CHCA as a matrix facilitates the ionization of proteins and peptides in a matrix-assisted laser desorption/ionization(MALDI) time-of-flight(TOF) mass spectrometer. The matrix itself also ionizes and so do its adducts....CHCA as a matrix facilitates the ionization of proteins and peptides in a matrix-assisted laser desorption/ionization(MALDI) time-of-flight(TOF) mass spectrometer. The matrix itself also ionizes and so do its adducts. Matrix clusters and adducts interfere with peptide ionization and peptide mass spectrum interpretation, especially at low sample concentrations and within m/z 500-1 000 range. These matrix adducts, especially within m/z 500-1 000, are significantly reduced with addition of ammonium citrate, ammonium sulfate, ammonium benzoate, ammonium bicarbonate, ammonium citrate and potassium dihydrogen phosphate to the matrix and the samples were deposited onto the MALDI target. The reduction of matrix adducts improves peptide ionization and signal-to-noise ratio, which enhances the reliability of database searching.展开更多
目的:用基质辅助激光解吸电离飞行时间质谱(matrix-assisted laser desorption/ionization-time of flight mass spectrometry,MALDI-TOF MS)检测碳青霉烯耐药的肺炎克雷伯菌(carbapenem-resistant Klebsiella pneumoniae,CRKp)同源性,...目的:用基质辅助激光解吸电离飞行时间质谱(matrix-assisted laser desorption/ionization-time of flight mass spectrometry,MALDI-TOF MS)检测碳青霉烯耐药的肺炎克雷伯菌(carbapenem-resistant Klebsiella pneumoniae,CRKp)同源性,并与脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)和多位点序列分型(multilocus sequence typing,MLST)两种检测方法进行对比,探讨质谱在日常工作中的应用价值。方法:选取2017年10—12月从河南科技大学第一附属医院院患者分离的以及ICU环境采集的碳青霉烯耐药肺炎克雷伯菌10株,检测8种耐药基因:blaTEM、blaSHV、blaCTX-M、blaKPC、blaIMP、blaNDM、blaVIM、blaOXA。采用PFGE、MLST和MALDI-TOF MS 3种方法对这些菌株进行同源性分析。结果:PFGE证实10株CRKp均为同一克隆株的传播,ST型同属于ST11。MALDI-TOF MS经过对细菌进行聚类分析和主成分分析可以区分不同型别肺炎克雷伯菌,对同型肺炎克雷伯菌(Klebsiella pneumonia,Kp)的同源性检测在80%左右。结论:MALDI-TOF MS在肺炎克雷伯菌的同源性检测方面可以应用于院内爆发局部感染的监测,与PFGE和MLST两种方法检测结果一致,但需要尽快建立规范的判断标准。展开更多
文摘CHCA as a matrix facilitates the ionization of proteins and peptides in a matrix-assisted laser desorption/ionization(MALDI) time-of-flight(TOF) mass spectrometer. The matrix itself also ionizes and so do its adducts. Matrix clusters and adducts interfere with peptide ionization and peptide mass spectrum interpretation, especially at low sample concentrations and within m/z 500-1 000 range. These matrix adducts, especially within m/z 500-1 000, are significantly reduced with addition of ammonium citrate, ammonium sulfate, ammonium benzoate, ammonium bicarbonate, ammonium citrate and potassium dihydrogen phosphate to the matrix and the samples were deposited onto the MALDI target. The reduction of matrix adducts improves peptide ionization and signal-to-noise ratio, which enhances the reliability of database searching.
文摘目的:用基质辅助激光解吸电离飞行时间质谱(matrix-assisted laser desorption/ionization-time of flight mass spectrometry,MALDI-TOF MS)检测碳青霉烯耐药的肺炎克雷伯菌(carbapenem-resistant Klebsiella pneumoniae,CRKp)同源性,并与脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)和多位点序列分型(multilocus sequence typing,MLST)两种检测方法进行对比,探讨质谱在日常工作中的应用价值。方法:选取2017年10—12月从河南科技大学第一附属医院院患者分离的以及ICU环境采集的碳青霉烯耐药肺炎克雷伯菌10株,检测8种耐药基因:blaTEM、blaSHV、blaCTX-M、blaKPC、blaIMP、blaNDM、blaVIM、blaOXA。采用PFGE、MLST和MALDI-TOF MS 3种方法对这些菌株进行同源性分析。结果:PFGE证实10株CRKp均为同一克隆株的传播,ST型同属于ST11。MALDI-TOF MS经过对细菌进行聚类分析和主成分分析可以区分不同型别肺炎克雷伯菌,对同型肺炎克雷伯菌(Klebsiella pneumonia,Kp)的同源性检测在80%左右。结论:MALDI-TOF MS在肺炎克雷伯菌的同源性检测方面可以应用于院内爆发局部感染的监测,与PFGE和MLST两种方法检测结果一致,但需要尽快建立规范的判断标准。
