Graduate School of Human Life Science, Osaka City University.
Department of Surgery & Theriogenology, Sher-e-Bangla Agricultural University.
Jpn J Infect Dis. 2020 Jan 23;73(1):76-82. doi: 10.7883/yoken.JJID.2019.016. Epub 2019 Aug 30.
Using multiplex real-time PCR, 960 fecal samples collected from poultry, cattle, and patients with diarrhea in Bangladesh were screened for diarrheagenic Escherichia coli (DEC). The invasion-related gene virB showed the highest prevalence in human patients (41%) and was shown to be positively correlated first with afaB with regards to diffuse adhesion and second with aggR with regards to aggregative adhesion. These three genes were specific to human patients. In contrast, the Shiga toxin genes stx1 (57%) and stx2 (40%) were prevalent in cattle samples. The eae gene, which is associated with attaching and effacing lesion formation, and the elt and est genes, which are associated with enterotoxins, were detected from all three sample sources. Heat map construction and hierarchical clustering assigned the samples into five different clusters, with the patient samples positive for virB and afaB being placed together in one cluster. Although the detection of virulence genes cannot be a direct indication of the distribution of diarrheagenic organisms, their detection suggests that Shigella spp. or enteroinvasive E. coli are the most prevalent diarrheagenic bacteria in Bangladesh and that diffusely adherent E. coli is concomitantly present with these bacteria. eae-possessing organisms in patients may come from cattle and poultry sources. The small number of stx-positive patients could be explained by the small number of animal samples that were positive for both eae and stx.
使用多重实时 PCR，对来自孟加拉国家禽、牛和腹泻患者的 960 份粪便样本进行了腹泻性大肠杆菌（DEC）的筛查。侵袭相关基因 virB 在人类患者（41%）中的检出率最高，且与弥散黏附相关的 afaB 呈正相关，与聚集黏附相关的 aggR 呈正相关。这三个基因是人类患者特有的。相比之下，牛样本地流行志贺毒素基因 stx1（57%）和 stx2（40%）。与附着和破坏病变形成相关的 eae 基因，以及与肠毒素相关的 elt 和 est 基因，在这三种样本来源中均有检出。热图构建和层次聚类将样本分为五个不同的簇，virB 和 afaB 阳性的患者样本聚为一簇。虽然毒力基因的检测不能直接指示腹泻病原体的分布，但它们的检测表明，志贺菌属或侵袭性大肠杆菌是孟加拉国最常见的腹泻性细菌，而弥漫黏附性大肠杆菌与这些细菌同时存在。患者中携带 eae 的病原体可能来自牛和家禽来源。stx 阳性患者数量较少，可能是因为既携带 eae 又携带 stx 的动物样本数量较少。
