The Class D, or OXA, ß-lactamases, first noted for their ability to hydrolyze oxacillin, hydrolyze a wide range of ß-lactam antibiotics. Phylogenetic analysis shows that these genes were mobilized from chromosomes to plasmids on three different occasions, one (Node A)recently, one (Node B) about 42 million years ago, and one (Node C) about 116 million years ago.

Click here to download the Class D phylogeny with a key that includes accession numbers. Click here to download the paper in which the phylogeny was published.