IS 26 Family Members IS 257 and IS 1216 Also Form Cointegrates by Copy-In and Targeted Conservative Routes

Abstract

IS 26 differs from other studied ISs in the reactions that it can undertake. The differences make IS 26 uniquely suited to its key role in the recruitment and spread of antibiotic resistance genes in Gram-negative bacteria. However, whether other ISs in the IS 6 /IS 26 family can perform the same reactions is not known. IS 257 /IS 431 and IS 1216 isoforms found associated with antibiotic resistance genes in the Gram-positive bacteria staphylococci, enterococci, streptococci, and clostridia are related to IS 26 . However, the way that they move had not been investigated, limiting interpretation of their role in resistance gene dissemination and in the formation of cointegrates and complex resistance regions in staphylococci and enterococci. Here, they are shown to share the broad catalytic capabilities of IS 26 , demonstrating that it is likely that all members of the redefined IS 6 /IS 26 family of bacterial ISs likewise are able to use both the copy-in and conservative routes.