Department of Analytical Chemistry, Nutrition and Food Science, School of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain.
Electrophoresis. 2011 Nov;32(21):2951-65. doi: 10.1002/elps.201100217. Epub 2011 Oct 18.
The rapid identification of food pathogenic and spoilage bacteria is important to ensure food quality and safety. Seafood contaminated with pathogenic bacteria is one of the major causes of food intoxications, and the rapid spoilage of seafood products results in high economic losses. In this study, a collection of the main seafood pathogenic and spoilage Gram-positive bacteria was compiled, including Bacillus spp., Listeria spp., Clostridium spp., Staphylococcus spp. and Carnobacterium spp. The strains, belonging to 20 different species, were obtained from the culture collections and studied by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). A reference library was created, including the spectral fingerprints of 32 reference strains and the extracted peak lists with 10-30 peak masses. Genus-specific as well as species-specific peak masses were assigned and could serve as biomarkers for the rapid bacterial identification. Furthermore, the peak mass lists were clustered with the web-application SPECLUST to show the phyloproteomic relationships among the studied strains. Afterwards, the method was successfully applied to identify six strains isolated from seafood by comparison with the reference library. Additionally, phylogenetic analysis based on the 16S rRNA gene was carried out and contrasted with the proteomic approach. This is the first time MALDI-TOF MS fingerprinting is applied to Gram-positive bacterial identification in seafood, being a fast and accurate technique to ensure seafood quality and safety.
快速鉴定食源性致病菌和腐败菌对于确保食品质量和安全至关重要。受致病菌污染的海鲜是食物中毒的主要原因之一，而海鲜产品的快速变质会导致巨大的经济损失。本研究中，我们汇集了主要的食源性致病菌和腐败菌，包括芽孢杆菌属、李斯特菌属、梭菌属、葡萄球菌属和食酸菌属。这些菌株来自于不同的菌种库，属于 20 个不同的物种，通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）进行了研究。我们创建了一个参考库，其中包含 32 个参考菌株的光谱指纹图谱和 10-30 个峰质量的提取峰列表。分配了属特异性和种特异性的峰质量，可作为快速细菌鉴定的生物标志物。此外，我们使用网络应用程序 SPECLUST 对峰质量列表进行聚类，以显示研究菌株之间的 phyloproteomic 关系。然后，通过与参考库进行比较，成功应用该方法鉴定了从海鲜中分离出的 6 株菌株。此外，还进行了基于 16S rRNA 基因的系统发育分析，并与蛋白质组学方法进行了对比。这是首次将 MALDI-TOF MS 指纹图谱应用于海鲜中革兰氏阳性菌的鉴定，是一种快速、准确的保证海鲜质量和安全的技术。
