Kinetic and Crystallographic Studies of Extended-Spectrum GES-11, GES-12, and GES-14 β-Lactamases

Kinetic and crystallographic studies of extended-spectrum GES-11, GES-12, and GES-14 β-lactamases.

GES-1 is a class A extended-spectrum β-lactamase conferring resistance to penicillins, narrow- and expanded-spectrum cephalosporins, and ceftazidime. However, GES-1 poorly hydrolyzes aztreonam and cephamycins and exhibits very low k(cat) values for carbapenems. Twenty-two GES variants have been discovered thus far, differing from each other by 1 to 3 amino acid substitutions that affect substra...

Nomenclature of GES-Type Extended-Spectrum -Lactamases

In two recently published articles, Wachino et al. designated a novel ceftazidime-hydrolyzing class A extended-spectrum -lactamase (ESBL) (GES-a) as GES-3 (4), and a new cephamycin-hydrolyzing and inhibitor-resistant class A ESBL (GESb) as GES-4 (5). In actuality, their articles are fraught with misleading nomenclature of GES-type ESBLs and controvertible conclusions on the relationship between...

Kinetic and Structural Requirements for Carbapenemase Activity in GES-Type β-Lactamases

Carbapenems are the last resort antibiotics for treatment of life-threatening infections. The GES β-lactamases are important contributors to carbapenem resistance in clinical bacterial pathogens. A single amino acid difference at position 170 of the GES-1, GES-2, and GES-5 enzymes is responsible for the expansion of their substrate profile to include carbapenem antibiotics. This highlights the ...

First outbreak of Klebsiella pneumoniae clinical isolates producing GES-5 and SHV-12 extended-spectrum beta-lactamases in Korea.

GES-11, a novel integron-associated GES variant in Acinetobacter baumannii.

New extended-spectrum beta-lactamase GES-11 was detected in Acinetobacter baumannii BM4674. The enzyme conferred resistance to beta-lactams, including aztreonam, and reduced susceptibility to carbapenems. The structural gene was part of a class 1 integron borne by self-transferable plasmid pIP847. GES-type beta-lactamases have not been reported previously in A. baumannii.