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Abstract：
Matrix-assisted laser desorption ionization time-of-flight mass spectrometry has been widely used as an emerging technology for the rapid identification of microorganisms. Cronobacter sakazakii (C. sakazakii) is a food-borne pathogen of particular importance to the powdered infant formula (PIF) processing environment due to its high lethality in infants. However, the traditional solid spotting detection method of pretreating samples for MALDI-TOF MS leads only to qualitative detection of C. sakazakii. We developed a new, low-cost, robust liquid spotting pretreatment method and used a response surface methodology to optimize its parameters. The applicability, accuracy, and quantitative potential were measured for different types of samples. The optimal parameters of this method were as follows: a volume of 70% formic acid of 25 μL, treatment with ultrasound at 350 W for 3 min, and a volume of acetonitrile added of 75 μL. These conditions led to the highest identification score for C. sakazakii (1926.42 ± 48.497). This method was found to detect bacteria accurately and reproducibly. When 70 strains of C. sakazakii isolates were analyzed with this method, the identification accuracy was 100%. The detection limit of C. sakazakii in environmental and PIF samples was 4.1 × 101 cfu/mL and 2.72 × 103 cfu/mL, respectively.
摘要：
基质辅助激光解吸电离飞行时间质谱技术作为一种新兴的微生物快速鉴定技术得到了广泛的应用。SakazakiiCronobacter(C.Sakazakii）是一种食源性病原体，由于其在婴儿中的高致死率，对婴儿配方奶粉（PIF）加工环境特别重要。然而,传统的对MALDI-TOFMS样品进行预处理的固体点样检测方法仅导致对Sakazakii的定性检测。我们开发了一种新的,低成本,稳健的液体斑点预处理方法，并使用响应面法优化其参数。适用性,准确度,并对不同类型的样品进行了定量电位测量。该方法的最佳参数如下：70％甲酸的体积为25μL，用350W超声治疗3分钟，和加入75μL体积的乙腈。这些条件导致了对Sakazakii的最高鉴定得分(1926.42±48.497)。发现该方法可以准确且可重复地检测细菌。用这种方法分析了70株崎氏杆菌分离株，识别准确率为100%。Sakazakii在环境和PIF样品中的检出限为4.1×101cfu/mL和2.72×103cfu/mL，分别。
