Insights on the structural characteristics of NDM-1: The journey so far

Saini, Avneet; Bansal, Rohit

doi:10.4236/abc.2012.24040

Cited by 10 publications

(11 citation statements)

References 54 publications

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“…A great deal of enzymological data has been reported on NDM-1. 19 , 24 , 66 , 67 , 73 − 83 To date, structural studies on this enzyme have been limited to X-ray crystallography 66 , 67 and EXAFS spectroscopy. 19 Successful preparation of spectroscopically active, metal-substituted forms of NDM-1 has allowed us to perform more detailed structural studies, including the use of rapid-freeze-quench methods to examine the catalytic mechanism at the atomic level.…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic and Mechanistic Studies of Heterodimetallic Forms of Metallo-β-lactamase NDM-1

et al. 2014

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In an effort to characterize the roles of each metal ion in metallo-β-lactamase NDM-1, heterodimetallic analogues (CoCo-, ZnCo-, and CoCd-) of the enzyme were generated and characterized. UV–vis, 1H NMR, EPR, and EXAFS spectroscopies were used to confirm the fidelity of the metal substitutions, including the presence of a homogeneous, heterodimetallic cluster, with a single-atom bridge. This marks the first preparation of a metallo-β-lactamase selectively substituted with a paramagnetic metal ion, Co(II), either in the Zn1 (CoCd-NDM-1) or in the Zn2 site (ZnCo-NDM-1), as well as both (CoCo-NDM-1). We then used these metal-substituted forms of the enzyme to probe the reaction mechanism, using steady-state and stopped-flow kinetics, stopped-flow fluorescence, and rapid-freeze-quench EPR. Both metal sites show significant effects on the kinetic constants, and both paramagnetic variants (CoCd- and ZnCo-NDM-1) showed significant structural changes on reaction with substrate. These changes are discussed in terms of a minimal kinetic mechanism that incorporates all of the data.

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Section: Discussionmentioning

confidence: 99%

Spectroscopic and Mechanistic Studies of Heterodimetallic Forms of Metallo-β-lactamase NDM-1

et al. 2014

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“…The production of β-lactamase enzymes is the most common mechanism of bacterial resistance [1]. Carbapenemases are β-lactamases that have the ability to hydrolyse all β-lactam antibiotics, including carbapenem [2].…”

Section: Introductionmentioning

confidence: 99%

Comparison of in-house and commercial real time-PCR based carbapenemase gene detection methods in Enterobacteriaceae and non-fermenting gram-negative bacterial isolates

Smiljanic

Kaase

Ahmad-Nejad

et al. 2017

Ann Clin Microbiol Antimicrob

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BackgroundCarbapenemase-producing gram-negative bacteria are increasing globally and have been associated with outbreaks in hospital settings. Thus, the accurate detection of these bacteria in infections is mandatory for administering the adequate therapy and infection control measures. This study aimed to establish and evaluate a multiplex real-time PCR assay for the simultaneous detection of carbapenemase gene variants in gram-negative rods and to compare the performance with a commercial RT-PCR assay (Check-Direct CPE).Methods116 carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii isolates were genotyped for carbapenemase genes by PCR and sequencing. The defined isolates were used for the validation of the in-house RT-PCR by use of designed primer pairs and probes.ResultsAmong the carbapenem-resistant isolates the genes bla KPC, bla VIM, bla NDM or bla OXA were detected. Both RT-PCR assays detected all bla KPC, bla VIM and bla NDM in the isolates. The in-house RT-PCR detected 53 of 67 (79.0%) whereas the commercial assay detected only 29 (43.3%) of the OXA genes. The in-house sufficiently distinguished the most prevalent OXA types (23-like and 48-like) in the melting curve analysis and direct detection of the genes from positive blood culture vials.ConclusionThe Check-Direct CPE and the in-house RT-PCR assay detected the carbapenem resistance from solid culture isolates. Moreover, the in-house assay enabled the identification of carbapenemase genes directly from positive blood-culture vials. However, we observed insufficient detection of various OXA genes in both assays. Nevertheless, the in-house RT-PCR detected the majority of the OXA type genes in Enterobacteriaceae and A. baumannii.

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“…2). In addition, NDM is most closely related to VIM than to IMP with a sequence identity of 32.4% (Saini 2012). Hence, the closer amino acid sequence homology of VIM to NDM rather than its closer evolutionary distance to IMP might in part explain the observation in which VIM-positive isolates had greater mean MIC fold changes than IMP- positiveones (Fig.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Potentiation of Carbapenems with Tannic Acid Against Carbapenemase Producing Enterobacteriaceae: Exploring Natural Products as Potential Carbapenemase Inhibitors

Somboro

Sekyere

Amoako

et al. 2018

Preprint

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Resistance to antibiotics is increasing worldwide, necessitating urgent action to sustain the efficacy of existing antibiotics in clinical use. We show that tannic acid (TA) in combination with carbapenems can reduce and/or reverse the minimum inhibitory concentrations (MICs) of carbapenems to susceptible values in Enterobacteriaceae that express class A and B carbapenemases. MICs of carbapenems in the presence and absence of TA and other efflux pump inhibitors, TA-carbapenemases inhibition assays and computational studies were undertaken to determine the effect of TA on carbapenem susceptibility in Enterobacteriaceae. TA had the greatest effect on metallo-β-lactamases (MBLs) followed by class A serine-β-lactamases (SBLs). Antibiotic susceptibility testing showed that TA reversed the MICs of MBLs to susceptible values whilst substantially reducing the MICs of SBLs (class A). Tolerable cytotoxicity effect was observed for the concentrations tested. TA inhibited enzymes with a marked difference between ≈50% inhibition (IC50) for NDM-1 and KPC-2. Computational studies including molecular docking, molecular dynamics simulations and binding free energy calculations showed that TA interact with both MBLs and SBLs hydrophobic sites. Moreover, TA had a stronger binding affinity for MBLs than SBLs as the MBLs, specifically VIM-1 and NDM-1, interact with a larger number of their catalytic active-site residues than that of OXA- 48 and KPC-2. These in vitro evaluations together with computational simulation explain the potentiating effect of TA toward carbapenems against carbapenem-resistance enterobacteriaceae. This study proposes TA as a promising adjuvant for MBLs and SBLs.

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Insights on the structural characteristics of NDM-1: The journey so far

Cited by 10 publications

References 54 publications

Spectroscopic and Mechanistic Studies of Heterodimetallic Forms of Metallo-β-lactamase NDM-1

Spectroscopic and Mechanistic Studies of Heterodimetallic Forms of Metallo-β-lactamase NDM-1

Comparison of in-house and commercial real time-PCR based carbapenemase gene detection methods in Enterobacteriaceae and non-fermenting gram-negative bacterial isolates

In Vitro Potentiation of Carbapenems with Tannic Acid Against Carbapenemase Producing Enterobacteriaceae: Exploring Natural Products as Potential Carbapenemase Inhibitors

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