MALDI-TOF MS在儿童血培养阳性病原菌快速鉴定中的应用

目的建立快速、准确的儿童血培养阳性病原菌鉴定方法,缩短血流感染鉴定时间,评估临床试验可行性。方法运用分离胶法提取阳性血培养瓶中富集的菌落,利用基质辅助激光解析电离飞行时间质谱分析(MALDI-TOF MS)对经过一系列前处理后的血培养阳性标本进行鉴定,并与病原菌纯培养鉴定后的结果对比,比较MALDI-TOF MS快速鉴定方法的符合率。结果100例血培养阳性样本中,除3例假阳性标本及3例混合感染标本外,以快速鉴定修正后的评分标准,MALDI-TOF MS快速鉴定方法与病原菌纯培养鉴定方法符合率达89.0%(81/91)。革兰阳性球菌、革兰阴性杆菌鉴定符合率分别为96.2%(50/52)、92.6%(25/27);而真菌的符合率不够理想,7株真菌中仅3株鉴定相符、符合率为42.9%。结论儿童血培养阳性标本的MALDI-TOF MS快速鉴定方法,对血流感染中致病菌的鉴定准确率高、耗时短,具有临床应用可行性,可满足临床早期、快速诊断血流感染致病菌的需求,但是对于真菌样本的前处理方法有待提高。

Application of MALDI-TOF MS in rapid identification of positive pathogens from blood culture in Children

Objective To establish a rapid and accurate method for the identification of pathogens from positive blood culture in children,shorten the identification time ofbloodstream infection,and evaluate the feasibility of clinical trials.Methods The bacteria were enriched and purified directly from positive blood culture bottle by separation gel tube.Pre-treated blood culture positive samples were identified using MALDI-TOF MS.The coincidence rate of MALDI-TOF MS rapid identification was compared with pure culture of pathogenic.Results Among 100 blood culture positive samples,except 3 false positive samples and 3 mixed infection samples,the total coincidence rate of MALDI-TOF MS and pure culture was 89.0%by using the revised scoring standard for rapid identification,while Gram-positive cocci and Gramnegative bacilli were 96.2%(50/52)and 92.6%(25/27)respectively,only 3 of 7 fungi were identified consistent(42.9%)according to the adjusted scoring criteria.Conclusion The rapid identification method of MALDI-TOF MS for positive samples from blood culture of children has high accuracy and short time consumption for the identification of pathogenic bacteria in bloodstream infection,which is feasible for clinical application,and can meet the requirements of early and rapid diagnosis of pathogenic bacteria in bloodstream infection.However,the pretreatment for fungal samples needs to be improved.