Sato'o Yusuke, Omoe Katsuhiko, Aikawa Yasuko, Kano Mayuko, Ono Hisaya K, Hu Dong-Liang, Nakane Akio, Sugai Motoyuki
Department of Bacteriology, Hiroshima University Graduate School of Biomedical & Health Sciences, Hiroshima-shi, Hiroshima 734-8551, Japan.
Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka, Iwate 020-8550, Japan.
J Vet Med Sci. 2021 Jul 13;83(7):1120-1127. doi: 10.1292/jvms.20-0662. Epub 2021 May 26.
Staphylococcus aureus produces staphylococcal enterotoxins (SEs) and causes food poisoning. It is known that almost all SE-encoding genes are present on various types of mobile genetic elements and can mobilize among S. aureus populations. Further, plasmids comprise one of SE gene carriers. Previously, we reported novel SEs, SES and SET, harbored by the plasmid pF5 from Fukuoka5. In the present study, we analyzed the distribution of these SEs in various S. aureus isolates in Japan. We used 526 S. aureus strains and found 311 strains positive for at least one SE/SE-like toxin gene, but only two strains (Fukuoka5 and Hiroshima3) were positive for ses and set among the specimens. We analyzed two plasmids (pF5 and pH3) from these strains and found that they were different. Whereas these plasmids partially shared similar sequences involved in the ser/selj/set/ses gene cluster, other sequences were different. A comparison of these plasmids with those deposited in the NCBI database revealed that only one plasmid had the ser/selj/set/ses cluster with a stop mutation in set similar to that in pH3. In addition, the chromosomes of Fukuoka5 and Hiroshima3, positive for ses and set, were classified into different genotypes. Despite the low rate of gene positivity for these SEs, it is suggested that there is diversity in plasmids and strains carrying these two SEs. Consequently, regarding the entire feature of SE prevalence, we improved the multiplex PCR detection method for the SE superfamily to obtain further insight.
金黄色葡萄球菌产生葡萄球菌肠毒素（SEs）并导致食物中毒。已知几乎所有编码SE的基因都存在于各种类型的移动遗传元件上，并且可以在金黄色葡萄球菌群体中移动。此外，质粒是SE基因载体之一。此前，我们报道了来自福冈5号菌株的质粒pF5携带的新型SEs，即SES和SET。在本研究中，我们分析了这些SEs在日本各种金黄色葡萄球菌分离株中的分布情况。我们使用了526株金黄色葡萄球菌菌株，发现311株至少对一种SE/SE样毒素基因呈阳性，但在这些标本中只有两株（福冈5号和广岛3号）对ses和set呈阳性。我们分析了来自这些菌株的两个质粒（pF5和pH3），发现它们不同。虽然这些质粒部分共享了ser/selj/set/ses基因簇中相似的序列，但其他序列不同。将这些质粒与NCBI数据库中保存的质粒进行比较发现，只有一个质粒具有与pH3中相似的在set处有终止突变的ser/selj/set/ses簇。此外，对ses和set呈阳性的福冈5号和广岛3号菌株的染色体被分类为不同的基因型。尽管这些SEs的基因阳性率较低，但表明携带这两种SEs的质粒和菌株存在多样性。因此，关于SE流行的整体特征，我们改进了SE超家族的多重PCR检测方法以获得更深入的了解。
