Molecular characterization of the vanD gene cluster and a novel insertion element in a vancomycin-resistant enterococcus isolated in Canada

A single vanD-containing Enterococcus faecium strain (N97-330) was isolated in Canada. The vanD-containing region was cloned and sequenced. Although t he proteins have more than 96% identity to a previously described vanD regi on in BM4339, the vanS(D) gene contains a frameshift mutation that leads to a predicted truncated protein. Furthermore, sequence analysis of the ddl g ene revealed the presence of an IS982-like element (ISEfm1) which interrupt ed the D-Ala-D-Ala ligase. This suggested the constitutive expression of th e vanD operon, which was confirmed. Pulsed-field gel electrophoresis finger printing demonstrated that BM-4339 was not related to N97-330 (>15 band dif ferences). Both strains contained multiple copies of the IS982-like element .