The current ICE age: Biology and evolution of SXT-related integrating conjugative elements

SXT is an integrating Conjugative element (ICE) that was initially isolated from a 1992 Vibrio cholerae 0 139 clinical isolate from India. This similar to 100-kb ICE encodes resistance to multiple antibiotics. SXT or closely related ICEs are now present in most clinical and some environmental V. cholerae isolates from Asia and Africa. SXT-related ICEs are not limited to V. cholerae. It is now clear that so-called IncJ elements such its R391 are closely related to SXT. More than 25 members of the SXT/R391 family of ICEs have now been identified in environmental and clinical isolates of diverse species of gamma-proteobacteria worldwide. In this review, we discuss the diversity, evolution and biology of this family of ICEs. (c) 2006 Elsevier Inc. All rights reserved.