3 IS-RFLP: A Powerful Tool for Geographical Clustering of Global Isolates of Yersinia pestis

Multiple copies of several classes of insertion sequences (IS) are found in the genome of Yersinia pestis, the causative agent of bubonic and pneumonic plague. We used the genetic instability generated by these IS to develop a method (designated 3IS-RFLP) based on the restriction fragment length polymorphism of the IS100, IS285 and Is1541 elements for studying Y. pestis strains of worldwide origin. We show that 3IS-RFLP is a powerful tool to group Y. pestis isolates according to their geographical origin, and therefore that this method may be valuable for investigating the origin of new or re-emerging plague foci or for addressing forensic issues.