Spread, persistence and novel strategies to combat antimicrobial resistance in Enterococcus faecium
1. The predominance of a vanB E. faecium clone involved in the large Swedish outbreak is due to combinations of a successful lineage of E. faecium with persistent mobile genetic elements containing the vancomycin resistance determinant.
The selected vancomycin resistant (VRE) and susceptible Enterococcus faecium isolates from the dominant clone causing a widespread outbreak in Swedish hospitals in 2007-9 are ampicillin- and high-level ciprofloxacin resistant, belong to the successful genogroup CC17 and harbour 6-11 virulence genes associated with this genogroup. All VRE-isolates harbour the most predominant vanB subtype as an integral part of conjugative transposon Tn5382 on a ~70kb pRUM replicon including an axe-txe segregation stability module. The plasmid is transferable (rates 10-8 to 10-12) and transferability increases (rates 10-3-10-5) in retransfer experiments after the plasmid (~140kb) has picked up additional genetic material.
2. Anti-RNA strategies for regulation of gene expression in enterococci could be an innovative tool for functional genomic research with a therapeutic potential.
A gene-specific anti-RNA oligo shows promising results reducing the expression of vancomycin resistance (vanB2) 8-fold in E.faecium. The technology needs more testing with other concentrations, oligos and strains to get a larger reduction of expression and to resolve problems with toxicity of the tested unspecific anti-RNA oligo.
Våre preliminære data som viser at en gen-spesifikke anti-RNA oligo reduserer uttrykk av vancomycin resistens hos et enterokokk isolat 8-fold viser at anti-RNA strategier for regulering av genuttrykk i enterokokker og andre Gram-positive bakterier er mulig, men teknikken må selvfølgelig forbedres samt at problemet med levering av anti-RNA oligo til infeksjonsstedet må løses hvis teknikken skal kunne ha et potensiale i behandling av bakterielle infeksjoner.
The widespread VRE outbreak in Swedish hospitals 2007-2009 was associated with clonal E. faecium CC17 genogroup strains...
21st European Congress of Clinical Microbiology and Infectious Diseases, Milano, Italy.