Integrative conjugative elements and related elements are major contributors to the genome diversity of Streptococcus agalactiae

Thirty-five putative integrative conjugative elements and related elements were identified at 15 locations in the eight sequenced genomes of Streptococcus agalactiae. Twelve are composite, likely resulting from site-specific accretions. Circular forms were detected for five elements. Macroarray analysis confirmed their high plasticity and wide distribution in S. agalactiae.