Morandi Stefano, Brasca Milena, Andrighetto Cristian, Lombardi Angiolella, Lodi Roberta
CNR Istituto di Scienze delle Produzioni Alimentari (ISPA), Sez. Milano, Via Celoria 2, 20133 Milan, Italy.
Int J Microbiol. 2009;2009:501362. doi: 10.1155/2009/501362. Epub 2010 Jan 27.
Staphylococcus aureus is a known major cause of foodborne illnesses, and milk and dairy products are often contaminated by enterotoxigenic strains of this bacterium. In the present study, 122 S. aureus isolates collected from different dairy products were characterised by phenotypic properties, by the distribution of genes encoding staphylococcal enterotoxins (sea, sec, sed, seg, seh, sei, sej, and sel) and by randomly amplified polymorphic DNA PCR (RAPD-PCR). Moreover, strain resistance to vancomycin and methicillin (oxacillin) was studied. The differences in the RAPD-PCR profiles obtained with the primers M13 and AP4 revealed the presence of a great genetic heterogeneity among the different S. aureus strains. Using the primer AP4 and M13, eight groups were distinguished by RAPD-PCR cluster analysis, although, except in few cases, it was not possible to correlate the isolates of different animal species (cow or ovine) with the presence of se genes. None of the isolates showed resistance to vancomycin or methicillin.
金黄色葡萄球菌是食源性疾病的一个已知主要病因，牛奶和乳制品常常被该细菌的产肠毒素菌株污染。在本研究中，从不同乳制品中收集的122株金黄色葡萄球菌分离株通过表型特性、编码葡萄球菌肠毒素的基因（sea、sec、sed、seg、seh、sei、sej和sel）的分布以及随机扩增多态性DNA聚合酶链反应（RAPD-PCR）进行了表征。此外，还研究了菌株对万古霉素和甲氧西林（苯唑西林）的耐药性。用引物M13和AP4获得的RAPD-PCR图谱差异揭示了不同金黄色葡萄球菌菌株之间存在很大的遗传异质性。使用引物AP4和M13，通过RAPD-PCR聚类分析区分出八组，不过，除了少数情况外，无法将不同动物物种（牛或羊）的分离株与se基因的存在相关联。没有分离株显示出对万古霉素或甲氧西林耐药。
