Bania Jacek, Dabrowska Anna, Bystron Jarosław, Korzekwa Kamila, Chrzanowska Jozefa, Molenda Jerzy
Department of Food Hygiene and Consumer Protection, Faculty of Veterinary Medicine, Agricultural University of Wroclaw, Norwida 31, 50-375 Wroclaw, Poland.
Int J Food Microbiol. 2006 Apr 15;108(1):36-41. doi: 10.1016/j.ijfoodmicro.2005.10.013. Epub 2005 Dec 27.
Extensive analysis of the Staphylococcus aureus genome has allowed the identification of new genes encoding enterotoxin-like superantigens (SEls). Some of these are thought to be involved in staphylococcal food poisoning, while others do not elicit any emetic effect. The potential impact of these members of the enterotoxin-like family on the human organism seems to rely mainly on their superantigenic activity. In this paper the distribution of the genes coding for enterotoxin-like superantigens in S. aureus isolated from food was studied. Fifty isolates of S. aureus were examined and 27 were shown to be enterotoxigenic. Only 9 of the 27 strains carried genes encoding enterotoxins SEA-SEE. In 18 SEA-SEE-negative strains the presence of newly described enterotoxin genes was detected. All SEA-SEE-positive strains simultaneously carried genes of new SEls. We show that the gene encoding SElH (staphylococcal enterotoxin-like enterotoxin H) was the most frequently detected (n=14), while genes encoding SElI together with SElG accompanied by the other genes of the egc locus were detected in three strains. We also detected the presence of three less investigated genes: sep, sel, and sek. These genes were present in eight, two, and one isolate, respectively. In one strain, sep was accompanied by genes of other SEls, while in the remaining seven it was the only enterotoxin-like gene detected. The high prevalence of newly discovered enterotoxin genes, including the genes encoding emetic toxins, was demonstrated in food-derived strains. This supports the need for additional work on its role in food poisoning and, alternatively, to monitor its presence in S. aureus isolated from food. Our results suggest that yet unknown genetic elements encoding enterotoxin genes may exist.
对金黄色葡萄球菌基因组的广泛分析使得能够鉴定出编码类肠毒素超抗原（SEls）的新基因。其中一些被认为与葡萄球菌食物中毒有关，而其他一些则不会引起任何催吐作用。类肠毒素家族的这些成员对人体的潜在影响似乎主要依赖于它们的超抗原活性。本文研究了从食物中分离的金黄色葡萄球菌中编码类肠毒素超抗原的基因分布。检测了50株金黄色葡萄球菌，其中27株被证明产肠毒素。27株菌株中只有9株携带编码肠毒素SEA - SEE的基因。在18株SEA - SEE阴性菌株中检测到新描述的肠毒素基因的存在。所有SEA - SEE阳性菌株同时携带新SEls的基因。我们发现编码SElH（类葡萄球菌肠毒素H）的基因是最常检测到的（n = 14），而编码SElI以及SElG并伴有egc位点其他基因的基因在3株菌株中被检测到。我们还检测到3个研究较少的基因：sep、sel和sek的存在。这些基因分别存在于8株、2株和1株分离物中。在1株菌株中，sep与其他SEls的基因同时存在，而在其余7株中它是唯一检测到的类肠毒素基因。在食物来源的菌株中证实了新发现的肠毒素基因，包括编码催吐毒素的基因的高流行率。这支持了有必要进一步研究其在食物中毒中的作用，或者监测从食物中分离的金黄色葡萄球菌中其存在情况。我们的结果表明可能存在尚未知晓编码肠毒素基因的遗传元件。
