Recombination between the dfrA12 -orfF- aadA2 Cassette Array and an aadA1 Gene Cassette Creates a Hybrid Cassette, aadA8b

Homologous recombination between closely related gene cassettes, such as aadA1 and aadA2, which are 89% identical, can create hybrid cassettes and hybrids of existing cassette arrays. A new cassette array, dfrA12-orfF-aadA8b, which was created by such a recombination event occurring within the aadA2 cassette in the dfrA12-orfF-aadA2 array, has been identified.