Characterization of the novel factor paa involved in the early steps of the adhesion mechanism of attaching and effacing Escherichia coli
Characterization of the novel factor paa involved in the early steps of the adhesion mechanism of attaching and effacing Escherichia coli
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DOI：
10.1128/iai.71.8.4516-4525.2003
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发表时间：
2003-08-01
影响因子：
3.1
通讯作者：
Harel, J
中科院分区：
文献类型：
--
作者：
Batisson, I;Guimond, MP;Harel, J
属于血清群045的非肠源性猪大肠杆菌菌株与猪断奶后腹泻相关，并以特征性的附着和消退（A/E）模式粘附于肠上皮细胞。045猪肠道致病性E.大肠杆菌（PEPEC）菌株86-1390在猪回肠外植体模型中诱导典型的A/E损伤。利用TnphoA转座子插入诱变菌株86-1390，我们发现了一个突变体，不诱导A/E病变。在命名为paa（猪A/E相关基因）的基因中鉴定了插入。paa基因的开放阅读框为753 bp，编码27.6-kDa蛋白，与肠出血性大肠杆菌的Paa基因同源性分别为100%、51.8%和49%。coli O 157：H7菌株（EDL 933和Sakai）、空肠弯曲菌PEB 3和霍乱弧菌AcfC。染色体定位研究表明，paa基因插入到yciD和yciE基因之间，插入时间约为28.3min。coliK-12染色体。猪045菌株中存在paa和eae序列与A/E表型高度相关。然而，观察到三个eae阳性但paa阴性的PEPEC O 45菌株是A/E阴性的，这进一步证明了paa基因在O 45菌株的A/E活性中的重要性。同样，paa突变体的互补恢复了86-1390菌株的A/E活性，表明Paa参与PEPEC致病性。这些观察结果表明，Paa有助于A/E E的早期阶段。大肠杆菌毒力
Nonenterotoxigenic porcine Escherichia coli strains belonging to the serogroup 045 have been associated with postweaning diarrhea in swine and adhere to intestinal epithelial cells in a characteristic attaching and effacing (A/E) pattern. 045 porcine enteropathogenic E. coli (PEPEC) strain 86-1390 induces typical A/E lesions in a pig ileal explant model. Using TnphoA transposon insertion mutagenesis on strain 86-1390, we found a mutant that did not induce A/E lesions. The insertion was identified in a gene designated paa (porcine A/E-associated gene). Sequence analysis of paa revealed an open reading frame of 753 bp encoding a 27.6-kDa protein which displayed 100, 51.8, and 49% homology with Paa of enterohemorrhagic E. coli O157:H7 strains (EDL933 and Sakai), PEB3 of Campylobacter jejuni, and AcfC of Vibrio cholerae, respectively. Chromosomal localization studies indicated that the region containing paa was inserted between the yciD and yciE genes at about 28.3 min of the E. coli K-12 chromosome. The presence of paa and eae sequences in the porcine 045 strains is highly correlated with the A/E phenotype. However, the observation that three eae-positive but paa-negative PEPEC O45 strains were A/E negative provides further evidence for the importance of the paa gene in the A/E activity of O45 strains. As well, the complementation of the paa mutant restored the A/E activity of the 86-1390 strain, showing the involvement of Paa in PEPEC pathogenicity. These observations suggest that Paa contributes to the early stages of A/E E. coli virulence.