克罗诺杆菌属食品分离株种水平鉴定方法比较研究

目的研究食品中分离克罗诺杆菌属种的鉴定方法,旨在建立稳定、可靠的种的鉴定方法。方法本研究选择三种鉴定方法,包括生化鉴定(VITEK 2 Compact)法、基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)、全基因组测序,通过比较分析三种方法对19株克罗诺杆菌属的鉴定结果,阐述三种鉴定方法的优缺点及其适用性。结果本研究中19株克罗诺杆菌属的鉴定结果显示,VITEK 2 Compact对阪崎克罗诺杆菌和丙二酸盐克罗诺杆菌的鉴定准确率只有67%和66%,而MALDI-TOF MS和全基因组测序的鉴定结果一致,因此可以判定MALDI-TOF MS能够快速、准确、高通量对克罗诺杆菌属进行种的鉴定。但是MALDI-TOF MS受限于数据库,不能鉴定到亚种的水平。结论本研究结果提示VITEK 2 Compact法不适用于克罗诺杆菌属种的鉴定;全基因组测序鉴定结果准确可靠;MALDI-TOF MS可以实现快速、高通量、准确的鉴定,仍需要进一步研究克罗诺杆菌属3个亚种的蛋白指纹图谱特点,丰富蛋白指纹图谱数据库,使其能够准确鉴定克罗诺杆菌属的7个种和3个亚种。

Study on species identification of Cronobacter spp. in foods

Objective To compare the species identification method of Cronobacter spp. in food, in order to establish rapid, high throughout identification method. Methods A total of 19 Cronobacter spp. in foods were identified with three method including biochemical method using VITEK 2.0 Compact, matrix assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS)and whole-genome sequencing (WGS). The advantages and disadvantages of the three identification method were analyzed. Results The result indicated that the accuracy of VITEK identification for C.sakazakii and C.malonaticus was 67% and 66% respectively. However, WGS and MALDI-TOF MS obtained the same result for 19 Cronobacter spp.. Three subspecies could not be identified by MALDI-TOF MS due to the limited database. Conclusion Biochemical method could not be used for species identification of Cronobacter spp. MALDI-TOF MS was rapid, high throughout and accurate, but still need to expand the fingerprint database for more Cronobacter spp. isolates.