scholarly journals Probing the Mechanism of Inactivation of the FOX-4 Cephamycinase by Avibactam

2018 ◽  
Vol 62 (5) ◽  
pp. e02371-17 ◽  
Author(s):  
Michiyoshi Nukaga ◽  
Krisztina M. Papp-Wallace ◽  
Tyuji Hoshino ◽  
Scott T. Lefurgy ◽  
Christopher R. Bethel ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Single Amino Acid ◽  
Content Type ◽  
Class A ◽  
Hydrogen Bonding Interactions ◽  
Extended Spectrum ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor ◽  
Inhibition Analysis

ABSTRACTCeftazidime-avibactam is a “second-generation” β-lactam–β-lactamase inhibitor combination that is effective againstEnterobacteriaceaeexpressing class A extended-spectrum β-lactamases, class A carbapenemases, and/or class C cephalosporinases. Knowledge of the interactions of avibactam, a diazabicyclooctane with different β-lactamases, is required to anticipate future resistance threats. FOX family β-lactamases possess unique hydrolytic properties with a broadened substrate profile to include cephamycins, partly as a result of an isoleucine at position 346, instead of the conserved asparagine found in most AmpCs. Interestingly, a single amino acid substitution at N346 in theCitrobacterAmpC is implicated in resistance to the aztreonam-avibactam combination. In order to understand how diverse active-site topologies affect avibactam inhibition, we tested a panel of clinicalEnterobacteriaceaeisolates producingblaFOXusing ceftazidime-avibactam, determined the biochemical parameters for inhibition using the FOX-4 variant, and probed the atomic structure of avibactam with FOX-4. Avibactam restored susceptibility to ceftazidime for most isolates producingblaFOX; two isolates, one expressingblaFOX-4and the other producingblaFOX-5, displayed an MIC of 16 μg/ml for the combination. FOX-4 possessed ak2/Kvalue of 1,800 ± 100 M−1· s−1and an off rate (koff) of 0.0013 ± 0.0003 s−1. Mass spectrometry showed that the FOX-4–avibactam complex did not undergo chemical modification for 24 h. Analysis of the crystal structure of FOX-4 with avibactam at a 1.5-Å resolution revealed a unique characteristic of this AmpC β-lactamase. Unlike in thePseudomonas-derived cephalosporinase 1 (PDC-1)–avibactam crystal structure, interactions (e.g., hydrogen bonding) between avibactam and position I346 in FOX-4 are not evident. Furthermore, another residue is not observed to be close enough to compensate for the loss of these critical hydrogen-bonding interactions. This observation supports findings from the inhibition analysis of FOX-4; FOX-4 possessed the highestKd(dissociation constant) value (1,600 nM) for avibactam compared to other AmpCs (7 to 660 nM). Medicinal chemists must consider the properties of extended-spectrum AmpCs, such as the FOX β-lactamases, for the design of future diazabicyclooctanes.

scholarly journals Activity of NXL104 in Combination with β-Lactams against Genetically Characterized Escherichia coli and Klebsiella pneumoniae Isolates Producing Class A Extended-Spectrum β-Lactamases and Class C β-Lactamases

2011 ◽  
Vol 55 (5) ◽  
pp. 2434-2437 ◽  
Author(s):  
P. R. S. Lagacé-Wiens ◽  
F. Tailor ◽  
P. Simner ◽  
M. DeCorby ◽  
J. A. Karlowsky ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
The Novel ◽  
Content Type ◽  
E Coli ◽  
Class A ◽  
Extended Spectrum ◽  
Class C ◽  
Lactamase Inhibitor

ABSTRACTThe novel non-β-lactam β-lactamase inhibitor NXL104, in combination with cefepime, ceftazidime, ceftriaxone, amdinocillin, and meropenem, was tested against 190 extended-spectrum β-lactamase (ESBL)-producingEscherichia coliandKlebsiella pneumoniaeisolates, 94 AmpC-hyperproducingE. coliisolates, and 8 AmpC/ESBL-coexpressingE. coliisolates. NXL104 restored 100% susceptibility to the partner cephalosporins for all isolates tested. Amdinocillin and meropenem MICs were modestly improved (2 to 32 times lower) by NXL104. These results suggest that NXL104 may be useful in combination with β-lactams for the treatment of infections caused by ESBL- and AmpC-producingEnterobacteriaceae.

scholarly journals Antimicrobial Activity of Ceftazidime-Avibactam against Gram-Negative Organisms Collected from U.S. Medical Centers in 2012

2013 ◽  
Vol 58 (3) ◽  
pp. 1684-1692 ◽  
Author(s):  
Helio S. Sader ◽  
Mariana Castanheira ◽  
Robert K. Flamm ◽  
David J. Farrell ◽  
Ronald N. Jones
Keyword(s):  
The Novel ◽  
Gram Negative ◽  
Content Type ◽  
Class A ◽  
Medical Centers ◽  
Fixed Concentration ◽  
Clinically Significant ◽  
Gram Negative Organisms ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor

ABSTRACTThe activities of the novel β-lactam–β-lactamase inhibitor combination ceftazidime-avibactam and comparator agents were evaluated against a contemporary collection of clinically significant Gram-negative bacilli. Avibactam is a novel non-β-lactam β-lactamase inhibitor that inhibits Ambler class A, C, and some D enzymes. A total of 10,928 Gram-negative bacilli—8,640Enterobacteriaceae, 1,967Pseudomonas aeruginosa, and 321Acinetobactersp. isolates—were collected from 73 U.S. hospitals and tested for susceptibility by reference broth microdilution methods in a central monitoring laboratory (JMI Laboratories, North Liberty, IA, USA). Ceftazidime was combined with avibactam at a fixed concentration of 4 μg/ml. Overall, 99.8% ofEnterobacteriaceaestrains were inhibited at a ceftazidime-avibactam MIC of ≤4 μg/ml. Ceftazidime-avibactam was active against extended-spectrum β-lactamase (ESBL)-phenotypeEscherichia coliandKlebsiella pneumoniae, meropenem-nonsusceptible (MIC ≥ 2 μg/ml)K. pneumoniae, and ceftazidime-nonsusceptibleEnterobacter cloacae. Among ESBL-phenotypeK. pneumoniaestrains, 61.1% were meropenem susceptible and 99.3% were inhibited at a ceftazidime-avibactam MIC of ≤4 μg/ml. AmongP. aeruginosastrains, 96.9% were inhibited at a ceftazidime-avibactam MIC of ≤8 μg/ml, and susceptibility rates for meropenem, ceftazidime, and piperacillin-tazobactam were 82.0, 83.2, and 78.3%, respectively. Ceftazidime-avibactam was the most active compound tested against meropenem-nonsusceptibleP. aeruginosa(MIC50/MIC90, 4/16 μg/ml; 87.3% inhibited at ≤8 μg/ml).Acinetobacterspp. (ceftazidime-avibactam MIC50/MIC90, 16/>32 μg/ml) showed high rates of resistance to most tested agents. In summary, ceftazidime-avibactam demonstrated potent activity against a large collection of contemporary Gram-negative bacilli isolated from patients in U.S. hospitals in 2012, including organisms that are resistant to most currently available agents, such asK. pneumoniaecarbapenemase (KPC)-producingEnterobacteriaceaeand meropenem-nonsusceptibleP. aeruginosa.

scholarly journals Substrate Spectrum Extension of PenA in Burkholderia thailandensis with a Single Amino Acid Deletion, Glu168del

2012 ◽  
Vol 56 (7) ◽  
pp. 4005-4008 ◽  
Author(s):  
Hyojeong Yi ◽  
Karan Kim ◽  
Kwang-Hwi Cho ◽  
Oksung Jung ◽  
Heenam Stanley Kim
Keyword(s):  
Deletion Mutation ◽  
Single Amino Acid ◽  
Functional Domain ◽  
Amino Acid Deletion ◽  
Burkholderia Thailandensis ◽  
Content Type ◽  
Class A ◽  
Omega Loop ◽  
Substitution Mutations ◽  
Substrate Spectrum

ABSTRACTWe describe a deletion mutation in a class A β-lactamase, PenA, ofBurkholderia thailandensisthat extended the substrate spectrum of the enzyme to include ceftazidime. Glu168del was located in a functional domain called the omega loop causing expansion of the space in the loop, which in turn increased flexibility at the active site. This deletion mutation represents a rare but significant alternative mechanical path to substrate spectrum extension in PenA besides more common substitution mutations.

2,4,6-Trimethylpyridine-3,5-dicarbonitrile

2006 ◽  
Vol 62 (7) ◽  
pp. o2765-o2767
Author(s):  
Hong-Li Wang ◽  
Bin Zhang ◽  
Yi Dai
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Title Compound ◽  
Asymmetric Unit ◽  
Compound C ◽  
Hydrogen Bonding Interactions

The title compound, C10H9N3, is essently planar, except for the methyl H atoms. The asymmetric unit consists of two molecules. In the crystal structure, weak intramolecular C—H...N hydrogen-bonding interactions occur, linking the molecules into chains propagating along the a axis.

scholarly journals Cyclic Boronates Inhibit All Classes of β-Lactamases

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Samuel T. Cahill ◽  
Ricky Cain ◽  
David Y. Wang ◽  
Christopher T. Lohans ◽  
David W. Wareham ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Bacterial Infections ◽  
Binding Mode ◽  
Gram Negative ◽  
Content Type ◽  
Class A ◽  
Class D ◽  
Dual Action ◽  
The Common ◽  
Continued Use

ABSTRACT β-Lactamase-mediated resistance is a growing threat to the continued use of β-lactam antibiotics. The use of the β-lactam-based serine-β-lactamase (SBL) inhibitors clavulanic acid, sulbactam, and tazobactam and, more recently, the non-β-lactam inhibitor avibactam has extended the utility of β-lactams against bacterial infections demonstrating resistance via these enzymes. These molecules are, however, ineffective against the metallo-β-lactamases (MBLs), which catalyze their hydrolysis. To date, there are no clinically available metallo-β-lactamase inhibitors. Coproduction of MBLs and SBLs in resistant infections is thus of major clinical concern. The development of “dual-action” inhibitors, targeting both SBLs and MBLs, is of interest, but this is considered difficult to achieve due to the structural and mechanistic differences between the two enzyme classes. We recently reported evidence that cyclic boronates can inhibit both serine- and metallo-β-lactamases. Here we report that cyclic boronates are able to inhibit all four classes of β-lactamase, including the class A extended spectrum β-lactamase CTX-M-15, the class C enzyme AmpC from Pseudomonas aeruginosa, and class D OXA enzymes with carbapenem-hydrolyzing capabilities. We demonstrate that cyclic boronates can potentiate the use of β-lactams against Gram-negative clinical isolates expressing a variety of β-lactamases. Comparison of a crystal structure of a CTX-M-15:cyclic boronate complex with structures of cyclic boronates complexed with other β-lactamases reveals remarkable conservation of the small-molecule binding mode, supporting our proposal that these molecules work by mimicking the common tetrahedral anionic intermediate present in both serine- and metallo-β-lactamase catalysis.

scholarly journals Crystal structure of bis(μ2-4-tert-butyl-2-formylphenolato)-1:2κ3O1,O2:O1;3:4κ3O1,O2:O1-bis(4-tert-butyl-2-formylphenolato)-2κ2O1,O2;4κ2O1,O2-di-μ3-methoxido-1:2:3κ3O;1:3:4κ3O-di-μ2-methoxido-1:4κ2O;2:3κ2O-tetracopper(II)

2015 ◽  
Vol 71 (3) ◽  
pp. 324-326
Author(s):  
Bernhard Eberhard Christian Bugenhagen ◽  
Marc Heinrich Prosenc
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Coordination Sphere ◽  
Title Compound ◽  
Coordination Environment ◽  
Dinuclear Copper ◽  
Tert Butyl ◽  
Hydrogen Bonding Interactions ◽  
Square Planar

The structure of the title compound, [Cu4(CH3O)4(C11H13O2)4], consists of dimeric dinuclear copper(II) complexes oriented around a centre of inversion. Within each dinuclear fragment, the two CuIIatoms are in a distorted square-planar coordination sphere. Two neighbouring fragments are linked by four apical Cu—O contacts, yielding an overall square-pyramidal coordination environment for each of the four CuIIatoms. The molecules are arranged in layers parallel to (101). Non-classical C—H...O hydrogen-bonding interactions are observed between the layers.

Study on Novel Structure of Praseodymium Complex, C5H13O11Pr

2013 ◽  
Vol 834-836 ◽  
pp. 515-518
Author(s):  
Hai Xing Liu ◽  
Qing Liu ◽  
Ting Ting Huang ◽  
Yang Xu ◽  
Lin Tong Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Single Crystal ◽  
Hydrothermal Reaction ◽  
Crystal Packing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Novel Structure ◽  
Praseodymium Complex

A novel praseodymium complex C5H13O11Pr has been synthesized from hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Pr1 atom is nine coordinated by nine O atoms. The crystal packing is stabilized by O-H...O hydrogen bonding interactions.

scholarly journals Aqua(azido)[N-(pyridin-2-ylcarbonyl)pyridine-2-carboxamido-κ3N,N′,N′′]copper(II)

2013 ◽  
Vol 69 (11) ◽  
pp. m598-m599
Author(s):  
Sandra Bruda ◽  
Mark M. Turnbull ◽  
Jan L. Wikaira
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Water Molecule ◽  
Mean Deviation ◽  
Water Molecules ◽  
Air Oxidation ◽  
Apical Position ◽  
Complex Molecules ◽  
Hydrogen Bonding Interactions ◽  
Planar Array

The title compound, [Cu(C12H8N3O2)(N3)(H2O)], was formed by the air oxidation of 2-(aminomethyl)pyridine in 95% ethanol in the presence of copper(II) nitrate and sodium azide with condensation of the resulting picolinamide molecules to generate the imide moiety. The CuIIion has a square-pyramidal coordination sphere, the basal plane being occupied by four N atoms [two pyridine (py) N atoms, the imide N atom and an azide N atom] in a nearly planar array [mean deviation = 0.048 (6) Å] with the CuIIion displaced slightly from the plane [0.167 (5) Å] toward the fifth ligand. The apical position is occupied by a coordinating water molecule [Cu—O = 2.319 (4) Å]. The crystal structure is stabilized by hydrogen-bonding interactions between the water molecules and carbonyl O atoms. The inversion-related square-pyramidal complex molecules pack base-to-base with long Cu...Npycontact distances of 3.537 (9) Å, preventing coordination of a sixth ligand.

scholarly journals In VitroAntibacterial Activity of the Ceftazidime-Avibactam (NXL104) Combination against Pseudomonas aeruginosa Clinical Isolates

2012 ◽  
Vol 56 (3) ◽  
pp. 1606-1608 ◽  
Author(s):  
Premavathy Levasseur ◽  
Anne-Marie Girard ◽  
Monique Claudon ◽  
Herman Goossens ◽  
Michael T. Black ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Content Type ◽  
Reference Treatment ◽  
Common Reference ◽  
Class A ◽  
Potent Inhibition ◽  
Efficient Protection ◽  
Lactamase Inhibitor

ABSTRACTThe β-lactamase inhibitor avibactam (NXL104) displays potent inhibition of both class A and C enzymes. Thein vitroantibacterial activity of the combination ceftazidime-avibactam was evaluated against a clinical panel ofPseudomonas aeruginosaisolates. Avibactam offered efficient protection from hydrolysis since 94% of isolates were susceptible to ceftazidime when combined with 4 μg/ml avibactam, compared with 65% susceptible to ceftazidime alone. Ceftazidime-avibactam also demonstrated better antipseudomonal activity than imipenem (82% susceptibility), a common reference treatment.

Redetermination of trans-diaquabis(picolinato-κ2 N,O)cobalt(II) dihydrate

2006 ◽  
Vol 62 (4) ◽  
pp. m796-m798 ◽  
Author(s):  
Zerrin Heren ◽  
Cem Cüneyt Ersanlı ◽  
Cem Keser ◽  
Nazan Ocak Ískeleli
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Title Compound ◽  
Three Dimensional ◽  
Water Molecules ◽  
Inversion Center ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Distorted Octahedral

The crystal structure of the title compound, [Co(C6H4NO2)2(H2O)2]·2H2O, has been reinvestigated with improved precision [previous reports: Chang et al. (1972). J. Coord. Chem. 2, 31–34; Lumme et al. (1969). Suom. Kemistil. B, 42, 270]. In the title compound, the Co atom is located on an inversion center and its coordination can be described as slightly distorted octahedral, equatorially trans-coordinated by two N and O atoms of two picolinate ligands and axially coordinated by two O atoms of the water molecules. Intermolecular O—H...O and C—H...O hydrogen-bonding interactions result in the formation of an intricate three-dimensional network.

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