Perifosine inhibits biofilm formation of Pseudomonas aeruginosa by interacting with PqsE protein / 中华预防医学杂志

To explore the biofilm inhibitory efficacy of perifosine against Pseudomonas aeruginosa (P. aeruginos) and its mechanisms. Twenty-fourwell plate was used to form biofilms at the bottom and crystal violet staining was used to determine the biofilm inhibitory effects of perifosine against P. aeruginosa, the wells without perifosine was set as control group. Glass tubes combined with crystal violet staining was used to detect the gas-liqud interface related bioiflm inhibitory effects of perifosine, the wells without perifosine was set as control group. Time-growth curved was used to detect the effects of perifosine on the bacteial planktonic cells growth of P. aeruginosa, the wells without perifosine was set as control group. The interaction model between perifosine and PqsE was assessed by molecular docking assay. The inhibitory effects of perifosine on the catalytic activity of PqsE was determined by detection the production of thiols, the wells without perifosine was set as control group. Binding affinity between perifosine and PqsE was detected by plasma surface resonance. The biofims at the bottom of the microplates and air-liquid interface were effectively inhibited by perifosine at the concentration of 4-8 μg/ml. There was no influence of perifosine on the cells growth of P. aeruginosa. The resuts of molecular docking assay indicates that perifosine could interacted with PqsE with the docking score of -10.67 kcal/mol. Perifosine could inhibit the catalytic activity of PqsE in a dose-dependent manner. The binding affinity between perifosine and PqsE was comfirmed by plasma surface resonance with KD of 6.65×10-5mol/L. Perifosine could inhibited the biofilm formation of P. aeruginosa by interacting with PqsE.

Clinical distribution and heterogeneity of antimicrobial resistance of Pseudomonas aeruginosa / 中国感染控制杂志

Objective To understand clinical distribution and antimicrobial resistance characteristics of Pseudomonas aeruginosa(P.aeruginosa)isolated from hospitalized patients, so as to provide reference for the empiric use of antimicrobial agents and control of healthcare-associated infection(HAI).Methods Clinical distribution and antimicrobial susceptibility testing results of P.aeruginosaisolated from patients in a hospital between 2012 and 2016 were analyzed retrospectively, statistical analysis were conducted based on different wards, specimen types and age groups.Results A total of 2 432 strains of P.aeruginosa were isolated from2012 to 2016, most of which were isolated from intensive care unit(ICU)(n=727, 29.89％), the main specimen was sputum(n=2 064, 84.87％). Resistance rates of P.aeruginosa to other antimicrobial agents except piperacillin/tazobactam in each year from 2012 to 2016 were significantly different(all P＜0.05).Resistance to piperacillin, ceftazidime, cefepime, imipenem, meropenem, levofloxacin, and ciprofloxacin decreased after peaked in2014;resistance rates to amikacin, gentamicin, and tobramycin were all low, showing decreased trend year by year(all P＜0.05).Except resistance rates to cefepime and tobramycin, resistance rates of P.aeruginosafrom sputum specimen were all higher than other specimens(all P＜0.05).Resistance rates of P.aeruginosaisolated from patients aged≥65 years to most antimicrobial agents were significantly higher than those isolated from patients aged＜65 years(all P＜0.05).Except resistance rates to gentamicin and tobramycin, resistance rates of P.aeruginosaisolated from ICU were higher than those isolated from other departments, which were 7.71％-66.02％.Resistance rate of P.aeruginosaisolated from department of surgery were relatively low, which were 1.69％-11.86％.Conclusion Clinical distribution of antimicrobial resistance of P.aeruginosais obviously heterogeneity, empiric antimicrobial use and formulation of HAI monitoring measures should be based on the data of antimicrobial resistance in different wards, different infection sites, and different age.

Determination of related substances in carbazochrome sodium sulfonate injection by HPLC / 中国药学杂志

OBJECTIVE: To develop a method for separating and determining the related substances in carbazochrome sodium sulfonate injection. METHODS: HPLC Gradient elution was performed on an HP-ODS Hypersil colum. The mixture of 0.01 mol·L-1 phosphate buffer (pH 3.0) and acetonitrile (94:6) was used as mobile phase A, and acetonitrile as mobile phase B. The flow rate was 1.0 mL·min-1, the detection wavelength was set at 220 nm. RESULTS: After being treated with acid, base, heat and oxidation, carbazochrome sodium sulfonate underwent more or less degradation, the degradation products could be detected by the proposed method. Among the practical carbazochrome sodium sulfonate injection and carbazochrome sodium sulfonate and sodium choloride injection samples, the thermo degradation impurities but no impurities resulted from other treatments were detected in carbazochrome sodium sulfonate injections and carbazochrome sodium sulfonate sodium chloride injections. CONCLUSION: The proposed method can be used to separate and determine the related substances in carbazochrome sodium sulfonate injection, and is suitable for the quality control of this drug.

Determination of two saponins in Tupistra chinensis rhizomes by RP-HPLC / 中国中药杂志

<p><b>OBJECTIVE</b>To develog an HPLC method determination of two new saponins in the dried rhizomes of Tupistra chinensis.</p><p><b>METHOD</b>The analysis was performed on YMC-Pack ODS-AQ (4.6 mm x 250 mm, 5 microm) eluted with of acetonitrile and waterin gradient mode. The conentration of acetonitrile in the mobile phase changes from 10% to 100% within 85 minutes. The detection wavelength was set at 203 nm. The flow rate was 1.00 mL x min(-1) and column temperature was set at 30 degrees C.</p><p><b>RESULT</b>The linear relationships of two authentic saponins were determined within the range from 7.55 microg to 60.40 microg (r=0.9996) and 8.00 microg to 48.00 microg (r=0.9996), respectively. Using the method above, the contents of two saponins were determined as 0.261% and 0.242%, with the recoveries as 98.6% and 98.3% with RSD 1.7% and 1.7%, respectively.</p><p><b>CONCLUSION</b>A convenient and reliable method was developed to determine the content of two saponins in the dried rhizomes of Tupistra chinensis.</p>