Nonconjugative transposition of the vanB-containing Tn5382-like element in Enterococcus faecium

Abstract

The vanB2 operon encoding glycopeptide resistance is an integral part of the putative conjugative transposon Tn5382. Characterization of clinical glycopeptide resistant derivatives from an epidemic ampicillin-resistant Enterococcus faecium strain showed precise chromosomal or plasmid insertions of a vanB2-containing Tn5382-like element. Conjugative transposition of the Tn5382-like element was not demonstrated in retransfer studies.

FIG. 1.

PFGE of SmaI-digested total DNAs of four vancomycin-resistant strains and the prototype ampicillin-resistant E. faecium outbreak strain (TUH2-21) (A) and corresponding Southern hybridization with a vanB probe (B), a Tn5382 probe (C), and an IS1216V probe (D). Lanes: 1, low-range PFGE marker (New England Biolabs); 2, TUH2-21; 3, TUH2-20; 4, TUH2-18; 5, TUH2-19; 6, TUH2-55.

FIG. 2.

Target sequence at the site of integration of the Tn5382-like transposon into the chromosome of TUH2-18 and in a plasmid in TUH2-19. The nucleotide sequences of the Tn5382-like elements chromosomally located in TUH2-18 (A) and plasmid borne in TUH2-19 (B) were aligned with the target sequence in TUH2-21. Tn5382-like element inverted repeats are in bold letters. The 6-bp coupling sequence is underlined.