PME-1, an Extended-Spectrum β-Lactamase Identified in Pseudomonas aeruginosa
ABSTRACTA novel extended-spectrum β-lactamase (ESBL) was identified in aPseudomonas aeruginosaclinical isolate obtained from a patient admitted to a hospital in Pennsylvania in 2008. The patient had a prolonged hospitalization in a hospital in Dubai, United Arab Emirates, before being transferred to the United States. The novel ESBL, designated PME-1 (Pseudomonas aeruginosaESBL 1), is a molecular class A, Bush-Jacoby-Medeiros group 2be enzyme and shared 50, 43, and 41% amino acid identity with the L2 β-lactamase ofStenotrophomonas maltophilia, CTX-M-9, and KPC-2, respectively. PME-1 conferred clinically relevant resistance to ceftazidime, cefotaxime, cefepime, and aztreonam inP. aeruginosaPAO1 but not to carbapenems. Purified PME-1 showed good hydrolytic activity against ceftazidime, cefotaxime, and aztreonam, while activity against carbapenems and cefepime could not be measured. PME-1 was inhibited well by β-lactamase inhibitors, including clavulanic acid, sulbactam, and tazobactam. TheblaPME-1gene was carried by an approximately 9-kb plasmid and flanked by tandem ISCR24elements.