To discern if there was a particular genotype associated with clinical enteroaggregative Escherichia coli (EAEC) strains isolated from deployed military personnel (DMP) with travelers' diarrhea (TD), we characterized a collection of EAEC from DMP deployed to Afghanistan, Djibouti, Kenya, or Honduras. Although we did not identify a specific EAEC genotype associated with TD in DMP, we found that EAEC isolated at the first clinic visit were more likely to encode the dispersin gene aap than EAEC collected at follow-up visits. A majority of the EAEC isolates were typical EAEC that adhered to HEp-2 cells, formed biofilms, and harbored genes for aggregative adherence fimbriae (AAF), AggR, and serine protease autotransporters of Enterobacteriaceae (SPATEs). A separate subset of the EAEC had aggR and genes for SPATEs but encoded a gene highly homologous to that for CS22, a fimbriae more commonly found in enterotoxigenic E. coli. None of these CS22-encoding EAEC formed biofilms in vitro or adhered to HEp-2 cells. Whole genome sequence and single nucleotide polymorphism analyses demonstrated that most of the strains were genetically diverse, but that a few were closely related. Isolation of these related strains occurred within days to more than a year apart, a finding that suggests a persistent source and genomic stability. In an ampicillin-treated mouse model we found that an agg4A+ aar- isolate formed a biofilm in the intestine and caused reduced weight gain in mice, whereas a strain that did not form an in vivo biofilm caused no morbidity. Our diverse strain collection from DMP displays the heterogeneity of EAEC strains isolated from human patients, and our mouse model of infection indicated the genotype agg4A+ aar- and/or capacity to form biofilm in vivo may correlate to disease severity.

中文翻译：

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从患有旅行者腹泻的部署军事人员 (DMP) 中分离出的肠聚集性大肠杆菌 (EAEC) 的遗传和毒力谱。

为了辨别是否存在与从患有旅行者腹泻 (TD) 的部署军事人员 (DMP) 中分离的临床肠聚集性大肠杆菌 (EAEC) 菌株相关的特定基因型，我们对部署到阿富汗、吉布提、肯尼亚的 DMP 中的 EAEC 集合进行了表征，或洪都拉斯。尽管我们没有在 DMP 中鉴定出与 TD 相关的特定 EAEC 基因型，但我们发现在第一次就诊时分离的 EAEC 比在随访时收集的 EAEC 更有可能编码分散基因 aap。大多数 EAEC 分离株是典型的 EAEC，它粘附在 HEp-2 细胞上，形成生物膜，并含有聚集粘附菌毛 (AAF)、AggR 和肠杆菌科 (SPATE) 丝氨酸蛋白酶自转运蛋白的基因。EAEC 的一个单独子集具有 aggR 和 SPATE 基因，但编码的基因与 CS22 的基因高度同源，CS22 是一种在产肠毒素大肠杆菌中更常见的菌毛。这些编码 CS22 的 EAEC 在体外均未形成生物膜或粘附于 HEp-2 细胞。全基因组序列和单核苷酸多态性分析表明，大多数菌株具有遗传多样性，但少数菌株密切相关。这些相关菌株的分离发生在几天到一年多的时间里，这一发现表明来源和基因组的稳定性。在氨苄青霉素处理的小鼠模型中，我们发现 agg4A+ aar- 分离物在肠道中形成生物膜并导致小鼠体重增加减少，而没有形成体内生物膜的菌株不会导致发病。