Novel Streptomycin and Spectinomycin Resistance Gene as a Gene Cassette within a Class 1 Integron Isolated from Escherichia coli

The aadA genes, encoding resistance to streptomycin and spectinomycin, have been found as gene cassettes in different gram-negative and gram-positive bacterial species. The present study has revealed the sequence of a new gene, aadA5, integrated as a gene cassette together with the trimethoprim resistance gene dfr7 in a class 1 integron. The integron was located on a plasmid and was identified in a pathogenic porcine Escherichia coli isolate.