常见致病菌MALDI-TOF质谱分析影响因素的研究

Research to the influential factors of MALDI- TOF spectrometry for common pathogens

目的研究影响常见食源性疾病致病菌MALDI-TOF质谱分析的关键因素。方法分析鉴定不同时间段内的6株致病菌,比较检出峰的荷质比、峰值及特征峰的差异。结果检出的致病性大肠埃希菌、肺炎克雷伯菌和金黄色葡萄球菌在最适培养基和检测时间上具有差异,金黄色葡萄球菌对质谱分析的时效性等要求较低,易检出。抑制状态的致病菌具有特殊质谱峰,延长培养时间导致部分检出率下降,质谱特征峰缺失,峰值显著减弱。肺炎克雷伯菌的质谱兼容性低,菌株间差异大,使用血平板可以提高检出率。结论质谱鉴定对培养基和培养时间的选择具有致病菌种属特异性,微生物生理状态同样影响着质谱结果,分析抑制状态下致病菌的特有生物标志峰有利于提高质谱分析的普适性。

Objective To analyze the influential factors of MALDI- TOF spectrometry for the detection of common foodborne diseases pathogenic bacteria at different conditions of cultures. Methods 6 pathogens at different culture conditions were identified,the difference of peak load ratio,peak value and characteristic peak of the detected peaks were analyzed and compared.Results The optimum conditions and analysis period for mass spectrum of Pathogenicity escherichia coli,Klebsiella pneumonia and Staphylococcus aureus were distinguishing. Staphylococcus aureus was easy to check out. The repressive pathogens had its independent characteristic peak. Pathogens detection rate declined when the culture time was prolonged. Meanwhile,the mass spectrum characteristic peak number decreased and peak value declined. The low mass of Klebsiella pneumoniae was low,and the difference between the strains was large,and the detection rate was improved by using the blood plate. Conclusion The selection of culture medium and time of culture has the characteristics of pathogenic bacteria. Microbial physiological status also affected the results of mass spectrometry. Analysis of the characteristics of specific biomarkers in the inhibition of the pathogen is beneficial to improve the universality of the mass spectrometry analysis.