Tu Jian, Xue Ting, Qi Kezong, Shao Ying, Huang Boyan, Wang Xueyan, Zhou Xiuhong
Pol J Vet Sci. 2016;19(1):21-9. doi: 10.1515/pjvs-2016-0004.
Avian pathogenic Escherichia coli (APEC) is a major bacterial infectious disease that may lead to local or systemic infections in chickens with clinical manifestations. The irp2-fyuA gene cluster has been confirmed to be the main genes involved in the synthesis of HPI. The objective of this study was to determine the influence of the irp2 and fyuA genes in the high pathogenicity island (HPI) of avian pathogenic Escherichia coli (APEC) on its pathogenicity by knocking out these genes. The ΔAE17 (lacking irp2) and ΔΔAE17 (lacking irp2 and fyuA) strains of APEC were constructed. The ΔAE17 and ΔΔAE17 strains showed significantly impaired capacity to adhere onto DF-1 cells. The LD50 results indicated that the virulence of the ΔAE17 and ΔΔAE17 strains was decreased in comparison with that of the AE17 strain. We concluded that the knock-out of the core HPI genes weakened APEC adhesion onto DF-1 cells, inhibited transcription of virulence genes, and reduced pathogenicity in chicks. The effects of genetic deletion of irp2 and fyuA on APEC were more severe than those produced by deletion of irp2 only, indicating that irp2 and fyuA co-regulate APEC pathogenicity.
禽致病性大肠杆菌（APEC）是一种主要的细菌性传染病，可导致鸡出现局部或全身感染并伴有临床表现。irp2 - fyuA基因簇已被证实是参与耶尔森菌毒力岛（HPI）合成的主要基因。本研究的目的是通过敲除禽致病性大肠杆菌（APEC）高致病性岛（HPI）中的irp2和fyuA基因，来确定这些基因对其致病性的影响。构建了APEC的ΔAE17（缺失irp2）和ΔΔAE17（缺失irp2和fyuA）菌株。ΔAE17和ΔΔAE17菌株对DF - 1细胞的黏附能力显著受损。半数致死量（LD50）结果表明，与AE17菌株相比，ΔAE17和ΔΔAE17菌株的毒力降低。我们得出结论，敲除核心HPI基因会削弱APEC对DF - 1细胞的黏附，抑制毒力基因的转录，并降低雏鸡的致病性。irp2和fyuA基因缺失对APEC的影响比仅缺失irp2更为严重，表明irp2和fyuA共同调节APEC的致病性。
