A study designed to gain baseline information on strains of Escherichia coli displaying resistance to cefoxitin in Canada is described. A total of 29,323 E. coli isolates were screened at 12 participating hospital sites as part of an extended-spectrum beta-lactamase surveillance initiative. A total of 411 clinically significant, nonrepeat isolates displaying reduced susceptibilities to the NCCL...

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 ...

AmpC is a class C Ambler β-lactamase that confers resistance to cephamycins. Globally reported AmpC-producing Enterobacterales are clinically important due their therapeutic restrictions and epidemiology. Between April 2021 May 2021, an outbreak of beta-lactamase-producing Escherichia coli occurred at Showa University Hospital. Because this outbreak, plasmid typing, enterobacterial repetitive i...

The in vivo efficacy of piperacillin in combination with the penem inhibitor BLI-489 was determined using acute lethal systemic infections in mice. On the basis of preliminary results with various ratios, a dosing ratio of 8:1 was found to be optimal for retention of enhanced efficacy. Piperacillin-BLI-489 dosed at an 8:1 ratio was efficacious against murine infections caused by class A (includ...

BACKGROUND The beta-lactamase landscape is changing radically, with CTX-M types now the most prevalent extended-spectrum beta-lactamases (ESBLs) worldwide, except maybe in the USA. In addition, there are growing numbers of Enterobacteriaceae with KPC and metallo-carbapenemases. We examined whether combinations of oxyimino-cephalosporins with NXL104, a novel non-beta-lactam beta-lactamase inhibi...

BACKGROUND Knowledge of the clinical features of infections caused by Escherichia coli strains that produce plasmid-mediated AmpC beta-lactamase is limited. Of the several groups of plasmid-mediated AmpC beta-lactamases, CMY-type beta-lactamase is the most common in the United States. METHODS We prospectively identified patients infected or colonized with E. coli strains that produce CMY-type...

Lys67 is essential for the hydrolysis reaction mediated by class C beta-lactamases. Its exact catalytic role lies at the center of several different proposed reaction mechanisms, particularly for the deacylation step, and has been intensely debated. Whereas a conjugate base hypothesis postulates that a neutral Lys67 and Tyr150 act together to deprotonate the deacylating water, previous experime...