MALDI-TOF-MS鉴定2008年辽宁省食源性疾病监测系统检出的沙门菌的初步研究

Discrimination of Salmonella isolated from the foodborne disease monitoring system of Liaoning province in 2008 by MALDI-TOF-MS

目的应用MALDI-TOF-MS技术对2008年辽宁省食源性疾病监测检出的24株沙门菌和2株沙门菌标准菌株进行鉴定,并对其中4种血清型的16株沙门菌进行种水平的鉴定。通过MALDI-TOF-MS的相关性分析,研究MALDI-TOF-MS与血清分型结果的相关性及MALDI-TOF-MS对实验的沙门菌的分型能力。方法考察并确定既适合菌株生长又适宜MALDI-TOF-MS分析的沙门菌培养基后,应用MALDI-TOF-MS的相关软件对沙门菌进行数据采集和图谱比对,所得鉴定结果与血清分型结果进行比较。对属于4个种的4株沙门菌的蛋白峰信息进行比较分析。通过生化鉴定及MALDI-TOF-MS的聚类分析及主成分分析讨论4株肠炎沙门菌同源关系。结果 MALDI-TOF-MS技术分别在属和种的水平上准确鉴定了沙门菌株,并且在种的鉴定水平上与血清分型结果具有极大相关性。MALDI-TOF-MS区分了属于4个种的4株沙门菌的蛋白峰之间的微小差异。而且,对相同血清型的4株肠炎沙门菌的聚类分析及主成分分析显示出其同源程度的差异。结论 MALDI-TOF-MS技术在属水平上鉴定沙门菌具有很高的准确性,在种水平上的鉴定也有着很好的应用前景。MALDI-TOF-MS技术可能为沙门菌分型溯源提供一种新的手段。

Objective A rapid method based on matrix-assisted laser desorption ionization-time of flight mass spectrometry（MALDI-TOF-MS） for the identification of intact bacterial cells was used for the discrimination of Salmonella strains at genus and species level.The aim of this study was to discuss the relationship of the result from MALDI-TOF-MS analysis and serotyping,and the typing ability of MALDI-TOF-MS to Salmonella strains through relative soft wares.Methods Twenty-four Salmonella strains isolated from the Foodborne Disease Monitoring System of Liaoning Province in 2008 and 2 standard strains purchased from ATCC were used in the study.Sixteen Salmonella strains belonging to four serotypes were applied on MALDI-TOF-MS for the identification of Salmonella at species level.A detailed analysis on mass spectrometric profiles and the information of protein peaks were obtained from four different Salmonella species.The homology of these 4 Salmonella enteritidis was also discussed through biochemical test and relative analysis with MALDI-TOF-MS.After an optimum medium suitable for both the growth of Salmonella strains and MALDI-TOF-MS analysis was selected,26 Salmonella strains were tested to verify the accuracy of MALDI-TOF-MS in genus levels,and 16 of 26 Salmonella species,which belonging to 4 different serotypes,were also typed in species level.Relative software was used to collect data and compare the peaks obtained from four Salmonella species.The biochemical test,MALDI-TOF-MS dendrogram analysis and Principal Component analysis were adopted to confirm the homologous diversity of 4 Salmonella enteritidis from different locations.Results The identification results of MALDI-TOF-MS on 26 Salmonella in genus level were matched with their classic biochemical identification results,and the discrimination results of 16 Salmonella in species level were also matched with their serotypes.Slight differences among 4 Salmonella species were also discovered through the peaks lists of them by MALDI-TOF-MS successfully.Furthermore,the homologous diversity of 4 Salmonella enteritidis was demonstrated obviously.Conclusion MALDI-TOF-MS can be used to discriminate Salmonella strains used in this study rapidly and exactly on genus level.It has also a potential ability on typing Salmonella species and will be a powerful tool for rapid and accurate identification of foodborne pathogens.