Presence of a vanA-carrying pheromone response plasmid (pBRG1) in a clinical isolate of Enterococcus faecium.

TitlePresence of a vanA-carrying pheromone response plasmid (pBRG1) in a clinical isolate of Enterococcus faecium.
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2003
AuthorsMagi, Gloria, Capretti Roberta, Paoletti Claudia, Pietrella Marco, Ferrante Luigi, Biavasco Francesca, Varaldo Pietro Emanuele, and Facinelli Bruna
JournalAntimicrobial agents and chemotherapy
Volume47
Pagination1571-6
Date Published2003 May
ISSN0066-4804
KeywordsBacterial Adhesion, Bacterial Proteins, Caco-2 Cells, Carbon-Oxygen Ligases, Conjugation, Enterococcus faecium, Genetic, Humans, Oligopeptides, Pheromones, Plasmids
Abstract

Sex pheromone plasmids, frequently found in Enterococcus faecalis, have rarely been detected in Enterococcus faecium. pBRG1 is an approximately 50-kb vanA-carrying conjugative plasmid of an E. faecium clinical isolate (LS10) that is transferable to E. faecalis laboratory strains. In cell infection experiments, E. faecium LS10 exhibited remarkably high invasion efficiency and produced cytopathogenic effects in Caco-2 cell monolayers. Growth in the presence of sex pheromones produced by E. faecalis JH2-2 was found to cause self-aggregation of both E. faecium LS10 and E. faecalis JH-RFV(pBRG1) (a transconjugant obtained by transfer of pBRG1 to E. faecalis JH2-2) and to increase the cell adhesion and invasion efficiencies of both E. faecium LS10 and E. faecalis JH-RFV(pBRG1). Sex pheromone cCF10 caused clumping of E. faecalis OG1RF(pBRG1) (a transconjugant obtained by transfer of pBRG1 to E. faecalis OG1RF) at a concentration approximately 100-fold higher than the one required for the control strain E. faecalis OG1RF(pCF10). PCR products of the expected sizes were obtained with primers internal to aggregation substance genes of E. faecalis pheromone response plasmids pAD1, pPD1, and pCF10 and primers internal to ash701 of E. faecium pheromone plasmid pHKK701. These findings suggest that pBRG1 of E. faecium LS10 is a sex pheromone response plasmid.