Kobayashi Kazuhiro, Seto Kazuko, Yatsuyanagi Jyun, Saito Shioko, Terao Michinori, Kaneko Michiharu, Serikawa Toshihiko, Kuramoto Sanae, Fujisawa Tomohiko, Suzuki Rieko, Yamazaki Mitsugu, Hayashi Ken-ichi, Matsune Wataru, Yasuoka Tomihisa, Horikawa Kazumi, Murakami Koichi, Kawano Kimiko, Yamada Toru, Ito Kenitiro
Osaka Prefectural Institute of Public Health.
Kansenshogaku Zasshi. 2002 Nov;76(11):911-20. doi: 10.11150/kansenshogakuzasshi1970.76.911.
Diarrheagenic Escherichia coli are differentiated from non-pathogenic members with enterotoxin production, enteroinvasiveness and serotyping. However, the serotypic members are rarely sufficient to reliably identify a strain as diarrheagenic on E. coli. Recently, there are many definite articles which the adhesive E. coli strain against intestinal epithelial cells is enterovirulent. In this study, 1,748 E. coli isolates of diarrheagenic and non-diarrheagenic categories which belonged to EHEC, ETEC, EIEC EPEC and non-EPEC were examinated by PCR method for the presence of eaeA, aggR and bfpA regarding adherence factor genes, and astA of EAST1. The strains examined were recognized to variable carrying geno-patterns, and a large number of EHEC, EPEC and non-EPEC had carried either eaeA or aggR genes. In EHEC isolates, a carrying pattern with the most high frequency was only eaeA, and this type was recognized in the isolates of serotype O157, O26 and O111. EPEC and non-EPEC isolates were recognized eaeA or aggR which harboring with astA or not. Of 508 EPEC isolates from human, a total of 137 isolates (27.0%) carried aggR, and a total of 74 isolates (14.6%) had eaeA, while of the 91 isolates from non-human were recognized aggR and eaeA with 2.2% (2 isolates) and 12.1% (11 isolates), respectively. Also, of 266 non-EPEC isolates from human, a total of 16 isolates (6.0%) carried aggR, and a total of 58 isolates (21.8%) had eaeA. On the other hand, 22 (7.0%) of 316 isolates examined from non-human had eaeA, however no isolate had aggR. Thirteen isolates of EIEC and 218 ETEC isolates were screened, and only 6 ETEC isolates had either eaeA or aggR. The astA gene was recognized in the isolates of all categories, and ETEC strains had more frequently. The bfpA gene was recognized with more frequently in a serotype O157: H45, which is obtained from human with diarrhea, however, this strain was not recognized a member of the EPEC serotype. There is no diagnostic system for the strain of E. coli that cause diarrheal diseases, therefore more laboratories are unable to identify them. The authors had confirmed which PCR technique is a useful simple and rapid method for the detection of adherence factor genes on E. coli strains. From the these results, we showed a differentiation method using PCR technique which have relation with adherence factor, enterotoxin-production and invasiveness, and we firmly believe that application of the procedure is a reasonable and useful method for the identification of diarrheagenic E. coli.
致泻性大肠杆菌可通过产生肠毒素、具有肠侵袭性和血清分型与非致病性成员区分开来。然而，血清型成员很少足以可靠地将一株大肠杆菌鉴定为致泻性菌株。最近，有许多明确的文章指出，黏附于肠道上皮细胞的大肠杆菌菌株具有肠毒性。在本研究中，采用聚合酶链反应（PCR）方法，对属于肠出血性大肠杆菌（EHEC）、肠产毒性大肠杆菌（ETEC）、肠侵袭性大肠杆菌（EIEC）、肠致病性大肠杆菌（EPEC）和非EPEC的1748株致泻性和非致泻性大肠杆菌分离株进行检测，以确定是否存在与黏附因子基因相关的eaeA、aggR和bfpA，以及EAST1的astA。所检测的菌株具有不同的基因模式，大量的EHEC、EPEC和非EPEC携带eaeA或aggR基因。在EHEC分离株中，最常见的携带模式仅为eaeA，这种类型在血清型O157、O26和O111的分离株中被识别。EPEC和非EPEC分离株被识别出携带或不携带astA的eaeA或aggR。在508株来自人类的EPEC分离株中，共有137株（27.0%）携带aggR，共有74株（14.6%）携带eaeA，而在91株来自非人类的分离株中，分别有2.2%（2株）和12.1%（11株）被识别出携带aggR和eaeA。此外，在266株来自人类的非EPEC分离株中，共有16株（6.0%）携带aggR，共有58株（21.8%）携带eaeA。另一方面，在316株来自非人类的检测分离株中，有22株（7.0%）携带eaeA，但没有分离株携带aggR。对13株EIEC分离株和218株ETEC分离株进行了筛选，只有6株ETEC分离株携带eaeA或aggR。astA基因在所有类别分离株中均有发现，且在ETEC菌株中更常见。bfpA基因在一株从腹泻患者分离出的血清型O157:H45中更常见，但该菌株不被认为是EPEC血清型的成员。目前尚无针对引起腹泻疾病的大肠杆菌菌株的诊断系统，因此更多实验室无法对其进行鉴定。作者证实，PCR技术是一种用于检测大肠杆菌菌株黏附因子基因的有用、简单且快速的方法。基于这些结果，我们展示了一种利用PCR技术的区分方法，该方法与黏附因子、肠毒素产生和侵袭性相关，并且我们坚信该方法的应用是鉴定致泻性大肠杆菌的一种合理且有用的方法。
