genomes

Enterococci form part of our natural intestinal flora, but also cause antibiotic-resistant infections in hospitals. In the June 13 Nature, Nathan Shankar and colleagues describe an analysis of different Enterococcus faecalis strains, one from a hospital ward outbreak in the mid-1980s, MMH594, and the other from the first vancomycin-resistant isolate, V583 (Nature 2002, 417:746-750).

Genomic comparisons revealed that the V583 isolate lacks a 17 kb region containing virulence genes, such as the cytolysin operon. Further comparison with the sequence of the non-infection-derived OG1 strain showed that the clinical isolates have a genomic insertion of around 150 kb. This element contains over one hundred genes encoding transposases, transcriptional regulators and virulence-associated proteins. The characterization of this novel pathogenicity island should be of benefit for diagnosis and for the identification of new drug targets.