics of Proteus mirabilis gathered from different sources,were analyzed. Results indicated that traditional biochemical analysis and common virulence gene identification might be able to distinguish the strains with different sources. However,PFGE and plasmids analysis could distinguish the sources of strains and to identify those plasmids that commonly carried by the drug-resistant strains. These findings also provided theoretical basis for further study on the nature of resistance and pathogenicity in Proteus mirabilis.

OBJECTIVETo understand the epidemiologic and etiologic characteristics of diarrheagenic Escherichia (E.) coli infections in Shenzhen.

METHODSStool samples were collected from acute diarrheal patients in four sentinel hospitals in Shenzhen and diarrheagenic E. coli strains were isolated and identified with multiplex real-time PCR. Serotyping and pulsed-field gel electrophoresis (PFGE) typing were conducted for the diarrheagenic E. coli isolates.

RESULTSA total of 74 diarrheagenic E. coli strains were isolated from 1 823 stool samples (4.06%). The patients were mainly young children aged <3 years and adults aged 20-39 years, and the infections mainly occurred during May-September of a year. Enterotoxigenic E. coli (ETEC) and enteropathognic E. coli (EPEC) were predominant (45.9% and 31.1%). Serogroups and PFGE patterns varied among the diarrheagenic E. coli isolates. However, serogroup O159 were predominant in ETEC and there were 5 clusters with ≥2 strains sharing same PFGE patterns.

CONCLUSIONSETEC and EPEC were predominant in diarrheagenic E. coli strains isolated from diarrheal patients in Shenzhen. Age and season specific characteristics of diarrheagenic E. coli infections were observed. The serotypes and PFGE patterns of diarrheagenic E. coli strains varied. Close attention should be paid to the possible ETEC outbreak.

Adult ; Child, Preschool ; China ; epidemiology ; Diarrhea ; epidemiology ; microbiology ; Disease Outbreaks ; Electrophoresis, Gel, Pulsed-Field ; Enterotoxigenic Escherichia coli ; classification ; isolation & purification ; Escherichia coli Infections ; epidemiology ; Humans ; Real-Time Polymerase Chain Reaction ; Serotyping ; Young Adult

OBJECTIVETo analyze the etiological characteristics, virulence genes and plasmids that carrying diarrhea-causing Proteus mirabilis and to assess their relationship with drug resistance and pathogenicity.

METHODSProteus mirabilis coming from six different sources (food poisoning, external environment and healthy people) were analyzed biochemically, on related susceptibility and pulsed-field gel electrophoresis (PFGE). Virulence genes were detected by PCR. Plasmids were extracted and sequenced after gel electrophoresis purification.

RESULTSThe biochemical characteristics of Proteus mirabilis from different sources seemed basically the same, and each of them showed having common virulence genes, as ureC, rsmA, hpmA and zapA. However, the PFGE patterns and susceptibility of these strains were different, so as the plasmids that they carried. Plasmid that presented in the sequenced strain showed that the 2 683 bp length plasmid encodes qnrD gene was associated with the quinolone resistance.

CONCLUSIONEtiological characteristics and molecular characteristics of Proteus mirabilis gathered from different sources, were analyzed. Results indicated that traditional biochemical analysis and common virulence gene identification might be able to distinguish the strains with different sources. However, PFGE and plasmids analysis could distinguish the sources of strains and to identify those plasmids that commonly carried by the drug-resistant strains. These findings also provided theoretical basis for further study on the nature of resistance and pathogenicity in Proteus mirabilis.

Diarrhea ; microbiology ; Drug Resistance, Bacterial ; Genes, Bacterial ; Humans ; Plasmids ; genetics ; Proteus mirabilis ; genetics ; pathogenicity ; Virulence Factors ; genetics