MALDI-TOF MS自建库在红色毛癣菌感染中的临床快速诊断价值

目的建立并评价实验室自建的红色毛癣菌基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)数据库的可行性。方法将红色毛癣菌标准菌株ATCC 28188用沙保罗葡萄糖琼脂(SDA)平板28℃培养5d,分别用双甲酸夹心法和甲酸提取法作为蛋白提取方法,利用MALDI-TOF MS对标准菌株进行质谱数据采集,建立2种不同蛋白提取方法的菌株数据库"双甲酸夹心法自建库"和"甲酸提取法自建库";并用2种蛋白提取方法对21株红色毛癣菌临床分离株进行蛋白提取后,分别选取"双甲酸夹心法自建库+Bruker商品库"、"甲酸提取法自建库+Bruker商品库"和"Bruker商品库"做质谱鉴定,从而对各数据库的鉴定效果进行评价。结果"甲酸提取法自建库+Bruker商品库"对21株红色毛癣菌临床分离株的鉴定得分显著高于其余两组,差异有统计学意义(P<0.05),匹配率为21/21;"Bruker商品数据库"与"Bruker商品数据库+双甲酸夹心法自建库"的鉴定得分比较差异无统计学意义(P>0.05)。结论本实验室建立的"甲酸提取法自建库+Bruker库"对红色毛癣菌的鉴定能力好,适用于临床微生物实验室。与待测菌统一培养条件所建立的数据库丰富了原有的数据库信息,使待测菌的鉴定更为准确。双甲酸夹心法操作简便,但对红色毛癣菌蛋白提取的效果欠佳。

Diagnostic value of MALDI-TOF MS self-built library in Trichophyton rubrum infection

Objective To establish and evaluate the feasibility of a laboratory-built matrix of Trichophyton rubrum matrix-assisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF MS).Methods The standard strain of Trichophyton rubrum ATCC 28188 was cultured at 28℃for 5 don sepalol glucose agar(SDA)plate.The protein was extracted by the method of double formic acid sandwich and formic acid extraction respectively.The protein was extracted by MALDI-TOF MS was used to collect the mass spectrum data of standard strains,and two kinds of strain databases of different protein extraction methods were set up,which were "self-built library of dicarboxylic acid sandwich method" and "self-built Library of formic acid extraction method".After protein extraction of 21 clinical isolates of Trichophyton rubrum by two methods,we selected "self built library of dicarboxylic acid sandwich method+Bruker commercial library" ", self built library of formic acid extraction method+Bruker commercial library" and " Bruker commercial library" for mass spectrometry identification,so as to evaluate the identification effect of each database.Results The score of "self built library of formic acid extraction method+Bruker commercial library" of 21 clinical isolates of Trichophyton rubrum was significantly higher than that of the other two groups(P<0.05),the matching rate was 21/21;there was no significant difference between " Bruker commercial library" and "self built library of dicarboxylic acid sandwich method+Bruker commercial library"(P<0.05).Conclusion The "self built library of formic acid extraction method+Bruker commercial library" by this laboratory has a good ability to identify Trichophyton rubrum,which is suitable for clinical microbiology laboratory.The database established by the unified culture conditions with the bacteria to be tested enriches the original database information and makes the identification of the bacteria to be tested more accurate.The double formic acid sandwich method is easy to operate,but the effect of protein extraction of Trichophyton rubrum is not good.