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The Yersinia high-pathogenicity island
1Laboratoire des Yersinia, Institut Pasteur, Paris, France. carniel2@pasteur.fr
Abstract:
A pathogenicity island present only in highly pathogenic strains of Yersinia (Y. enterocolitica 1B, Y. pseudotuberculosis I and Y. pestis) has been identified on the chromosome of Yersinia spp. and has been designated High-Pathogenicity Island (HPI). The Yersinia HPI carries a cluster of genes involved in the biosynthesis, transport and regulation of the siderophore yersiniabactin. The major function of this island is thus to acquire iron molecules essential for in vivo bacterial growth and dissemination. The presence of an integrase gene and att sites homologous to those of phage P4, together with a G + C content much higher than the chromosomal background, suggests that the HPI is of foreign origin and has been acquired by chromosomal integration of a phage. The HPI can excise from the chromosome of Y. pseudotuberculosis and is found inserted into any of the three copies of the asn tRNA loci present in this species. A unique characteristic of the HPI is its wide distribution in various enterobacteria. Although first identified in Yersinia spp., it has subsequently been detected in other genera such as E. coli, Klebsiella and Citrobacter.
Insights
The High-Pathogenicity Island (HPI) in Yersinia bacteria facilitates iron acquisition for growth and spread. This mobile genetic element, likely acquired via phage, is also found in other enterobacteria like E. coli.
Area of Science:
- Microbiology
- Genetics
- Bacterial Pathogenesis
Background:
- The High-Pathogenicity Island (HPI) is a distinct genomic region found in virulent Yersinia strains.
- The HPI harbors genes crucial for yersiniabactin siderophore metabolism, essential for iron uptake.
Purpose of the Study:
- To characterize the High-Pathogenicity Island (HPI) in Yersinia species.
- To investigate the origin and distribution of the HPI in enterobacteria.
Main Methods:
- Genomic analysis to identify the HPI and its associated genes.
- Comparative genomics to assess HPI distribution across different bacterial genera.
- Investigation of HPI integration sites within the bacterial chromosome.
Main Results:
- The HPI contains a gene cluster for yersiniabactin siderophore biosynthesis and transport.
- Evidence suggests the HPI was acquired through phage integration, indicated by an integrase gene and att sites.
- The HPI is present in highly pathogenic Yersinia strains (Y. enterocolitica 1B, Y. pseudotuberculosis I, Y. pestis) and can excise from the chromosome.
- The HPI is found inserted into asn tRNA loci and exhibits wide distribution in other enterobacteria, including E. coli, Klebsiella, and Citrobacter.
Conclusions:
- The HPI is a key virulence factor enabling Yersinia to acquire iron for in vivo growth.
- The HPI's foreign origin and mobility contribute to its dissemination among enterobacteria, impacting bacterial pathogenicity.