Microbial Identification Using Surface Enhanced Laser De

细菌的鉴定传统上是通过形态特征和表型试验。一些常见微生物(例如金黄色葡萄球菌、肺炎链球菌、大肠杆菌)的鉴定可以快速(例如，不到一小时)，利用它们的特征形态和一些选定的表型试验。然而，大多数生物体的鉴定速度很慢，需要几个小时到几天的时间才能得到明确的答案。最近，基因组学的使用，如对核糖体RNA基因或看家基因进行测序，已被证明是一种有用的工具。虽然对特定基因进行测序是一种强大的鉴别工具，但目前的方法需要一天或几天才能得出结果。基因测序的一个合乎逻辑的延伸是使用基因产物进行细菌鉴定。结构基因序列的显著变化会导致蛋白质产物的变化。在过去的5年中，利用基质辅助激光解吸电离飞行时间质谱仪(MALDI-ToF MS)和表面增强激光解吸电离飞行时间质谱仪(SELDI-ToF MS)对用于鉴定的细菌蛋白质进行了初步分析。去年，我们探索了使用SELDI来鉴定选定的革兰氏阳性和革兰氏阴性细菌。今年，随着多科室临床中心购买MALDI-ToF MS系统，我们扩大了研究范围，以使用该系统。初步研究表明，大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌和粪肠球菌可以获得独特的、可重复性的图谱。MALDI系统的优点是可以分析整个细胞，降低了SELDI系统所要求的细菌裂解的可变性。MALDI系统的困难在于轮廓的复杂性。我们相信，通过最近购买数据分析软件，这个问题可以得到解决。

Identification of bacteria has traditionally been by morphologic features and phenotypic testing. Identification of some common organisms (e.g., Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli) can be rapid (e.g., less than one hour), exploiting their characteristic morphology and a few selected phenotypic tests. However, the identification of most organisms is slow, requiring hours to days for a definitive answer. More recently the use of genomics such as sequencing ribosomal RNA genes or housekeeping genes has proved to be a useful tool. Although sequencing specific genes is a powerful discriminatory tool, the current methodology requires one or more days before a result is available. A logical extension of sequencing genes is to use the gene products for bacterial identification. Significant variations in a structural gene sequence would result in variations in the protein product. In the last 5 years, preliminary work in the analysis of bacterial proteins for identification has been performed using Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-ToF MS) and Surface-Enhanced Laser Desorption/Ionization Time of Flight Mass Spectrometry (SELDI-ToF MS). Last year we explored using SELDI for identification of selected gram-positive and gram-negative bacteria. This year, with the multi-department Clinical Center purchase of the MALDI-ToF MS system, we have expanded our studies to use this system. Preliminary studies indicate that unique, reproducible profiles could be obtained for Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis. The advantage of the MALDI system is that whole cells could be analyzed, reducing the variability of bacterial lysis which was required with the SELDI system. The difficulty with the MALDI system is the complexity of the profiles. We believe this can be resolved with the recent purchase of software for data analysis.