In this study, 53 Staphylococcus (S.) aureus strains were typed by 16S-23S rDNA intergenic spacer region (ISR) typing and staphylococcal enterotoxin gene (SEg) typing for all the staphylococcal enterotoxin (se) and staphylococcal enterotoxin-like toxin (sel) genes known to date, revealing a higher discriminatory power than that of multi locus sequence typing. Six strains, one of each ISR- and SEg-type, were genome sequenced and the ability to produce some classical and new SEs when growing in milk was investigated. The manual analysis of the six genomes allowed us to confirm, correct and expand the results of common available genomic data pipelines such as VirulenceFinder. Moreover, it enabled us to (i) investigate the actual location of se and sel genes, even for genes such as selY, whose location (in the core genome) was so far unknown, (ii) find novel allelic variants of se and sel genes and pseudogenes, (iii) correctly annotate se and sel genes and pseudogenes, and (iv) discover a novel type of enterotoxin gene cluster (egc), i.e. the egc type 5 in strains 356P and 364P, while S. argenteus MSHR1132 harbored the egc type 6. Four of the six S. aureus strains produced sufficient amounts of SEA, SEC, SED and SEH in milk to cause staphylococcal food poisoning (SFP), with S. aureus 372 P being the highest producer of SED in milk found to date, producing as much as ca. 47,300 ng/mL and 49,200 ng/mL of SED, after 24 and 48 h of incubation in milk at 37 °C, respectively. S. aureus 372 P released a low amount of SER in milk, most likely because the seR gene was present as a pseudogene, putatively encoding only 51 amino acids. These findings confirm that not only the classical SEs, but also the new ones can represent a potential hazard for the consumers' health if produced in foods in sufficient amounts. Therefore, the detection of SEs in foods, especially if involved in SFP cases, should focus not only on classical, but also on all the new SEs and SEls known to date. Where reference methods are unavailable, the presence of the relevant genes, by using the conventional and real time PCR protocols we exhaustively provided herein, and their nucleotide sequences, should be investigated.

中文翻译：

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对从生乳中分离出的金黄色葡萄球菌的产肠毒素潜力和基因组背景的新颖见解。

在这项研究中，通过所有葡萄球菌肠毒素（se）和类葡萄球菌肠毒素（sel）的16S-23S rDNA基因间隔区（ISR）分型和葡萄球菌肠毒素基因（SEg）分型的53株金黄色葡萄球菌菌株。 ）迄今已知的基因，比多基因座序列分型具有更高的鉴别力。对六种菌株（分别是ISR型和SEg型之一）进行了基因组测序，并研究了在牛奶中生长时产生一些经典SE和新SE的能力。对六个基因组的手动分析使我们能够确认，纠正和扩展常见的可用基因组数据管道（例如VirulenceFinder）的结果。而且，它使我们能够（i）研究se和sel基因的实际位置，甚至对于selY这样的基因（在核心基因组中的位置，目前尚不清楚），（ii）找到se和sel基因和假基因的新等位基因变体，（iii）正确注释se和sel基因和假基因，并且（iv）发现新型肠毒素基因簇（egc），即菌株中的egc 5型356P和364P，而阿根廷链球菌MSHR1132则具有egc类型6。六个金黄色葡萄球菌菌株中的四个在牛奶中产生足够量的SEA，SEC，SED和SEH，导致金黄色葡萄球菌食物中毒（SFP）。 P是迄今为止发现的牛奶中SED的最高生产者，产量约为。在37°C的牛奶中分别孵育24和48小时后，SED分别为47,300 ng / mL和49,200 ng / mL。金黄色葡萄球菌372 P在牛奶中释放少量SER，最可能是因为seR基因作为假基因存在，假定仅编码51个氨基酸。这些发现证实，不仅经典的SE，但是如果以足够的量生产新食品，可能会对消费者的健康构成潜在危害。因此，食品中SE的检测，尤其是涉及SFP案例的SE的检测，不仅应着眼于经典，而且应关注所有已知的新的SE和SE1。在没有参考方法的情况下，应使用我们在此详尽提供的常规和实时PCR方案，研究相关基因的存在及其核苷酸序列。