Prevalent chromosome fusion inVibrio choleraeO1

Two circular chromosomes are a defining feature of the family Vibrionaceae , including the pathogen Vibrio cholerae , with rare reports of isolates with a single, fused chromosome. Here we report chromosome fusions in clinical V. cholerae O1 isolates, including several independent fusion events stable enough to be transmitted between patients within a household. Fusion occurs in a 12 kilobase-pair homologous sequence shared between the two chromosomes, which may lead to reversible chromosomal fusion.