基于MALDI-TOF MS技术对食源性大肠埃希菌O157:H7的分型

Classification of Food-Borne Escherichia coli O157:H7 Based on MALDI-TOF MS

建立基于基质辅助激光解吸电离飞行时间质谱技术鉴定大肠埃希菌O157:H7分型的方法,并利用66株大肠埃希菌进行方法验证。通过对不同培养基、不同时间大肠埃希菌标准菌株的MALDI-TOF MS质谱图进行比较,选取最优培养基和培养时间;对66株大肠埃希菌在最优培养基和培养时间状态下进行MALDI-TOF建库,通过对比蛋白指纹图谱、聚类分析对大肠埃希菌O157:H7进行鉴定。结果表明,在血琼脂平板上生长的大肠埃希菌峰质量最高,大肠埃希菌O157:H7在m/z 9060处出现峰缺失现象。聚类分析结果中,不同食品来源大肠埃希菌出现聚集现象,大肠埃希菌O157:H7聚集紧密。可通过MALDI-TOF MS技术m/z 9060峰缺失和聚类分析方法区分大肠埃希菌O157:H7与非O157:H7血清型大肠埃希菌。

Matrix-assisted laser desorption ionization-time of flight mass spectrometry technique that was used to identify the typing method of Escherichia coli O157:H7,was established,and 66 strains of Escherichia coli were used for method verification.The MALDI-TOF MS of Escherichia coli was compared on different medium and in different time to select the optimal medium and culture time.The MALDI-TOF database was established for 66 strains of Escherichia coli under optimal culture medium and culture time,and Escherichia coli O157:H7 was identified by comparison of mass spectrometry peak and cluster analysis.The results showed that Escherichia coli O157:H7 grew on the blood agar had the best peak.Escherichia coli O157:H7 appeared peak missed at m/z 9060.The clustering analysis results showed that Escherichia coli from different food sources appear gathered and the O157:H7 gathered together closely.Escherichia coli O157:H7 can be identified by MALDITOF MS technique with m/z 9060 peak missed,and the closely related Escherichia coli O157:H7 can be identified by cluster analysis.