PER-7, an extended-spectrum beta-lactamase with increased activity toward broad-spectrum cephalosporins in Acinetobacter baumannii

Acinetobacter baumannii isolate AP2 was recovered from a bronchial lavage sample of a patient hospitalized in Paris, France. A. baumannii AP2 was resistant to all β-lactams, including carbapenems, and expressed the extended-spectrum β-lactamase (ESBL) PER-7, which differs from PER-1 by 4 amino acid substitutions. Compared to PER-1, PER-7 possessed higher-level hydrolytic activities against cephalosporins and aztreonam. The blaPER-7 gene was chromosomally located and associated with a mosaic class 1 integron structure. Additionally, isolate AP2 expressed the carbapenem-hydrolyzing oxacillinase OXA-23 and the 16S RNA methylase ArmA, conferring high-level resistance to aminoglycosides.