Sequence Analysis of ARI-1, a Novel OXA β-Lactamase, Responsible for Imipenem Resistance in Acinetobacter baumannii 6B92

The sequence of the bla(ARI-1) gene from imipenem-resistant Acinetobacter baumannii 6B92 has been determined. The structural gene encodes a 273-amino-acid protein which is most related to the OXA class D beta-lactamases. The conserved S-T-F-K and K-T-G motifs were identified in the ARI-1 protein sequence, also named OXA-23, but significantly, a point mutation (Y-->F) was identified in the Y-G-N conserved motif, also known to function in the active site.