Biochemical Characterization of PER-2 and Genetic Environment of bla _PER-2

Abstract

PER-2 was the first detected and the second most prevalent extended-spectrum ␤-lactamase in clinical pathogens isolated in Argentina and was also reported only in other South American countries. Citrobacter freundii 33587 was isolated in 1999 in Buenos Aires and was resistant to all tested ␤-lactams except cephamycins and carbapenems. The strain produced both plasmid-borne TEM-1 and PER-2 (pI 5.4), which could be transferred by conjugation. By PCR screening, thermal asymmetric interlaced PCR, and DNA sequencing, we detected an ISPa12/IS1387a insertion sequence upstream of bla PER-2 , previously reported as also being associated with bla PER-1 . The presence of similar structures upstream of bla PER-1 and bla PER-2 suggests a common origin and mobilization. Compared to bla PER-1 genes, an additional putative promoter for bla PER-2 was found. PER-2 kinetic analysis showed its high hydrolysis efficiencies toward both CTX and CAZ (k cat /K m , 0.76 and 0.43 M ؊1 ⅐ s ؊1 , respectively).

Exploring the Landscape of Diazabicyclooctane (DBO) Inhibition: Avibactam Inactivation of PER-2 β-Lactamase

“…PER ␤-lactamases are also inhibited by mechanism-based inhibitors such as clavulanate and tazobactam (3,4). Recently, the X-ray crystal structure of PER-2 was determined at 2.2 Å (5).…”

Susceptibility, phenotypes of resistance, and extended-spectrum β-lactamases in Acinetobacter baumannii strains

“…PER-1 producing Acinetobacter baumannii has been reported from France, Belgium, Romania, Russia and Hungary [10,19,[27][28][29]. Subsequent variants have been described in the PER family in various bacteria (also in A. baumannii), among which PER-2 is found to predominate in some South American countries [30,31]. Most strains of A. baumannii with the bla PER-1 gene, investigated in various countries, do not exhibit a consanguineous relationship to one another, something that is suggested by a clonal model of spread of this mechanism of resistance [9,11].…”

Crystal Structure of the Extended-Spectrum β-Lactamase PER-2 and Insights into the Role of Specific Residues in the Interaction with β-Lactams and β-Lactamase Inhibitors

“…Escherichia coli TC9 is a transconjugant clone harboring the pCf587 plasmid, used as the source of the bla PER-2 gene (12). Escherichia coli Top10F= (Invitrogen, USA) and Escherichia coli BL21(DE3) (Novagen, USA) were hosts for transformation experiments.…”

“…PER-2 shares 88% amino acid sequence identity with mature PER-1 and both of them display high catalytic efficiencies (k cat /K m ) toward most ␤-lactams, generally characterized by similar values for both ceftazidime and cefotaxime, although for PER-2 the values seem to be nearly one order of magnitude higher than those for PER-1 (12,13). PER-2 is also strongly inhibited by mechanism-based inhibitors such as clavulanate and tazobactam (12).…”

“…PER-2 is also strongly inhibited by mechanism-based inhibitors such as clavulanate and tazobactam (12).…”