University of Texas School of Public Health, USA.
University of Texas School of Public Health, USA.
Microb Pathog. 2019 Mar;128:97-99. doi: 10.1016/j.micpath.2018.12.030. Epub 2018 Dec 21.
Enteroaggregative E. coli strains are important causes of diarrhea worldwide and are the second most important bacterial cause of travelers' diarrhea (TD). Pathogenicity of EAEC is not completely understood. We investigated the occurrence of putative virulence related genes (VRG), aatA, aggR and aaiC, in a nested case-control study of a cohort of US travelers >18 years of age, visited either Guatemala or Mexico. Fecal samples were collected between 2008 and 2012 from patients with TD from whom a HEp-2 cell adherent EAEC strain was identified (Cases) and from healthy subjects in the same locale without diarrhea from whom enteric pathogens were not isolated (Controls). Thirty-one subjects with acquired TD at destination was compared with 32 healthy controls. aaiC was the most expressed virulence related gene in 21 (67.7%) cases vs. 2 (6.3%) controls, (P < 0.000). aggR was found in 18 (58.1%) cases vs. 1 (3.1%) control, (P < 0.000). aatA in 9 (29.0%) cases vs. 1 (3.1%) control (P < 0.006). With genes combined, aaiC+aggR were seen together in 18 (58.1%) cases vs. 1 (3.1%) control (P < 0.000); aaiC+aatA were identified in 9 (29.0%) cases vs. 1 (3.1%) control (P < 0.006); aggR+aatA were present in 9 (29.0%) cases vs. 1 (3.1%) control, (P < 0.006). All three putative genes, aaiC+aggR+aatA were found in 9 (29.0%) cases vs. 1 (3.1%) control, (P < 0.006). The PCR products showed that aaiC, aggR, and aatA occurred in higher frequency and were more commonly associated with EAEC in cases of TD acquired in the two countries of study, as compared to controls. aaiC was found in all cases from Guatemala. Further research is needed to study geographic and host factors in EAEC-causing travelers' diarrhea.
肠聚集性大肠杆菌菌株是世界范围内腹泻的重要病因，也是旅行者腹泻（TD）的第二大重要细菌病因。EAEC 的致病性尚未完全了解。我们在一项针对美国旅行者的嵌套病例对照研究中调查了潜在的毒力相关基因（VRG）、aatA、aggR 和 aaiC 的发生情况，这些旅行者年龄均大于 18 岁，分别前往危地马拉或墨西哥。2008 年至 2012 年间，从在目的地获得获得性 TD 的 31 名患者中收集粪便样本，这些患者中分离出了 HEp-2 细胞粘附性 EAEC 菌株（病例），并从同一地点无腹泻的健康受试者中收集了未分离出肠道病原体的粪便样本（对照）。将 31 名获得性 TD 患者与 32 名健康对照进行比较。21 例（67.7%）病例中 aaiC 为最表达的毒力相关基因，而 2 例（6.3%）对照中为 aaiC，（P < 0.000）。18 例（58.1%）病例中发现 aggR，而 1 例（3.1%）对照中为 aggR，（P < 0.000）。9 例（29.0%）病例中有 aatA，而 1 例（3.1%）对照中有 aatA，（P < 0.006）。将基因结合起来，18 例（58.1%）病例中有 aaiC+aggR，而 1 例（3.1%）对照中有 aaiC+aggR，（P < 0.000）；9 例（29.0%）病例中有 aaiC+aatA，而 1 例（3.1%）对照中有 aaiC+aatA，（P < 0.006）；9 例（29.0%）病例中有 aggR+aatA，而 1 例（3.1%）对照中有 aggR+aatA，（P < 0.006）。9 例（29.0%）病例中有所有三个假定基因 aaiC+aggR+aatA，而 1 例（3.1%）对照中有所有三个假定基因 aaiC+aggR+aatA，（P < 0.006）。与对照组相比，在来自两国的 TD 病例中，PCR 产物显示 aaiC、aggR 和 aatA 发生频率更高，并且更常与 EAEC 相关。危地马拉的所有病例均发现 aaiC。需要进一步研究地理和宿主因素在 EAEC 引起的旅行者腹泻中的作用。
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