New Delhi metallo-b-lactamase-1(NDM-1)is capable of hydrolyzing nearly allβ-lactam antibiotics,posing an emerging threat to public health.There are currently less effective treatment options for treating NDM-1 positi...New Delhi metallo-b-lactamase-1(NDM-1)is capable of hydrolyzing nearly allβ-lactam antibiotics,posing an emerging threat to public health.There are currently less effective treatment options for treating NDM-1 positive"superbug",and no promising NDM-1 inhibitors were used in clinical practice.In this study,structure eactivity relationship based on thiosemicarbazone derivatives wassystematically characterized and their potential activities combined with meropenem(MEM)were evaluated.Compounds 19 bg and 19 bh exhibited excellent activity against 10 NDM-positive isolate clinical isolates in reversing MEM resistance.Further studies demonstrated compounds 19 bg and 19 bh were uncompetitive NDM-1 inhibitors with Ki Z 0.63 and 0.44 mmol/L,respectively.Molecular docking speculated that compounds 19 bg and 19 bh were most likely to bind in the allosteric pocket which would affect the catalytic effect of NDM-1 on the substrate meropenem.Toxicity evaluation experiment showed that no hemolysis activities even at concentrations of 1000 mg/m L against red blood cells.In vivo experimental results showed combination of MEM and compound 19 bh was markedly effective in treating infections caused by NDM-1 positive strain and prolonging the survival time of sepsis mice.Our finding showed that compound 19 bh might be a promising lead in developing new inhibitor to treat NDM-1 producing superbug.展开更多
New Delhi metallo-b-lactmase-1(NDM-1) catalyzes the hydrolysis of b-lactam antibiotics and cleaves the b-lactam ring of the molecule, conferring bacterial resistance against these medicines. In an effort to discover...New Delhi metallo-b-lactmase-1(NDM-1) catalyzes the hydrolysis of b-lactam antibiotics and cleaves the b-lactam ring of the molecule, conferring bacterial resistance against these medicines. In an effort to discover novel agents to treat this superbug, an old drug methisazone was found to be a weak NDM-1 inhibitor, with an IC50 of 297.6 mmol/L. Based on this result, a series of isatin-β-thiosemicarbazones(IBTs)were synthesized and biologically evaluated as novel NDM-1 inhibitors. Nine of the IBT compounds showed IC50 values of 〈10 mmol/L, the best of which was 2.72 mmol/L. Comparative field analysis(Co MFA) contour maps were generated to depict the structural features and molecular docking was performed to understand the possible binding mode of these inhibitors. The present research hereby has provided valuable information for further discovery of NDM-1 inhibitors.展开更多
To investigate the distribution of the genes of two major metallo-β-1actamases (MBL;i.e.,IMP and VIM) and class 1 integrons (intI) in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates...To investigate the distribution of the genes of two major metallo-β-1actamases (MBL;i.e.,IMP and VIM) and class 1 integrons (intI) in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates, from a university hospital in Sichuan between December 2004 and April 2005 were screened for MBL genes by PCR using primers specific for blaIMP-1, blaVIM and blaVIM-2 genes. The MBL-positive isolates were further assessed for class 1 integrons by PCRusing specific primers. The nucleotide sequences of several PCR products were also determined. The results revealed that the blaVIM gene was found in 81.5% (53/65) of all isolates, blaVIM-2 gene was found in only 1 isolate and the intl gene was observed in 45.3% (24/53) of blaVIM-positive isolates. One isolate carried simultaneously both blaIMP-1 and intl genes, and to the best of our knowledge this is the first report of such isolate in southwest China. These observations highlight that the genes for VIM β-1actamase and class 1 integrons were predominantly present among the imipenem-resistant P. aeruginosa tested, confirming the current widespread threat of imipenem-resistant, integron-borne P.aeruginosa.展开更多
New Delhi metallo-β-lactamase (NDM-1) has created a medical storm ever since it was first reported;as it is active on virtually all clinically used β-lactam antibiotics. NDM-1 rampancy worldwide is now considered a ...New Delhi metallo-β-lactamase (NDM-1) has created a medical storm ever since it was first reported;as it is active on virtually all clinically used β-lactam antibiotics. NDM-1 rampancy worldwide is now considered a nightmare scenario, particularly due to its rapid dissemination. An underlying theme in the majority of recent studies is structural characterization as knowledge of the three-dimensional structure of NDM-1 shall help find connections between its structure and function. Moreover, structural details are even critical in order to reveal the resistance mecha- nism to β-lactam antibiotics. In this perspective, we review structural characteristics of NDM-1 that have been delineated since its first report. We anticipate that these structure-function connections made by its characterization shall further serve as future guidelines for elucidating pathways towards de novo design of functional inhibitors.展开更多
Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1(NDM-1)are a type of newly discovered antibioticresistant bacteria.The rapid pandemic spread of NDM-1 bacteri...Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1(NDM-1)are a type of newly discovered antibioticresistant bacteria.The rapid pandemic spread of NDM-1 bacteria worldwide(spreading to India,Pakistan,Europe,America,and Chinese Taiwan)in less than 2 months characterizes these microbes as a potentially major global health problem.The drug resistance of NDM-1 bacteria is largely due to plasmids containing the blaNDM-1 gene shuttling through bacterial populations.The NDM-1 enzyme encoded by the blaNDM-1 gene hydrolyzes β-lactam antibiotics,allowing the bacteria to escape the action of antibiotics.Although the biological functions and structural features of NDM-1 have been proposed according to results from functional and structural investigation of its homologues,the precise molecular characteristics and mechanism of action of NDM-1 have not been clarified.Here,we report the threedimensional structure of NDM-1 with two catalytic zinc ions in its active site.Biological and mass spectroscopy results revealed that D-captopril can effectively inhibit the enzymatic activity of NDM-1 by binding to its active site with high binding affinity.The unique features concerning the primary sequence and structural conformation of the active site distinguish NDM-1 from other reported metallo-β-lactamases(MBLs)and implicate its role in wide spectrum drug resistance.We also discuss the molecular mechanism of NDM-1 action and its essential role in the pandemic of drug-resistant NDM-1 bacteria.Our results will provide helpful information for future drug discovery targeting drug resistance caused by NDM-1 and related metallo-β-lactamases.展开更多
NDM-1(New Delhi metallo-beta-lactamase)gene encodes a metallo-beta-lactamase(MBL)with high carbapenemase activity,which makes the host bacterial strain easily dispatch the last-resort antibiotics known as carbapenems ...NDM-1(New Delhi metallo-beta-lactamase)gene encodes a metallo-beta-lactamase(MBL)with high carbapenemase activity,which makes the host bacterial strain easily dispatch the last-resort antibiotics known as carbapenems and cause global concern.Here we present the bioinformatics data showing an unexpected similarity between NDM-1 and beta-lactamase II from Erythrobacter litoralis,a marine microbial isolate.We have further expressed these two mature proteins in E.coli cells,both of which present as a monomer with a molecular mass of 25 kDa.Antimicrobial susceptibility assay reveals that they share similar substrate specificities and are sensitive to aztreonam and tigecycline.The conformational change accompanied with the zinc binding visualized by nuclear magnetic resonance,Zn2+-bound NDM-1,adopts at least some stable tertiary structure in contrast to the metal-free protein.Our work implies a close evolutionary relationship between antibiotic resistance genes in environmental reservoir and in the clinic,challenging the antimicrobial resistance monitoring.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.81903447 for Bing Zhao,81903623 for Yongfang Yao,81703328 for Liying Ma,and 81430085 for Hongmin Liu)National Key Research and Development Project of China(Nos.2016YFA0501800 and 2018YFE0195100 for Hongmin Liu)
文摘New Delhi metallo-b-lactamase-1(NDM-1)is capable of hydrolyzing nearly allβ-lactam antibiotics,posing an emerging threat to public health.There are currently less effective treatment options for treating NDM-1 positive"superbug",and no promising NDM-1 inhibitors were used in clinical practice.In this study,structure eactivity relationship based on thiosemicarbazone derivatives wassystematically characterized and their potential activities combined with meropenem(MEM)were evaluated.Compounds 19 bg and 19 bh exhibited excellent activity against 10 NDM-positive isolate clinical isolates in reversing MEM resistance.Further studies demonstrated compounds 19 bg and 19 bh were uncompetitive NDM-1 inhibitors with Ki Z 0.63 and 0.44 mmol/L,respectively.Molecular docking speculated that compounds 19 bg and 19 bh were most likely to bind in the allosteric pocket which would affect the catalytic effect of NDM-1 on the substrate meropenem.Toxicity evaluation experiment showed that no hemolysis activities even at concentrations of 1000 mg/m L against red blood cells.In vivo experimental results showed combination of MEM and compound 19 bh was markedly effective in treating infections caused by NDM-1 positive strain and prolonging the survival time of sepsis mice.Our finding showed that compound 19 bh might be a promising lead in developing new inhibitor to treat NDM-1 producing superbug.
基金supported by the “111” Project of Ministry of Education of China (No. B06005)the National Natural Science Foundation of China (No. 21672114)the National Basic Research Program of China (No. 2013CB734004)
文摘New Delhi metallo-b-lactmase-1(NDM-1) catalyzes the hydrolysis of b-lactam antibiotics and cleaves the b-lactam ring of the molecule, conferring bacterial resistance against these medicines. In an effort to discover novel agents to treat this superbug, an old drug methisazone was found to be a weak NDM-1 inhibitor, with an IC50 of 297.6 mmol/L. Based on this result, a series of isatin-β-thiosemicarbazones(IBTs)were synthesized and biologically evaluated as novel NDM-1 inhibitors. Nine of the IBT compounds showed IC50 values of 〈10 mmol/L, the best of which was 2.72 mmol/L. Comparative field analysis(Co MFA) contour maps were generated to depict the structural features and molecular docking was performed to understand the possible binding mode of these inhibitors. The present research hereby has provided valuable information for further discovery of NDM-1 inhibitors.
基金a grant from National Natu-ral Science Foundation of China (No. 30370079)
文摘To investigate the distribution of the genes of two major metallo-β-1actamases (MBL;i.e.,IMP and VIM) and class 1 integrons (intI) in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates, from a university hospital in Sichuan between December 2004 and April 2005 were screened for MBL genes by PCR using primers specific for blaIMP-1, blaVIM and blaVIM-2 genes. The MBL-positive isolates were further assessed for class 1 integrons by PCRusing specific primers. The nucleotide sequences of several PCR products were also determined. The results revealed that the blaVIM gene was found in 81.5% (53/65) of all isolates, blaVIM-2 gene was found in only 1 isolate and the intl gene was observed in 45.3% (24/53) of blaVIM-positive isolates. One isolate carried simultaneously both blaIMP-1 and intl genes, and to the best of our knowledge this is the first report of such isolate in southwest China. These observations highlight that the genes for VIM β-1actamase and class 1 integrons were predominantly present among the imipenem-resistant P. aeruginosa tested, confirming the current widespread threat of imipenem-resistant, integron-borne P.aeruginosa.
文摘New Delhi metallo-β-lactamase (NDM-1) has created a medical storm ever since it was first reported;as it is active on virtually all clinically used β-lactam antibiotics. NDM-1 rampancy worldwide is now considered a nightmare scenario, particularly due to its rapid dissemination. An underlying theme in the majority of recent studies is structural characterization as knowledge of the three-dimensional structure of NDM-1 shall help find connections between its structure and function. Moreover, structural details are even critical in order to reveal the resistance mecha- nism to β-lactam antibiotics. In this perspective, we review structural characteristics of NDM-1 that have been delineated since its first report. We anticipate that these structure-function connections made by its characterization shall further serve as future guidelines for elucidating pathways towards de novo design of functional inhibitors.
基金Natural Sciences Foundation of China(NSFC,Grant No.81872913)the CAMS Initiative for Innovative Medicine(Grant No.2016-I2M-1-013)+1 种基金the Fundamental Research Funds for Central Public-interest Scientific Institution(Centre for Tuberculosis)(Grant No.2016ZX310183-3)the National High-tech R&D Program(863 Program,Grant No.2015AA020911)
基金supported by the National Natural Science Foundation of China(Grant Nos.30870486 and 30730022)the National Major Projects(Grant Nos.2009ZX10004-804,2009ZX09311-001 and 2009ZX10004-304)the National Basic Research Program(973 Program)(Grant Nos.2011CB915501 and 2011CB910304).
文摘Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1(NDM-1)are a type of newly discovered antibioticresistant bacteria.The rapid pandemic spread of NDM-1 bacteria worldwide(spreading to India,Pakistan,Europe,America,and Chinese Taiwan)in less than 2 months characterizes these microbes as a potentially major global health problem.The drug resistance of NDM-1 bacteria is largely due to plasmids containing the blaNDM-1 gene shuttling through bacterial populations.The NDM-1 enzyme encoded by the blaNDM-1 gene hydrolyzes β-lactam antibiotics,allowing the bacteria to escape the action of antibiotics.Although the biological functions and structural features of NDM-1 have been proposed according to results from functional and structural investigation of its homologues,the precise molecular characteristics and mechanism of action of NDM-1 have not been clarified.Here,we report the threedimensional structure of NDM-1 with two catalytic zinc ions in its active site.Biological and mass spectroscopy results revealed that D-captopril can effectively inhibit the enzymatic activity of NDM-1 by binding to its active site with high binding affinity.The unique features concerning the primary sequence and structural conformation of the active site distinguish NDM-1 from other reported metallo-β-lactamases(MBLs)and implicate its role in wide spectrum drug resistance.We also discuss the molecular mechanism of NDM-1 action and its essential role in the pandemic of drug-resistant NDM-1 bacteria.Our results will provide helpful information for future drug discovery targeting drug resistance caused by NDM-1 and related metallo-β-lactamases.
基金the Innovative Research Group of the National Natural Science Foundation of China(Grant No.81021003)Work in GFG's laboratory is supported,in part,by the National Basic Research Program(973 Project)from China Ministry of Science and Technology(Grant No.2011CB504703)。
文摘NDM-1(New Delhi metallo-beta-lactamase)gene encodes a metallo-beta-lactamase(MBL)with high carbapenemase activity,which makes the host bacterial strain easily dispatch the last-resort antibiotics known as carbapenems and cause global concern.Here we present the bioinformatics data showing an unexpected similarity between NDM-1 and beta-lactamase II from Erythrobacter litoralis,a marine microbial isolate.We have further expressed these two mature proteins in E.coli cells,both of which present as a monomer with a molecular mass of 25 kDa.Antimicrobial susceptibility assay reveals that they share similar substrate specificities and are sensitive to aztreonam and tigecycline.The conformational change accompanied with the zinc binding visualized by nuclear magnetic resonance,Zn2+-bound NDM-1,adopts at least some stable tertiary structure in contrast to the metal-free protein.Our work implies a close evolutionary relationship between antibiotic resistance genes in environmental reservoir and in the clinic,challenging the antimicrobial resistance monitoring.