Extensively drug-resistant New Delhi metallo-β-lactamase-encoding bacteria in the environment, Dhaka, Bangladesh, 2012.
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ABSTRACT:
SUBMITTER: Toleman MA
PROVIDER: S-EPMC4451920 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Carbapenemase-producing Enterobacterales (CPE) bacteria are a critical global health concern; New Delhi metallo-β-lactamase (NDM) enzymes account for >25% of all CPE found in Switzerland. We characterized NDM-positive CPE submitted to the Swiss National Reference Center for Emerging Antibiotic Resistance during a 2-year period (January 2019-December 2020) phenotypically and by using whole-genome sequencing. Most isolates were either Klebsiella pneumoniae (59/141) or Escherichia coli (52/141), and >50% were obtained from screening swabs. Among the 108 sequenced isolates, NDM-1 was the most prevalent variant, occurring in 56 isolates, mostly K. pneumoniae (34/56); the next most prevalent was NDM-5, which occurred in 49 isolates, mostly E. coli (40/49). Fourteen isolates coproduced a second carbapenemase, predominantly an OXA-48-like enzyme, and almost one third of isolates produced a 16S rRNA methylase conferring panresistance to aminoglycosides. We identified successful plasmids and global lineages as major factors contributing to the increasing prevalence of NDMs in Switzerland.
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Project description:We characterized 9 New Delhi metallo-β-lactamase-producing Enterobacteriaceae (5 Klebsiella pneumoniae, 2 Escherichia coli, 1 Enterobacter cloacae, 1 Salmonella enterica serovar Senftenberg) isolates identified in the United States and cultured from 8 patients in 5 states during April 2009-March 2011. Isolates were resistant to β-lactams, fluoroquinolones, and aminoglycosides, demonstrated MICs ≤1 µg/mL of colistin and polymyxin, and yielded positive metallo-β-lactamase screening results. Eight isolates had blaNDM-1, and 1 isolate had a novel allele (blaNDM-6). All 8 patients had recently been in India or Pakistan, where 6 received inpatient health care. Plasmids carrying blaNDM frequently carried AmpC or extended spectrum β-lactamase genes. Two K. pneumoniae isolates and a K. pneumoniae isolate from Sweden shared incompatibility group A/C plasmids with indistinguishable restriction patterns and a common blaNDM fragment; all 3 were multilocus sequence type 14. Restriction profiles of the remaining New Delhi metallo-β-lactamase plasmids, including 2 from the same patient, were diverse.
| S-EPMC3713825 | biostudies-literature
Project description:Antibiotic resistance in bacterial pathogens poses a serious threat to human health and the metallo-β-lactamase (MBL) enzymes are responsible for much of this resistance. The recently identified New Delhi MBL 1 (NDM-1) is a novel member of this family that is capable of hydrolysing a wide variety of clinically important antibiotics. Here, the crystal structure of NDM-1 from Klebsiella pneumoniae is reported and its structure and active site are discussed in the context of other recently deposited coordinates of NDM-1.
| S-EPMC3212353 | biostudies-literature
Project description:Antimicrobial resistance (AMR) is a global public health crisis. Much of the burden of AMR in resource-limited settings remains unknown. This pilot study characterized clinical isolates of multidrug-resistant Gram-negative rods (MDR-GNRs) from Nicaragua. New Delhi metallo-β-lactamase (NDM) carbapenemase genes were detected in 60% of isolates. Enterobacteriaceae had the highest rates of NDM detection, with 92% (50/54 isolates) positive by polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) analysis revealed patterns of clustering among isolates by two factors: plasmid profiles and year of culture. These findings of very high rates of NDM-carbapenemase genes in MDR-GNRs from hospitals throughout Nicaragua are alarming. Further research is needed to determine clinical and epidemiologic factors associated with multidrug-resistant isolates and to guide interventions to limit further spread.
| S-EPMC7008350 | biostudies-literature
Project description:New Delhi metallo-β-lactamase (NDM) grants resistance to a broad spectrum of β-lactam antibiotics, including last-resort carbapenems, and is emerging as a global antibiotic resistance threat. Limited zinc availability adversely impacts the ability of NDM-1 to provide resistance, but a number of clinical variants have emerged that are more resistant to zinc scarcity (e.g., NDM-15). To provide a novel tool to better study metal ion sequestration in host-pathogen interactions, we describe the development of a fluorescent probe that reports on the dynamic metalation state of NDM within Escherichia coli. The thiol-containing probe selectively coordinates the dizinc metal cluster of NDM and results in a 17-fold increase in fluorescence intensity. Reversible binding enables competition and time-dependent studies that reveal fluorescence changes used to detect enzyme localization, substrate and inhibitor engagement, and changes to metalation state through the imaging of live E. coli using confocal microscopy. NDM-1 is shown to be susceptible to demetalation by intracellular and extracellular metal chelators in a live-cell model of zinc dyshomeostasis, whereas the NDM-15 metalation state is shown to be more resistant to zinc flux. The development of this reversible turn-on fluorescent probe for the metalation state of NDM provides a new tool for monitoring the impact of metal ion sequestration by host defense mechanisms and for detecting inhibitor-target engagement during the development of therapeutics to counter this resistance determinant.
| S-EPMC8230704 | biostudies-literature
Project description:Background and purposeBacteria producing New Delhi metallo-β-lactamase-1 (NDM-1) are an increasing clinical threat. NDM-1 can inactivate almost all β-lactams and is not sensitive to any existing β-lactamase inhibitors. To identify effective inhibitors of the NDM-1 enzyme and clarify the mechanism of action, a "lead compound" for developing more potent NDM-1 inhibitors needs to be provided.Experimental approachNatural compounds were tested by enzyme inhibition screening to find potential inhibitors. MIC assays, growth curve assays, and time-kill assays were conducted to evaluate the in vitro antibacterial activity of pterostilbene and the combination of pterostilbene and meropenem. A murine thigh model and a mouse pneumonia model were used to evaluate the in vivo efficacy of combined therapy. Molecular modelling and a mutational analysis were used to clarify the mechanism of action.Key resultsPterostilbene significantly inhibited NDM-1 hydrolysis activity in enzyme inhibition screening assays and effectively restored the effectiveness of meropenem in vitro with NDM-expressing isolates in antibacterial activity assays. In addition, the combined therapy effectively reduced the bacterial burden in a murine thigh model and protected mice from pneumonia caused by Klebsiella pneumoniae. By means of molecular dynamics simulation, we observed that pterostilbene localized to the catalytic pocket of NDM-1, hindering substrate binding to NDM-1 and reducing NDM-1 activity.Conclusions and implicationsThese findings indicated that pterostilbene combined with meropenem may offer a new safe and potential "lead compound" for the further development of NDM-1 inhibitors.
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Project description:New Delhi metallo-?-lactmase-1 (NDM-1) has recently attracted extensive attention for its biological activities to catalyze the hydrolysis of almost all of ?-lactam antibiotics. To study the catalytic property of NDM-1, the steady-kinetic parameters of NDM-1 toward several kinds of ?-lactam antibiotics have been detected. It could effectively hydrolyze most ?-lactams (k cat/K m ratios between 0.03 to 1.28 µmol?¹.s?¹), except aztreonam. We also found that thiophene-carboxylic acid derivatives could inhibit NDM-1 and have shown synergistic antibacterial activity in combination with meropenem. Flexible docking and quantum mechanics (QM) study revealed electrostatic interactions between the sulfur atom of thiophene-carboxylic acid derivatives and the zinc ion of NDM-1, along with hydrogen bond between inhibitor and His189 of NDM-1. The interaction models proposed here can be used in rational design of NDM-1 inhibitors.
| S-EPMC3652859 | biostudies-literature
Project description: Not available
| S-EPMC4806972 | biostudies-literature
Project description:The rise of antibiotic resistance calls for new therapeutics targeting resistance factors such as the New Delhi metallo-β-lactamase 1 (NDM-1), a bacterial enzyme that degrades β-lactam antibiotics. We present structure-guided computational methods for designing peptide macrocycles built from mixtures of l- and d-amino acids that are able to bind to and inhibit targets of therapeutic interest. Our methods explicitly consider the propensity of a peptide to favor a binding-competent conformation, which we found to predict rank order of experimentally observed IC50 values across seven designed NDM-1- inhibiting peptides. We were able to determine X-ray crystal structures of three of the designed inhibitors in complex with NDM-1, and in all three the conformation of the peptide is very close to the computationally designed model. In two of the three structures, the binding mode with NDM-1 is also very similar to the design model, while in the third, we observed an alternative binding mode likely arising from internal symmetry in the shape of the design combined with flexibility of the target. Although challenges remain in robustly predicting target backbone changes, binding mode, and the effects of mutations on binding affinity, our methods for designing ordered, binding-competent macrocycles should have broad applicability to a wide range of therapeutic targets.
| S-EPMC8000195 | biostudies-literature