BACKGROUND Extended-spectrum AmpC (ESAC) β-lactamase enzymes, which are either chromosomally encoded or plasmid encoded, have minor structural changes that broaden their substrate hydrolysis profile. The derepressed AmpC enzyme found once in Enterobacter cloacae CHE was shown to contain a six residue deletion in the H-10 helix in close proximity to the active site. Avibactam is a non-β-lactam i...

Metallo-beta-lactamases are zinc enzymes able to hydrolyze the four-membered ring of beta-lactam antibiotics, representing one of the latest generations of beta-lactamases. These enzymes belong to the zinc metallo-hydrolase family of the beta-lactamase fold. Enzymes belonging to this family have a bimetallic active site whose structure varies among different members by point substitutions of th...

Cultures of Yersinia enterocolitica grown at 22 degrees C produced beta-lactamases, whereas cultures grown at 37 degrees C produced these enzymes much less effectively. Both dicloxacillin and clavulanic acid inhibited the beta-lactamase activity of bacterial crude extracts and potentiated the activity of penicillin G or cephalothin against 14 Y. enterocolitica strains. It appeared that the beta...

AIM the goal of this study is to understand the phenotype characteristic of beta-lactamase enzymes producing Enterobacteriaceae, such as ESBL, AmpC, and carbapenemase. METHODS three different methods are performed to confirm those phenotypic characteristics, namely double disk diffusion method to confirm ESBL, AmpC disk test (cefoxitin-based) to confirm AmpC, and modified Hodge test to confir...

This work describes a simple and practical double synergy differential test (DSDT) that couples the detection of ESBLs and AmpC-type enzymes by means of a combo-disk approach using cefotaxime and ceftazidime as indicator substrates, and clavulanate and boronic acid as enzyme inhibitors. The DSDT was tested with a collection of 118 Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis st...

CPS-1 is a subclass B3 metallo-β-lactamase from a Chryseobacterium piscium isolate collected from soil, showing 68% amino acid identity to the GOB-1 enzyme. CPS-1 was overproduced in Escherichia coli Rosetta (DE3), purified by chromatography, and biochemically characterized. This enzyme exhibits a broad-spectrum substrate profile, including penicillins, cephalosporins, and carbapenems, which ov...

ß-Lactams are the most widely used antibiotics, and ß-lactamases are the greatest source of resistance to them. Colorimetric tests are good, rapid, indicators of ß-lactamase production and its contingent resistance in Haemophilus, Moraxella and Neisseria spp. They can also be applied to Gram-negative bacilli but are less useful, since the usual question is not whether a ß-lactamase is produced ...

There has been greater interest in developing additional antimicrobial agents due to the increasing health care costs and resistance resulting from bacterial pathogens to currently available treatment options. Gram-negative organisms including Enterobacteriaceae and Pseudomonas aeruginosa are some of the most concerning threats due to their resistance mechanisms: extended-spectrum beta-lactamas...

Since antibiotics were first used, each new introduced class has been followed by a global wave of emergent resistance, largely originating in Europe and North America where they were first used. Methicillin-resistant Staphylococcus aureus spread from the United Kingdom and North America across Europe and then Asia over more than a decade. Vancomycin-resistant enterococci and Klebsiella pneumon...