Dissemination of sul3-containing elements linked to class 1 integrons with an unusual 3′ conserved sequence region among Salmonella isolates

A sul3 domain (IS440-sul3-orf1-IS26) was found linked to an unusual 3' conserved sequence region (qacH) of class 1 integrons and detected among nontyphoid Salmonella isolates (n = 47) from different sources. Three types of integrons differing in the gene cassette array (dfrA12-orfF-aadA2-cmlA1-aadA1, dfrA12-orfF-aadA2-1, and estX-psp-aadA2-cmlA1-aadA1) were found associated with this sul3 domain. They were associated with particular clones and specific high-molecular-weight plasmids.