基質輔助雷射脫附游離飛行質譜儀(MALDI-TOF MS)鑑定食品病原菌及大腸桿菌群的效能

The Efficacy of MALDI-TOF MS for the Identification of the Members of Food Pathogens and Indicator Organisms

賴淑婷(Shu-Ting Lai) ； 李彥廷(Yen-Ting Li) ； 陳羿樺(I-Hua Cheng) ； 蔡文城(Wen-cherng Tsai)

《檢驗及品保雜誌》 6卷2期 (2017/05) Pp. 83-91

https://doi.org/10.6573/JTQA.201705_6(2).03

摘要

近年來，基質輔助雷射脫附游離飛行質譜儀(Matrix-assisted laser desorption ionization-time of flight mass spectrometry, MALDI-TOF MS)漸被用於臨床微生物檢驗室或工業廠房品管室分離菌的鑑定，由於此系統的圖譜資料庫大多以臨床分離菌為主，是否能用於食品衛生指標菌或病原菌的鑑定有必要加以評估。本研究利用台美檢驗科技有限公司2014 年至2016 年所保存的475 株食品檢體分離株及46 株購自財團法人食品工業研究所食品病原菌標準菌株（共521 株）做為MALDI-TOF MS 鑑定的目標菌株，結果指出本系統(i)對所有測試菌鑑定到菌屬層次的正確率為91.6%(477/521)，而鑑定至菌種層次為84.8%(442/521)。(ii)鑑定測試菌中的革蘭氏陽性球菌、革蘭氏陽性桿菌與革蘭氏陰性桿菌至菌屬層次的正確性分別為98.4%、92.8%及90.2%，而菌種層次則為91.0%、82.6%及85.1%。(iii)鑑定需要血清型確認的沙門氏菌(Salmonella spp.)、志賀氏菌(Shigella spp.)與Escherchia coli (O157:H7)至菌屬及菌種層次的正確性分別為57.9%、0%與50%以及47.4%、0%與50%。(iv)鑑定Enterobacter aerogenes、Aeromonas hydrophila、Aeromonas schubertii 與Pseudomonas fluorescens 至菌種層次的正確性較低。另外，本研究亦探討大腸桿菌群陽性檢體所包括菌種類別及個別菌種所占的比例，結果發現以Enterobacter cloacae佔最多(81.3%，26/32)，其餘為Klebsiella pneumoniae、Klebsiella oxytoca 、Escherichia coli、Serratia marcescens 及Citrobacter freundii。上述的發現指出MALDI-TOF MS 對食品衛生指標菌及病原菌的鑑定有良好的效能，食品廠品管室在經費許可下可引進做為傳統鑑定方法的參考。

關鍵字

食品病原菌 ； 大腸桿菌群 ； MALDI-TOF MS

並列摘要

Recently, Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been implemented in clinical microbiology laboratory or industrial quality control laboratory for microbial identification. Because most of the data bases were established based on the clinical microbial isolates, therefore, it became necessary to evaluate whether it could be applied to the identification of food sanitary index organisms (indicators organisms) or food-mediated pathogens. This studies used 475 stock culture isolated between 2014 and 2016 in the Super laboratory, Ltd., and 46 strains purchased from the Food Industry Research and Development Institute (totally 521 strains) as tested isolates by Brucker Biotyper, one of the MALDI-TOF MS systems. Results indicated that (i) the correct identification rate to genus level is 91.6%(477/521), and to species level 84.8%(442/521). (ii) Among all tested isolates, the correct identification rates to genus level for Gram-positive cocci, Gram-positive bacbacilli and Gram-negative bacilli are 98.4%, 92.8% and 90.2%, individually, and to species level 91.0%, 82.6% and 85.1%, individually. (iii) correct identification to genus and species level for Salmonella spp., Shigella spp. and Escherchia coli O157:H7 which required to be confirmed by serological tests are 57.9%, 0%, 50% and 47.4%, 0%, 50%. and (iv) correct identification to species level are low for Enterobacter aerogenes, Aeromonas hydrophila, Aeromonas schubertii and Pseudomonas fluorescens. Additionally, this study are also tried to identify the members of coliforms, one of the sanitary indicator microorganisms, on positive food specimens and results indicated that the most frequently encountered organism among coliformis is Enterobacter cloacae (81.3%, 26/32)，the remaining are Klebsiella pneumoniae, Klebsiella oxytoca 、Escherichia coli，Serratia marcescens and Citrobacter freundii. Based on the above findings, we concluded that MALDI-TOF MS is a good tool for the identification of indicator microorganisms and pathogens isolated from food. Under permission of financial support from administrator, the instrument can be implemented to the quality control laboratory for rapid microbial identification which will use as a reference for the conventional method.

並列關鍵字

MALDI-TOFMS ； food sanitory indicators organisms ； foog-mediated pathogens