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Enterococcus faecalis/ faecium repeats (EFARs) are miniature insertion sequences spread in the genome of Enterococcus faecalis and Enterococcus faecium. Unit-length repeats measure 165–170 bp and contain two modules (B and T) capable of folding independently into stem-loop sequences, connected by a short, unstructured module J. The E. faecalis elements feature only one type of B, J and T modules. In contrast, the E. faecium elements result from the assembly of different types of B, J and T modules, and may vary in length because they carry multiple B modules. Most EFARs are located close (0–20 bp) to ORF stop codons, and are thus cotranscribed with upstream flanking genes. In both E. faecalis and E. faecium cells, EFAR transcripts accumulate in a strand-dependent fashion. Data suggest that T modules function as bidirectional transcriptional terminators, which provide a 3′-end to gene transcripts spanning B modules, while blocking antisense transcripts coming in from the opposite direction. [ABSTRACT FROM AUTHOR]