Bacteria that simultaneously produce multiple extended-spectrum beta-lactamases are frequently isolated. We report an Enterobacter cloacae isolate, ES24, producing four different beta-lactamases (AmpC type beta-lactamase, TEM-1, SHV-7, and a novel extended-spectrum beta-lactamase, SHV-30). Direct sequencing of bla(SHV) gene products gave a "double peak" at position 703, suggesting the presence ...

Eighty-five extended-spectrum beta-lactamase-producing Enterobacteriaceae from a Slovak hospital have been studied. SHV-2a was predominant, but other variants have been detected, namely, SHV-5, SHV-12, TEM-12, TEM-15, and TEM-132, which differed from TEM-1 by amino acid substitutions R164H, E240K, and I173V and had kinetic properties similar to those of TEM-28.

Boronic acid transition state inhibitors (BATSIs) with R1 side chains of cefotaxime and ceftazidime were assayed against SHV-1, SHV-2, SHV-5, D104K, and D104K G238S beta-lactamases. The D104K variant was the most susceptible to inhibition by the ceftazidime BATSI (Ki, 730+/-80 nM), while the D104K G238S variant was the most susceptible to the cefotaxime BATSI (Ki, 1.1+/-0.2 microM).

Plasmid-encoded resistance to broad-spectrum cephalosporins and aztreonam is becoming a widespread phenomenon in clinical medicine. These antibiotics are inactivated by an array of different extended-spectrum beta-lactamases (ESBLs) which have evolved by point mutations of parental TEM or SHV beta-lactamases. In a previous study conducted during 1994-1995, SHV-2, SHV-2a and SHV-5 beta-lactamase...

Introduction: Extended-spectrum beta-lactamases (ESBLs) are rapidly evolving group of beta-lactamase enzymes commonly produced by the Gram negative bacteria, these enzymes have been derived from TEM and SHV genes by mutations. This study was done to look for TEM and SHV genes in ESBL positive E.coli and K. pneumoniae isolated from the cancer patients suffering with infections and admitted in a ...

Extended-spectrum beta-lactamases (ESBLs) emerge by point mutation from non-extended-spectrum precursors. The aims of this study were to reveal the basis for variations in resistance levels found in a collection of 21 Klebsiella pneumoniae clinical isolates from Brisbane, Australia. Previous studies have shown that 20 of these isolates possess bla(SHV-11), bla(SHV-2a), and/or bla(SHV-12), and t...