A new Bacteroides fragilis insertion sequence (IS)-like element has been identified, cloned, and sequenced. The element is 1598 base pairs in length. It is flanked by a 15-base pair imperfect inverted repeat and contains a large open reading frame which could encode a 430 amino acid protein. There is an 8-base pair duplication of genomic DNA sequences at the site of integration. One copy of the IS-like element is integrated within the 5' upstream sequence of the metallo-beta-lactamase gene ccrA, cloned from B. fragilis TAL3636. The IS-like element is integrated 19 bp upstream of the predicted initiation codon and, therefore, probably provides the transcriptional start signals for the CcrA gene.