A Novel Integron in Salmonella enterica Serovar Enteritidis, Carrying the bla(DHA-1) Gene and Its Regulator Gene ampR, Originated from Morganella morganii

The genetic organization of the gene coding for DHA-1 and the corresponding ampR gene was determined by PCR mapping. These genes have been mobilized from the Morganella morganii chromosome and inserted into a complex sulI-type integron, similar to In6 and In7. However, they are not themselves mobile cassettes. This integron probably includes a specific site for recombination allowing the mobilization of diverse resistance genes, as observed for bla(CMY-1) and bla(MOX-1).