Yonezawa Takatoshi, Watari Tomohisa, Ashizawa Kazuho, Hanada Daisuke, Yanagiya Takako, Watanabe Naoki, Terada Takashi, Tomoda Yutaka, Fujii Satoshi
Department of Medical Laboratory and Blood Center, Asahikawa Medical University Hospital, 2-1-1-1 Midorigaokahigashi, Asahikawa, Hokkaido 078-8510, Japan.
R & D Department, Nittobo Medical Co., Ltd., 1 Shiojima, Fukuhara, Fukuyama, Koriyama, Fukushima 963-8061, Japan.
J Microbiol Methods. 2018 May;148:138-144. doi: 10.1016/j.mimet.2018.04.005. Epub 2018 Apr 12.
Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been incorporated into pathogenic bacterial identification methods and has improved their rapidity. Various methods have been reported to directly identify bacteria with MALDI-TOF MS by pretreating culture medium in blood culture bottles. Rapid BACpro® (Nittobo Medical Co., Ltd.) is a pretreatment kit for effective collection of bacteria with cationic copolymers. However, the Rapid BACpro® pretreatment kit is adapted only for MALDI Biotyper (Bruker Daltonics K.K.), and there has been a desire to expand its use to VITEK MS (VMS; bioMerieux SA). We improved the protocol and made it possible to analyze with VMS. The culture medium bacteria collection method was changed to a method with centrifugation after hemolysis using saponin; the cationic copolymer concentration was changed to 30% of the original concentration; the sequence with which reagents were added was changed; and a change was made to an ethanol/formic acid extraction method. The improved protocol enhanced the identification performance. When VMS was used, the identification rate was 100% with control samples. With clinical samples, the identification agreement rate with the cell smear method was 96.3%. The improved protocol is effective in blood culture rapid identification, being both simpler and having an improved identification performance compared with the original.
基质辅助激光解吸电离飞行时间质谱法（MALDI-TOF MS）已被纳入病原菌鉴定方法中，并提高了其检测速度。已有多种方法报道通过对血培养瓶中的培养基进行预处理，利用MALDI-TOF MS直接鉴定细菌。快速BACpro®（日东纺医疗株式会社）是一种使用阳离子共聚物有效收集细菌的预处理试剂盒。然而，快速BACpro®预处理试剂盒仅适用于MALDI Biotyper（布鲁克道尔顿公司），人们一直希望将其应用扩展到VITEK MS（VMS；生物梅里埃公司）。我们改进了方案，使其能够用VMS进行分析。将培养基细菌收集方法改为使用皂苷溶血后离心的方法；将阳离子共聚物浓度改为原来浓度的30%；改变了试剂添加顺序；并改为乙醇/甲酸提取法。改进后的方案提高了鉴定性能。使用VMS时，对照样品的鉴定率为100%。对于临床样品，与细胞涂片法的鉴定符合率为96.3%。改进后的方案在血培养快速鉴定中有效，与原方案相比既更简单又具有更好的鉴定性能。
