Unusual class 1 integron-associated gene cassette configuration found in IncA/C plasmids from Salmonella enterica

IncA/C plasmids carrying an unusual cassette configuration in a class 1 integron and five further shared resistance genes, aacC4 , aphA1 , hph , sul2 , and tetA (D) were found in Salmonella enterica serovars Senftenberg and Ohio. A deletion formed using a short region of homology in the 5′ conserved segment and the orfF cassette created an array with only part of orfF followed by the aadA2 cassette. The IncA/C plasmids were not recoverable by conjugation, but additional conjugative resistance plasmids were present in some strains.