OBJECTIVE To determine the prevalence of gene qnrA in clinical isolates of Enterobacteriaceae,phenotypes of drug resistance and their molecular mechanisms.METHODS Totally 332 isolates of Enterobacteriaceae from Shenzhen City from 2003 to 2004 were screened for the presence of qnrA by PCR.The gyrA,and parC genes the genes,coding ESBLs and AmpC were amplified and sequenced.K-B method,the international standard plate dilute method and E-test were used to detect MIC of the isolates with qnrA.ESBLs were distinguished by the phenotypic confirmatory test.RESULTS The incidence of qnrA in clinical isolates was 3.9%,the highest incidence of 15.6% occurred in Enterobacter cloacae.The clinical isolates were multi-resistant.gyrA And parC mutation associated with quinolone resistance and ESBLs producing was confirmed in most of the isolates with qnrA.qnrA Was embedded in In37 or InX classified to Sul1 type class Ⅰ integrons.CONCLUSIONS Gene qnrA located in plasmids is an important mechanism mediated quinolone resistance in Enterobacteriaceae.The potential horizontal transferability and multiple resistance hereditary background in these isolates challenge the anti-infective therapy.

Objective To investigate the therapeutic effect of low-carbohydrate diet and online lifestyle intervention on patients with lean nonalcoholic fatty liver disease(NAFLD).Methods This study was conducted among 53 patients with lean NAFLD who attended Department of Infectious Diseases in Peking University Shenzhen Hospital and Shenzhen Qianhai Shekou Free Trade Zone Hospital from December 2019 to March 2021,and the patients were given low-carbohydrate diet for calorie restriction[total calorie intake was calculated based on basal metabolic rate(BMR)and physical activity level(PAL)and was restricted within(BMR×95%×PAL-1 000)kcal to(BMR×95%×PAL-500)kcal,and carbohydrate ratio fluctuated between 10%and 55%]and lifestyle interventions for 8 weeks.An online software was used for supervision and follow-up,and the patients were observed in terms of treatment outcome and safety.The patients were compared in terms of controlled attenuation parameter(CAP),liver stiffness measurement(LSM),Anthropometric parameters,blood biochemistry,urinary protein,and urine ketone body before and after intervention.The patients were followed up after 1 year to measure body weight and body mass index(BMI).The independent-samples t test was used for comparison of normally distributed continuous data between two groups,and the paired-sample Wilcoxon rank-sum test was used for comparison of non-normally distributed continuous;the chi-square test was used for comparison of categorical data between groups.Results After 8 weeks of intervention,CAP decreased from 304.47±31.91 db/m to 242.43±26.74 db/m,LSM decreased from 7.43±2.41 kPa to 6.36±1.79 kPa,and body weight decreased from 64.29±7.37 kg to 60.24±7.08 kg(t=11.25,3.72,and 14.07,all P<0.001).Of all patients,25(47.2%)had disappearance of fatty liver,and abnormal LSM in 12 patients(63.2%)returned to normal;52 patients(98.1%)had a mean reduction of 4.05±2.32 kg in body weight.The degree of reduction in CAP increased with the degree of reduction in body weight.After intervention,there were significant reductions in BMI,waist circumference,hip circumference,alanine aminotransferase(ALT),aspartate aminotransferase(AST),gamma-glutamyl transpeptidase(GGT),uric acid,fasting blood glucose,triglyceride(TG),total cholesterol(TC),and low-density lipoprotein(LDL)and a significant increase in high-density lipoprotein(t=12.85,13.77,10.28,7.64,6.21,8.35,6.83,6.31,7.4,4.97,5.95,and-2.21,all P<0.05).The patients with abnormal ALT,AST,GGT,uric acid,fasting blood glucose,TG,TC,and LDL at baseline which returned to normal after intervention accounted for 75%,100%,81.8%,57.1%,100%,66.7%,73.5%,and 85.3%,respectively.There were no significant changes in blood urea nitrogen,serum creatinine,urine protein,and urine ketone body(all P>0.05).There was no rebound in body weight and BMI after 1 year of follow-up(P>0.05).There were no gastrointestinal reactions during intervention or follow-up.Conclusion Low-carbohydrate diet and lifestyle intervention can improve liver fat content,liver function,and blood lipid parameters in patients with lean NAFLD,with good safety.