High Pathogenicity Island (HPI) Main Structural Genes and their Bioinformatics Analysis in Clinically Isolated E. coli from Saba Pigs
High Pathogenicity Island (HPI) Main Structural Genes and their Bioinformatics Analysis in Clinically Isolated E. coli from Saba Pigs
Chunlan Shan1, Chaoying Liu1, Qin Lu1, Guowen Fu2, Syed Aftab Hussain Shah3, Rana Waseem Akhtar4, Ru Zhao2, Libo Gao2, Chang Liu2, Shushu Miao2, Hongdan Wang2 and Hong Gao2*
ABSTRACT
High pathogenicity island (HPI), a critical genomic element of pathogenic Yersiniabactin (Ybt) carries out synthesis, regulation, transportation as well as virulence. As a virulent determinant for the E. coli, the role of HPI in Saba pig was explored to provide some perspective about disease association. This is the first study in which 44 E. coli superior serotype strains were isolated and identified from Yunnan Saba pigs. The genomic DNA of all isolated superior serotypes of E. coli was obtained. Five major high pathogenicity island (HPI) structural genes (irp1, irp2, irp3, irp4 and irp5) were cloned, sequenced and referenced with GenBank database. The sequence identities of irp1, irp2, irp3, irp4 and irp5 with GenBank were 98 %, 99 %, 99 %, 98 %, and 99 %, respectively. Forty-four E. coli isolates characterized similarity with enteroinvasive E. coli (EIEC), uropathogenic E. coli (UPEC), Y. pestis and enteropathogenic E. coli (EPEC). The secondary and tertiary structures of high molecular weight proteins (HMWPs), encoded by five structural genes, were predicted using bioinformatics tools. These proteins had differences in random curls, α-helix and slight amount of β-sheet. After validation, 10 iron deficient isolates expressed the ferritin HMWPs similar to those of Yersinia. Later on, Kunming mice were infected with E. coli HPI+ and HPI- strains, respectively for the histopathology examination. The higher organ damage was observed by E. coli HPI+ than HPI- strain in mice. This study postulates the predicted protein structures of major genes, and validates the HMWP expression under iron starvation and provides a theoretical basis for prevention and treatment of E. coli related diseases.
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