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Mechanism of chromosomal transfer of Enterococcus faecalis pathogenicity island, capsule, antimicrobial resistance, and other traits.

ABSTRACT: The Enterococcus faecalis pathogenicity island (PAI) encodes known virulence traits and >100 additional genes with unknown roles in enterococcal biology. Phage-related integration and excision genes, and direct repeats flanking the island, suggest it moves as an integrative conjugative element (ICE). However, transfer was observed not to require these genes. Transfer only occurred from donors possessing a pheromone responsive-type of conjugative plasmid, and was invariably accompanied by transfer of flanking donor chromosome sequences. Deletion of plasmid transfer functions, including the cis-acting origin of transfer (oriT), abolished movement. In addition to demonstrating PAI movement by a mechanism involving plasmid integration, we observed transfer of a selectable marker placed virtually anywhere on the chromosome. Transfer of this selectable marker was observed to be accompanied by chromosome-chromosome transfer of vancomycin resistance, MLST markers, and capsule genes as well. Plasmid mobilization therefore appears to be a major mechanism for horizontal gene transfer in the evolution of antibiotic resistant E. faecalis strains capable of causing human infection.

SUBMITTER: Manson JM

PROVIDER: S-EPMC2901427 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature

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Mechanism of chromosomal transfer of Enterococcus faecalis pathogenicity island, capsule, antimicrobial resistance, and other traits.

Manson Janet M JM Hancock Lynn E LE Gilmore Michael S MS

Proceedings of the National Academy of Sciences of the United States of America 20100621 27

The Enterococcus faecalis pathogenicity island (PAI) encodes known virulence traits and >100 additional genes with unknown roles in enterococcal biology. Phage-related integration and excision genes, and direct repeats flanking the island, suggest it moves as an integrative conjugative element (ICE). However, transfer was observed not to require these genes. Transfer only occurred from donors possessing a pheromone responsive-type of conjugative plasmid, and was invariably accompanied by transfe ...[more]

PMID: 20566881

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Project description:Enterococci are the third leading cause of hospital associated infections and have gained increased importance due to their fast adaptation to the clinical environment by acquisition of antibiotic resistance and pathogenicity traits. Enterococcus faecalis harbours a pathogenicity island (PAI) of 153 kb containing several virulence factors including the enterococcal surface protein (esp). Until now only internal fragments of the PAI or larger chromosomal regions containing it have been transferred. Here we demonstrate precise excision, circularization and horizontal transfer of the entire PAI element from the chromosome of E. faecalis strain UW3114. This PAI (ca. 200 kb) contained some deletions and insertions as compared to the PAI of the reference strain MMH594, transferred precisely and integrated site-specifically into the chromosome of E. faecalis (intergenic region) and Enterococcus faecium (tRNAlys). The internal PAI structure was maintained after transfer. We assessed phenotypic changes accompanying acquisition of the PAI and expression of some of its determinants. The esp gene is expressed on the surface of donor and both transconjugants. Biofilm formation and cytolytic activity were enhanced in E. faecalis transconjugants after acquisition of the PAI. No differences in pathogenicity of E. faecalis were detected using a mouse bacteraemia and a mouse peritonitis models (tail vein and intraperitoneal injection). A 66 kb conjugative pheromone-responsive plasmid encoding erm(B) (pLG2) that was transferred in parallel with the PAI was sequenced. pLG2 is a pheromone responsive plasmid that probably promotes the PAI horizontal transfer, encodes antibiotic resistance features and contains complete replication and conjugation modules of enterococcal origin in a mosaic-like composition. The E. faecalis PAI can undergo precise intra- and interspecies transfer probably with the help of conjugative elements like conjugative resistance plasmids, supporting the role of horizontal gene transfer and antibiotic selective pressure in the successful establishment of certain enterococci as nosocomial pathogens.

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Dataset Information

Mechanism of chromosomal transfer of Enterococcus faecalis pathogenicity island, capsule, antimicrobial resistance, and other traits.

Publications

Mechanism of chromosomal transfer of Enterococcus faecalis pathogenicity island, capsule, antimicrobial resistance, and other traits.

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