Biochemical-genetic characterization and distribution of OXA-22, a chromosomal and inducible class D β-lactamase from Ralstonia (Pseudomonas) pickettii

Front genomic DNA of Ralstonia pickettii isolate PIC-1, a beta-lactamase gene was cloned that encodes the oxacillinase OXA-22, It differs from known oxacillinases, being most closely related to OXA-9 (38% amino acid identity). The hydrolytic spectrum of OXA-22 is limited mostly to benzylpenicillin, cloxacillin, and restricted-spectrum cephalosporins. OXA-22-like genes were identified as single chromosomal copies in five other R. pickettii clinical isolates, The expression of OXA-22-like beta-lactamases was inducible in R, pickettii.