金黄色葡萄球菌基质辅助激光解析电离-飞行时间质谱的鉴定与聚类分型

目的 建立基质辅助激光解吸电离-飞行时间质谱法(matrix assisted laser desorption lonization-time of flight mass spectrometer, MALDI-TOF MS)快速鉴定金黄色葡萄球菌(Staphylococcus aureus, S. aureus)并自建数据库, 进行聚类分型。方法 基于MALDI-TOF MS技术, 对经全自动微生物分析仪(VITEK2 COMPACT)鉴定为S. aureus的25株分离株和1株标准菌株(ATCC 25923)进行鉴定。并进一步采集26株S. aureus特征性蛋白质指纹图谱, 使用flex Analysis软件进行分析, 汇总成标准图谱并构建本地分离株S. aureus的鉴定数据库, 命名为Staphylococcus aureus。结果 经标准菌株ATCC 25923验证, 自建数据库对S. aureus鉴定结果的可信度较设备自带数据库明显提高, 鉴定分值由2.251提高到了2.845。自建数据库进一步对26株S. aureus进行聚类分型, 在差异水平100时, 24株不同来源S. aureus被聚类成24个分支, 将食品中不同来源分离的S. aureus分为24个型。结论 MALDI-TOF MS作为一种快速、准确、高通量的全新微生物鉴定技术, 实现了对S. aureus的特异性快速鉴定与分型, 能够满足公共安全卫生、突发食品安全事件和口岸快速通关方面的需求。

Identification and dendrogram of staphylococcus aureus by matrix assisted laser desorption lonization-time of flight mass spectrometery

Objective To establish a matrix assisted laser desorption lonization-time of flight mass spectrometery (MALDI-TOF MS) to rapidly identify Staphylococcus aureus (S. aureus) and build a database for clustering. Methods Based on the MALDI-TOF MS technique, 25 isolates that were identified as S. aureus by automatic microbiology analyzer (VITEK2 COMPACT) and one S. aureus standard strain (ATCC 25923) was detected. The characteristic protein fingerprints of the 26 strains of S. aureus field strains were obtained, analyzed and summarized into standard fingerprints by flex analysis. The self-built database named as Staphylococcus aureus was established based on these data. Results The identification results of ATCC 25923 showed that the self-built database had high reliability for identification of S. aureus comparing to the origin database. The identify score increased from 2.251 to 2.845. On the basis of the information obtained from the self-built database, 26 S. aureus strains were clustered. When the difference level was 100, 24 S. aureus from different sources were clustered into 24 branches and S. aureus from different sources in food was divided into 24 types. Conclusion As a fast, accurate and high throughput bacterial identification technology, MALDI-TOF MS can realize the specific identification of S. aureus, and meet the rapid requirement of laboratorial identification of S. aureus in public safety and health, emergency food safety incidents and rapid customs clearance at ports.