1
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Stewart NK, Toth M, Quan P, Buynak JD, Smith CA, Vakulenko SB. Restricted Rotational Flexibility of the C5α-Methyl-Substituted Carbapenem NA-1-157 Leads to Potent Inhibition of the GES-5 Carbapenemase. ACS Infect Dis 2024; 10:1232-1249. [PMID: 38511828 PMCID: PMC11160566 DOI: 10.1021/acsinfecdis.3c00683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Carbapenem antibiotics are used as a last-resort treatment for infections caused by multidrug-resistant bacteria. The wide spread of carbapenemases in Gram-negative bacteria has severely compromised the utility of these drugs and represents a serious public health threat. To combat carbapenemase-mediated resistance, new antimicrobials and inhibitors of these enzymes are urgently needed. Here, we describe the interaction of the atypically C5α-methyl-substituted carbapenem, NA-1-157, with the GES-5 carbapenemase. MICs of this compound against Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii producing the enzyme were reduced 4-16-fold when compared to MICs of the commercial carbapenems, reaching clinically sensitive breakpoints. When NA-1-157 was combined with meropenem, a strong synergistic effect was observed. Kinetic and ESI-LC/MS studies demonstrated that NA-1-157 is a potent inhibitor of GES-5, with a high inactivation efficiency of (2.9 ± 0.9) × 105 M-1 s-1. Acylation of GES-5 by NA-1-157 was biphasic, with the fast phase completing within seconds, and the slow phase taking several hours and likely proceeding through a reversible tetrahedral intermediate. Deacylation was extremely slow (k3 = (2.4 ± 0.3) × 10-7 s-1), resulting in a residence time of 48 ± 6 days. MD simulation of the GES-5-meropenem and GES-5-NA-1-157 acyl-enzyme complexes revealed that the C5α-methyl group in NA-1-157 sterically restricts rotation of the 6α-hydroxyethyl group preventing ingress of the deacylating water into the vicinity of the scissile bond of the acyl-enzyme intermediate. These data demonstrate that NA-1-157 is a potent irreversible inhibitor of the GES-5 carbapenemase.
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Affiliation(s)
- Nichole K. Stewart
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Marta Toth
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Pojun Quan
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275, USA
| | - John D. Buynak
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275, USA
| | - Clyde A. Smith
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, CA 94025, USA
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Sergei B. Vakulenko
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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2
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Parwana D, Gu J, Chen S, Bethel CR, Marshall E, Hujer AM, Bonomo RA, Haider S. The Structural Role of N170 in Substrate-Assisted Deacylation in KPC-2 β-Lactamase. Angew Chem Int Ed Engl 2024; 63:e202317315. [PMID: 38227422 DOI: 10.1002/anie.202317315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/16/2024] [Accepted: 01/16/2024] [Indexed: 01/17/2024]
Abstract
The amino acid substitutions in Klebsiella pneumoniae carbapenemase 2 (KPC-2) that have arisen in the clinic are observed to lead to the development of resistance to ceftazidime-avibactam, a preferred treatment for KPC bearing Gram-negative bacteria. Specific substitutions in the omega loop (R164-D179) result in changes in the structure and function of the enzyme, leading to alterations in substrate specificity, decreased stability, and more recently observed, increased resistance to ceftazidime/avibactam. Using accelerated rare-event sampling well-tempered metadynamics simulations, we explored in detail the structural role of R164 and D179 variants that are described to confer ceftazidime/avibactam resistance. The buried conformation of D179 substitutions produce a pronounced structural disorder in the omega loop - more than R164 mutants, where the crystallographic omega loop structure remains mostly intact. Our findings also reveal that the conformation of N170 plays an underappreciated role impacting drug binding and restricting deacylation. The results further support the hypothesis that KPC-2 D179 variants employ substrate-assisted catalysis for ceftazidime hydrolysis, involving the ring amine of the aminothiazole group to promote deacylation and catalytic turnover. Moreover, the shift in the WT conformation of N170 contributes to reduced deacylation and an altered spectrum of enzymatic activity.
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Affiliation(s)
| | - Jing Gu
- UCL School of Pharmacy, London, UK
| | | | - Christopher R Bethel
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA
| | - Emma Marshall
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA
| | - Andrea M Hujer
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Robert A Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Clinician Scientist Investigator, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA
- Department of Molecular Biology and Microbiology, Pharmacology, Biochemistry, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
| | - Shozeb Haider
- UCL School of Pharmacy, London, UK
- UCL Centre for Advanced Research Computing, London, UK
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3
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Barlow M, Tenover FC. Phylogenetic predictions of carbapenemase activity from the Guiana extended-spectrum (GES) family of β-lactamases. JAC Antimicrob Resist 2024; 6:dlad150. [PMID: 38213313 PMCID: PMC10783257 DOI: 10.1093/jacamr/dlad150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 11/27/2023] [Indexed: 01/13/2024] Open
Abstract
Objectives We investigated the amino acid substitutions in the GES family of ESBLs that were most likely to be involved in the evolution of carbapenemase activity. Methods To identify the substitutions that are functionally important, we analysed the evolutionary history of the GES β-lactamases using an alignment and phylogeny to identify sites in GES that show evidence of positive selection and the selected phenotypes. Results and Conclusions Data indicate that the substitutions G170S and G243A are associated with carbapenemase activity. The substitutions Q43E, E104K and T237A are most likely associated with ESBL activity.
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Affiliation(s)
- Miriam Barlow
- Department of Molecular and Cell Biology, University of California, Merced, CA 95343, USA
| | - Fred C Tenover
- College of Arts and Sciences: Biology, University of Dayton, Dayton, OH 45469, USA
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4
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Cartagena AJ, Taylor KL, Smith JT, Manson AL, Pierce VM, Earl AM, Bhattacharyya RP. The carbapenem inoculum effect provides insight into the molecular mechanisms underlying carbapenem resistance in Enterobacterales. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.23.541813. [PMID: 37292717 PMCID: PMC10245868 DOI: 10.1101/2023.05.23.541813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Carbapenem-resistant Enterobacterales (CRE) are important pathogens that can develop resistance via multiple molecular mechanisms, including hydrolysis or reduced antibiotic influx. Identifying these mechanisms can improve pathogen surveillance, infection control, and patient care. We investigated how resistance mechanisms influence the carbapenem inoculum effect (IE), a phenomenon where inoculum size affects antimicrobial susceptibility testing (AST). We demonstrated that seven different carbapenemases impart a meropenem IE in Escherichia coli. Across 110 clinical CRE isolates, the carbapenem IE strictly depended on resistance mechanism: all carbapenemase-producing CRE (CP-CRE) exhibited a strong IE, whereas porin-deficient CRE displayed none. Concerningly, 50% and 24% of CP-CRE isolates changed susceptibility classification to meropenem and ertapenem, respectively, across the allowable inoculum range in clinical guidelines. The meropenem IE, and the ratio of ertapenem to meropenem minimal inhibitory concentration (MIC) at standard inoculum, reliably identified CP-CRE. Understanding how resistance mechanisms affect AST could improve diagnosis and guide therapies for CRE infections.
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Affiliation(s)
| | - Kyra L. Taylor
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Joshua T. Smith
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Abigail L. Manson
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Virginia M. Pierce
- Microbiology Laboratory, Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology and Clinical Laboratories, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ashlee M. Earl
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Roby P. Bhattacharyya
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Infectious Diseases Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
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5
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Mataseje LF, Pitout J, Croxen M, Mulvey MR, Dingle TC. Three separate acquisitions of bla NDM-1 in three different bacterial species from a single patient. Eur J Clin Microbiol Infect Dis 2023; 42:1275-1280. [PMID: 37688673 PMCID: PMC10511597 DOI: 10.1007/s10096-023-04651-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/07/2023] [Indexed: 09/11/2023]
Abstract
To investigate the acquisition and relatedness of New Delhi Metallo-beta-lactamase among multiple separate species from one patient. Five isolates from three species (Pseudomonas aeruginosa; Pa, Acinetobacter baumannii; Ab and Proteus mirabilis; Pm) suspected of harbouring a carbapenemase were investigated by phenotype (antimicrobial susceptibilities) and whole genome sequencing. Epidemiological data was collected on this patient. Three different carbapenemase genes were detected; blaVIM-1 (Pa; ST773), blaOXA-23 (Ab, ST499) and blaNDM-1 identified in all isolates. NDM regions were found chromosomally integrated in all isolates. Data showed no evidence of NDM-1 transfer within this patient suggesting the enzyme was acquired in three separate events.
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Affiliation(s)
- L F Mataseje
- National Microbiology laboratory, Winnipeg, MB, Canada
| | - J Pitout
- Alberta Precision Laboratories, Public Health Laboratory, 3030 Hospital Drive N.W, Calgary, AB, T2N 4W4, Canada
- University of Calgary, Calgary, AB, Canada
- University of Pretoria, Pretoria, Gauteng, South Africa
| | - M Croxen
- Alberta Precision Laboratories, Public Health Laboratory, 3030 Hospital Drive N.W, Calgary, AB, T2N 4W4, Canada
- University of Alberta, Edmonton, AB, Canada
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB, Canada
- Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - M R Mulvey
- National Microbiology laboratory, Winnipeg, MB, Canada
| | - T C Dingle
- Alberta Precision Laboratories, Public Health Laboratory, 3030 Hospital Drive N.W, Calgary, AB, T2N 4W4, Canada.
- University of Calgary, Calgary, AB, Canada.
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6
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Smith CA, Stewart NK, Toth M, Quan P, Buynak JD, Vakulenko SB. The C5α-Methyl-Substituted Carbapenem NA-1-157 Exhibits Potent Activity against Klebsiella spp. Isolates Producing OXA-48-Type Carbapenemases. ACS Infect Dis 2023; 9:1123-1136. [PMID: 37130087 PMCID: PMC10722881 DOI: 10.1021/acsinfecdis.3c00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The wide spread of carbapenem-hydrolyzing β-lactamases in Gram-negative bacteria has diminished the utility of the last-resort carbapenem antibiotics, significantly narrowing the available therapeutic options. In the Enterobacteriaceae family, which includes many important clinical pathogens such as Klebsiella pneumoniae and Escherichia coli, production of class D β-lactamases from the OXA-48-type family constitutes the major mechanism of resistance to carbapenems. To address the public health threat posed by these enzymes, novel, effective therapeutics are urgently needed. Here, we report evaluation of a novel, C5α-methyl-substituted carbapenem, NA-1-157, and show that its MICs against bacteria producing OXA-48-type enzymes were reduced by 4- to 32-fold when compared to meropenem. When combined with commercial carbapenems, the potency of NA-1-157 was further enhanced, resulting in target potentiation concentrations ranging from 0.125 to 2 μg/mL. Kinetic studies demonstrated that the compound is poorly hydrolyzed by OXA-48, with a catalytic efficiency 30- to 50-fold lower than those of imipenem and meropenem. Acylation of OXA-48 by NA-1-157 was severely impaired, with a rate 10,000- to 36,000-fold slower when compared to the commercial carbapenems. Docking, molecular dynamics, and structural studies demonstrated that the presence of the C5α-methyl group in NA-1-157 creates steric clashes within the active site, leading to differences in the position and the hydrogen-bonding pattern of the compound, which are incompatible with efficient acylation. This study demonstrates that NA-1-157 is a promising novel carbapenem for treatment of infections caused by OXA-48-producing bacterial pathogens.
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Affiliation(s)
- Clyde A Smith
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California 94025, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Nichole K Stewart
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Marta Toth
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Pojun Quan
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - John D Buynak
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Sergei B Vakulenko
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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7
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Comito M, Monguzzi R, Tagliapietra S, Maspero A, Palmisano G, Cravotto G. From Batch to the Semi-Continuous Flow Hydrogenation of pNB, pNZ-Protected Meropenem. Pharmaceutics 2023; 15:pharmaceutics15051322. [PMID: 37242564 DOI: 10.3390/pharmaceutics15051322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/07/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
Meropenem is currently the most common carbapenem in clinical applications. Industrially, the final synthetic step is characterized by a heterogeneous catalytic hydrogenation in batch mode with hydrogen and Pd/C. The required high-quality standard is very difficult to meet and specific conditions are required to remove both protecting groups [i.e., p-nitrobenzyl (pNB) and p-nitrobenzyloxycarbonyl (pNZ)] simultaneously. The three-phase gas-liquid-solid system makes this step difficult and unsafe. The introduction of new technologies for small-molecule synthesis in recent years has opened up new landscapes in process chemistry. In this context, we have investigated meropenem hydrogenolysis using microwave (MW)-assisted flow chemistry for use as a new technology with industrial prospects. The reaction parameters (catalyst amount, T, P, residence time, flow rate) in the move from the batch process to semi-continuous flow were investigated under mild conditions to determine their influence on the reaction rate. The optimization of the residence time (840 s) and the number of cycles (4) allowed us to develop a novel protocol that halves the reaction time compared to batch production (14 min vs. 30 min) while maintaining the same product quality. The increase in productivity using this semi-continuous flow technique compensates for the slightly lower yield (70% vs. 74%) obtained in batch mode.
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Affiliation(s)
- Marziale Comito
- Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
- Research and Development, ACS Dobfar SpA, Via Paullo 9, 20067 Tribiano, Italy
| | - Riccardo Monguzzi
- Research and Development, ACS Dobfar SpA, Via Paullo 9, 20067 Tribiano, Italy
| | - Silvia Tagliapietra
- Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
| | - Angelo Maspero
- Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Via Valleggio 9, 22100 Como, Italy
| | - Giovanni Palmisano
- Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Via Valleggio 9, 22100 Como, Italy
| | - Giancarlo Cravotto
- Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
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8
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Asempa TE, Kois AK, Gill CM, Nicolau DP. Phenotypes, genotypes and breakpoints: an assessment of β-lactam/β-lactamase inhibitor combinations against OXA-48. J Antimicrob Chemother 2023; 78:636-645. [PMID: 36626311 DOI: 10.1093/jac/dkac425] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 09/21/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Two of the three recently approved β-lactam agent (BL)/β-lactamase inhibitor (BLI) combinations have higher CLSI susceptibility breakpoints (ceftazidime/avibactam 8 mg/L; meropenem/vaborbactam 4 mg/L) compared with the BL alone (ceftazidime 4 mg/L; meropenem 1 mg/L). This can lead to a therapeutic grey area on susceptibility reports depending on resistance mechanism. For instance, a meropenem-resistant OXA-48 isolate (MIC 4 mg/L) may appear as meropenem/vaborbactam-susceptible (MIC 4 mg/L) despite vaborbactam's lack of OXA-48 inhibitory activity. METHODS OXA-48-positive (n = 51) and OXA-48-negative (KPC, n = 5; Klebsiella pneumoniae wild-type, n = 1) Enterobacterales were utilized. Susceptibility tests (broth microdilution) were conducted with ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam, as well as their respective BL partner. Antimicrobial activity of all six agents was evaluated in the murine neutropenic thigh model using clinically relevant exposures. Efficacy was assessed as the change in bacterial growth at 24 h, compared with 0 h controls. RESULTS On average, the three BL/BLI agents resulted in robust bacteria killing among OXA-48-negative isolates. Among OXA-48-positive isolates, poor in vivo activity with imipenem/relebactam was concordant with its resistant phenotypic profile. Variable meropenem/vaborbactam activity was observed among isolates with a 'susceptible' MIC of 4 mg/L. Only 30% (7/23) of isolates at meropenem/vaborbactam MICs of 2 and 4 mg/L met the ≥1-log bacterial reduction threshold predictive of clinical efficacy in serious infections. In contrast, ceftazidime/avibactam resulted in marked bacterial density reduction across the range of MICs, and 96% (49/51) of isolates exceeded the ≥1-log bacterial reduction threshold. CONCLUSIONS Data demonstrate that current imipenem/relebactam and ceftazidime/avibactam CLSI breakpoints are appropriate. Data also suggest that higher meropenem/vaborbactam breakpoints relative to meropenem can translate to potentially poor clinical outcomes in patients infected with OXA-48-harbouring isolates.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Abigail K Kois
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Christian M Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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9
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Asempa TE, Kois AK, Gill CM, Nicolau DP. Phenotypes, genotypes and breakpoints: an assessment of β-lactam/ β-lactamase inhibitor combinations against OXA-48. J Antimicrob Chemother 2022; 77:2622-2631. [PMID: 35325165 DOI: 10.1093/jac/dkac074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/10/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Two out of the three recently approved β-lactam (BL)/β-lactamase inhibitors (BLIs) have higher CLSI susceptibility breakpoints (ceftazidime/avibactam 8 mg/L; meropenem/vaborbactam 4 mg/L) compared with the BL alone (ceftazidime 4 mg/L; meropenem 1 mg/L). This can lead to a therapeutic grey area on susceptibility reports depending on resistance mechanism. For instance, a meropenem-resistant OXA-48 isolate (MIC 4 mg/L) may appear as meropenem/vaborbactam-susceptible (MIC 4 mg/L) despite vaborbactam's lack of OXA-48 inhibitory activity. METHODS OXA-48-positive (n = 51) and OXA-48-negative (KPC, n = 5; Klebsiella pneumoniae WT, n = 1) Enterobacterales were utilized. Susceptibility tests (broth microdilution) were conducted with ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam, as well as their respective BL partner. Antimicrobial activity of all six agents was evaluated in the murine neutropenic thigh model using clinically relevant exposures. Efficacy was assessed as the change in bacterial growth at 24 h, compared with 0 h controls. RESULTS On average, the three BL/BLI agents resulted in robust bacteria killing among OXA-48-negative isolates. Among OXA-48-positive isolates, poor in vivo activity with imipenem/relebactam was concordant with its resistant phenotypic profile. Variable meropenem/vaborbactam activity was observed among isolates with a 'susceptible' MIC of 4 mg/L. Only 30% (7/23) of isolates at meropenem/vaborbactam MICs of 2 and 4 mg/L met the ≥1 log bacterial reduction threshold predictive of clinical efficacy in serious infections. In contrast, ceftazidime/avibactam resulted in marked bacterial density reduction across the range of MICs and 73% (37/51) of isolates exceeded the ≥1 log bacterial reduction threshold. CONCLUSIONS Data demonstrate that current imipenem/relebactam and ceftazidime/avibactam CLSI breakpoints are appropriate. Data also suggest that higher meropenem/vaborbactam breakpoints relative to meropenem can translate to potentially poor clinical outcomes in patients infected with OXA-48-harbouring isolates.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Abigail K Kois
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Christian M Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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10
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Carbapenem Combinations for Infections Caused by Carbapenemase-Producing Pseudomonas aeruginosa: Experimental In Vitro and In Vivo Analysis. Antibiotics (Basel) 2022; 11:antibiotics11091212. [PMID: 36139991 PMCID: PMC9495166 DOI: 10.3390/antibiotics11091212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/04/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
In the context of difficult-to-treat carbapenem-resistant Pseudomonas aeruginosa infections, we evaluated imipenem, meropenem, and doripenem combinations against eleven carbapenemase-producing P. aeruginosa isolates. According to the widespread global distribution of high-risk clones and carbapenemases, four representative isolates were selected: ST175 (OXA-2/VIM-20), ST175 (VIM-2), ST235 (GES-5), and ST111 (IMP-33), for efficacy studies using a sepsis murine model. Minimum inhibitory concentration (mg/L) ranges were 64–256 for imipenem and 16–128 for meropenem and doripenem. In vitro, imipenem plus meropenem was synergistic against 72% of isolates and doripenem plus meropenem or imipenem against 55% and 45%, respectively. All combinations were synergistic against the ST175, ST235, and ST155 clones. In vivo, meropenem diminished the spleen and blood bacterial concentrations of four and three isolates, respectively, with better efficacy than imipenem or doripenem. The combinations did not show efficacy compared with the more active monotherapies, except for imipenem plus meropenem, which reduced the ST235 bacterial spleen concentration. Mortality decreased with imipenem plus meropenem or doripenem for the ST175 isolate. Results suggest that carbapenem combinations are not an alternative for severe infections by carbapenemase-producing P. aeruginosa. Meropenem monotherapy showed in vivo efficacy despite its high MIC, probably because its dosage allowed a sufficient antimicrobial exposure at the infection sites.
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11
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Chudyk EI, Beer M, Limb MAL, Jones CA, Spencer J, van der Kamp MW, Mulholland AJ. QM/MM Simulations Reveal the Determinants of Carbapenemase Activity in Class A β-Lactamases. ACS Infect Dis 2022; 8:1521-1532. [PMID: 35877936 PMCID: PMC9379904 DOI: 10.1021/acsinfecdis.2c00152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Indexed: 11/28/2022]
Abstract
β-lactam antibiotic resistance in Gram-negative bacteria, primarily caused by β-lactamase enzymes that hydrolyze the β-lactam ring, has become a serious clinical problem. Carbapenems were formerly considered "last resort" antibiotics because they escaped breakdown by most β-lactamases, due to slow deacylation of the acyl-enzyme intermediate. However, an increasing number of Gram-negative bacteria now produce β-lactamases with carbapenemase activity: these efficiently hydrolyze the carbapenem β-lactam ring, severely limiting the treatment of some bacterial infections. Here, we use quantum mechanics/molecular mechanics (QM/MM) simulations of the deacylation reactions of acyl-enzyme complexes of eight β-lactamases of class A (the most widely distributed β-lactamase group) with the carbapenem meropenem to investigate differences between those inhibited by carbapenems (TEM-1, SHV-1, BlaC, and CTX-M-16) and those that hydrolyze them (SFC-1, KPC-2, NMC-A, and SME-1). QM/MM molecular dynamics simulations confirm the two enzyme groups to differ in the preferred acyl-enzyme orientation: carbapenem-inhibited enzymes favor hydrogen bonding of the carbapenem hydroxyethyl group to deacylating water (DW). QM/MM simulations of deacylation give activation free energies in good agreement with experimental hydrolysis rates, correctly distinguishing carbapenemases. For the carbapenem-inhibited enzymes, free energies for deacylation are significantly higher than for the carbapenemases, even when the hydroxyethyl group was restrained to prevent interaction with the DW. Analysis of these simulations, and additional simulations of mutant enzymes, shows how factors including the hydroxyethyl orientation, the active site volume, and architecture (conformations of Asn170 and Asn132; organization of the oxyanion hole; and the Cys69-Cys238 disulfide bond) collectively determine catalytic efficiency toward carbapenems.
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Affiliation(s)
- Ewa I. Chudyk
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Michael Beer
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
- School
of Cellular and Molecular Medicine, University
of Bristol Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Michael A. L. Limb
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Charlotte A. Jones
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - James Spencer
- School
of Cellular and Molecular Medicine, University
of Bristol Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Marc W. van der Kamp
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
- School
of Biochemistry, University of Bristol Medical
Sciences Building, University Walk, Bristol BS8 1TD, United
Kingdom
| | - Adrian J. Mulholland
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
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12
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Imipenem/Relebactam Resistance in Clinical Isolates of Extensively Drug Resistant Pseudomonas aeruginosa: Inhibitor-Resistant β-Lactamases and Their Increasing Importance. Antimicrob Agents Chemother 2022; 66:e0179021. [PMID: 35435707 DOI: 10.1128/aac.01790-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multidrug-resistant (MDR) Pseudomonas aeruginosa infections are a major clinical challenge. Many isolates are carbapenem resistant, which severely limits treatment options; thus, novel therapeutic combinations, such as imipenem-relebactam (IMI/REL), ceftazidime-avibactam (CAZ/AVI), ceftolozane-tazobactam (TOL/TAZO), and meropenem-vaborbactam (MEM/VAB) were developed. Here, we studied two extensively drug-resistant (XDR) P. aeruginosa isolates, collected in the United States and Mexico, that demonstrated resistance to IMI/REL. Whole-genome sequencing (WGS) showed that both isolates contained acquired GES β-lactamases, intrinsic PDC and OXA β-lactamases, and disruptions in the genes encoding the OprD porin, thereby inhibiting uptake of carbapenems. In one isolate (ST17), the entire C terminus of OprD deviated from the expected amino acid sequence after amino acid G388. In the other (ST309), the entire oprD gene was interrupted by an ISPa1328 insertion element after amino acid D43, rendering this porin nonfunctional. The poor inhibition by REL of the GES β-lactamases (GES-2, -19, and -20; apparent Ki of 19 ± 2 μM, 23 ± 2 μM, and 21 ± 2 μM, respectively) within the isolates also contributed to the observed IMI/REL-resistant phenotype. Modeling of REL binding to the active site of GES-20 suggested that the acylated REL is positioned in an unstable conformation as a result of a constrained Ω-loop.
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13
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Teixeira P, Pinto N, Henriques I, Tacão M. KPC-3-, GES-5-, and VIM-1-Producing Enterobacterales Isolated from Urban Ponds. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19105848. [PMID: 35627386 PMCID: PMC9141432 DOI: 10.3390/ijerph19105848] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/05/2022] [Accepted: 05/07/2022] [Indexed: 01/27/2023]
Abstract
Carbapenems are antibiotics of pivotal importance in human medicine, the efficacy of which is threatened by the increasing prevalence of carbapenem-resistant Enterobacterales (CRE). Urban ponds may be reservoirs of CRE, although this hypothesis has been poorly explored. We assessed the proportion of CRE in urban ponds over a one-year period and retrieved 23 isolates. These were submitted to BOX-PCR, PFGE, 16S rDNA sequencing, antibiotic susceptibility tests, detection of carbapenemase-encoding genes, and conjugation assays. Isolates were affiliated with Klebsiella (n = 1), Raoultella (n = 11), Citrobacter (n = 8), and Enterobacter (n = 3). Carbapenemase-encoding genes were detected in 21 isolates: blaKPC (n = 20), blaGES-5 (n = 6), and blaVIM (n = 1), with 7 isolates carrying two carbapenemase genes. Clonal isolates were collected from different ponds and in different campaigns. Citrobacter F6, Raoultella N9, and Enterobacter N10 were predicted as pathogens from whole-genome sequence analysis, which also revealed the presence of several resistance genes and mobile genetic elements. We found that blaKPC-3 was located on Tn4401b (Citrobacter F6 and Enterobacter N10) or Tn4401d (Raoultella N9). The former was part of an IncFIA-FII pBK30683-like plasmid. In addition, blaGES-5 was in a class 3 integron, either chromosomal (Raoultella N9) or plasmidic (Enterobacter N10). Our findings confirmed the role of urban ponds as reservoirs and dispersal sites for CRE.
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Affiliation(s)
- Pedro Teixeira
- CESAM (Centre for Marine and Environmental Studies), University of Aveiro, 3810-193 Aveiro, Portugal; (P.T.); (M.T.)
- Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Nuno Pinto
- Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Isabel Henriques
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, 3004-531 Coimbra, Portugal
- Correspondence:
| | - Marta Tacão
- CESAM (Centre for Marine and Environmental Studies), University of Aveiro, 3810-193 Aveiro, Portugal; (P.T.); (M.T.)
- Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal;
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14
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C6 Hydroxymethyl-Substituted Carbapenem MA-1-206 Inhibits the Major Acinetobacter baumannii Carbapenemase OXA-23 by Impeding Deacylation. mBio 2022; 13:e0036722. [PMID: 35420470 PMCID: PMC9239083 DOI: 10.1128/mbio.00367-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Acinetobacter baumannii has become a major nosocomial pathogen, as it is often multidrug-resistant, which results in infections characterized by high mortality rates. The bacterium achieves high levels of resistance to β-lactam antibiotics by producing β-lactamases, enzymes which destroy these valuable agents. Historically, the carbapenem family of β-lactam antibiotics have been the drugs of choice for treating A. baumannii infections. However, their effectiveness has been significantly diminished due to the pathogen’s production of carbapenem-hydrolyzing class D β-lactamases (CHDLs); thus, new antibiotics and inhibitors of these enzymes are urgently needed. Here, we describe a new carbapenem antibiotic, MA-1-206, in which the canonical C6 hydroxyethyl group has been replaced with hydroxymethyl. The antimicrobial susceptibility studies presented here demonstrated that this compound is more potent than meropenem and imipenem against A. baumannii producing OXA-23, the most prevalent CHDL of this pathogen, and also against strains producing the CHDL OXA-24/40 and the class B metallo-β-lactamase VIM-2. Our kinetic and mass spectrometry studies revealed that this drug is a reversible inhibitor of OXA-23, where inhibition takes place through a branched pathway. X-ray crystallographic studies, molecular docking, and molecular dynamics simulations of the OXA-23-MA-1-206 complex show that the C6 hydroxymethyl group forms a hydrogen bond with the carboxylated catalytic lysine of OXA-23, effectively preventing deacylation. These results provide a promising strategy for designing a new generation of CHDL-resistant carbapenems to restore their efficacy against deadly A. baumannii infections.
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15
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Ayoub Moubareck C, Hammoudi Halat D. The Collateral Effects of COVID-19 Pandemic on the Status of Carbapenemase-Producing Pathogens. Front Cell Infect Microbiol 2022; 12:823626. [PMID: 35372126 PMCID: PMC8968076 DOI: 10.3389/fcimb.2022.823626] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 01/27/2022] [Indexed: 12/28/2022] Open
Abstract
The serious challenge of antimicrobial resistance continues to threaten public health and lingers in the era of the coronavirus disease 2019 (COVID-19), declared pandemic by the World Health Organization. While the pandemic has triggered the importance of infection control practices and preventive measures such as physical distancing, hand hygiene, travel reduction and quarantine, the ongoing alarm of antimicrobial resistance seems to accompany the pandemic too. Antimicrobial resistance has been fostered during COVID-19, possibly due to high rate of empirical antibiotic utilization in COVID-19 patients, increased use of biocides, and the disruption of proper healthcare for other conditions. Specifically, carbapenemase-producing Gram-negative bacteria have shown to cause secondary bacterial infections in patients hospitalized for COVID-19. Clinical and microbiological evidence of such infections is accumulating in different parts of the world. With the resilient nature of carbapenemases, their association with mortality, and the limited treatment options available, concerns regarding this group of antibiotic-hydrolyzing enzymes during the pandemic are expected to upsurge. While the additional burden carbapenemases exert on healthcare is worrisome, it remains hidden or abandoned among the various health consequences of the pandemic. The purpose of this minireview is to shed a light on carbapenemase-associated infections during such unprecedented time of COVID-19. A focused insight shall be made into carbapenemases, their implications for COVID-19 patients, and the features and consequences of co-infection, with a review of available evidence from pertinent literature. The importance of increased surveillance for carbapenemase-producers and optimizing their management in relation to the pandemic, shall be addressed as well.
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Affiliation(s)
- Carole Ayoub Moubareck
- College of Natural and Health Sciences, Zayed University, Dubai, United Arab Emirates
- *Correspondence: Carole Ayoub Moubareck,
| | - Dalal Hammoudi Halat
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Bekaa, Lebanon
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16
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Mustafa M, Winum JY. The importance of sulfur-containing motifs in drug design and discovery. Expert Opin Drug Discov 2022; 17:501-512. [PMID: 35193437 DOI: 10.1080/17460441.2022.2044783] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Sulfur-containing functional groups are privileged motifs that occur in various pharmacologically effective substances and several natural products. Various functionalities are found with a sulfur atom at diverse oxidation states, as illustrated by thioether, sulfoxide, sulfone, sulfonamide, sulfamate, and sulfamide functions. They are valuable scaffolds in the field of medicinal chemistry and are part of a large array of approved drugs and clinical candidates. AREA COVERED Herein, the authors review the current research on the development of organosulfur-based drug discovery. This article also covers details of their roles in the new lead compounds reported in the literature over the past five years 2017-2021. EXPERT OPINION Given its prominent role in medicinal chemistry and its importance in drug discovery, sulfur has attracted continuing interest and has been used in the design of various valuable compounds that demonstrate a variety of biological and pharmacological feature activities. Overall, sulfur's role in medicinal chemistry continues to grow. However, many sulfur functionalities remain underused in small-molecule drug discovery and deserve special attention in the armamentarium for treating diverse diseases. Research efforts are also still required for the development of a synthetic methodology for direct access to these functions and late-stage functionalization.
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Affiliation(s)
- Muhamad Mustafa
- IBMM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.,Department of Medicinal Chemistry, Faculty of Pharmacy, Deraya Unuversity, Minia, Egypt
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17
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Kemp MT, Nichols DA, Zhang X, Defrees K, Na I, Renslo AR, Chen Y. Mutation of the conserved Asp-Asp pair impairs the structure, function, and inhibition of CTX-M Class A β-lactamase. FEBS Lett 2021; 595:2981-2994. [PMID: 34704263 DOI: 10.1002/1873-3468.14215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/07/2021] [Accepted: 10/21/2021] [Indexed: 11/07/2022]
Abstract
The Asp233-Asp246 pair is highly conserved in Class A β-lactamases, which hydrolyze β-lactam antibiotics. Here, we characterize its function using CTX-M-14 β-lactamase. The D233N mutant displayed decreased activity that is substrate-dependent, with reductions in kcat /Km ranging from 20% for nitrocefin to 6-fold for cefotaxime. In comparison, the mutation reduced the binding of a known reversible inhibitor by 10-fold. The mutant structures showed movement of the 213-219 loop and the loss of the Thr216-Thr235 hydrogen bond, which was restored by inhibitor binding. Mutagenesis of Thr216 further highlighted its contribution to CTX-M activity. These results demonstrate the importance of the aspartate pair to CTX-M hydrolysis of substrates with bulky side chains, while suggesting increased protein flexibility as a means to evolve drug resistance.
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Affiliation(s)
- M Trent Kemp
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Derek A Nichols
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Xiujun Zhang
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Kyle Defrees
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA
| | - Insung Na
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Adam R Renslo
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
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18
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Mushtaq S, Meunier D, Vickers A, Woodford N, Livermore DM. Activity of imipenem/relebactam against Pseudomonas aeruginosa producing ESBLs and carbapenemases. J Antimicrob Chemother 2021; 76:434-442. [PMID: 33152755 DOI: 10.1093/jac/dkaa456] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/05/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND ESBL- and carbapenemase-producing Pseudomonas aeruginosa are prevalent in, for example, the Middle East, Eastern Europe and Latin America, though rarer elsewhere. Because P. aeruginosa readily mutate to become carbapenem resistant via loss of OprD, isolates producing ESBLs are often as broadly resistant as those producing carbapenemases. We hypothesized that: (i) relebactam might overcome class A carbapenemases directly in P. aeruginosa; and (ii) relebactam's inhibition of AmpC, which gives a generalized potentiation of imipenem against the species, might restore imipenem susceptibility in OprD-deficient ESBL producers. METHODS MICs were determined using CLSI agar dilution for P. aeruginosa isolates producing ESBLs, principally VEB types, and for those producing GES-5, KPC and other carbapenemases. RESULTS Relebactam potentiated imipenem by around 4-8-fold for most P. aeruginosa isolates producing VEB and other ESBLs; however, MICs were typically only reduced to 4-16 mg/L, thus mostly remaining above EUCAST's susceptible range and only partly overlapping CLSI's intermediate range. Strong (approx. 64-fold) potentiation was seen for isolates producing KPC carbapenemases, but only 2-fold synergy for those with GES-5. Predictably, potentiation was not seen for isolates with class B or D carbapenemase activity. CONCLUSIONS Relebactam did potentiate imipenem against ESBL-producing P. aeruginosa, which are mostly imipenem resistant via OprD loss, but this potentiation was generally insufficient to reduce imipenem MICs to the clinical range. Imipenem resistance owing to KPC carbapenemases was reversed by relebactam in P. aeruginosa, just as for Enterobacterales.
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Affiliation(s)
- Shazad Mushtaq
- Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Danièle Meunier
- Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Anna Vickers
- Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Neil Woodford
- Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - David M Livermore
- Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK.,Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, UK
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19
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Laboratory Variants GES G170L, GES G170K, and GES G170H Increase Carbapenem Hydrolysis and Confer Resistance to Clavulanic Acid. Antimicrob Agents Chemother 2021; 65:AAC.01931-20. [PMID: 33722888 DOI: 10.1128/aac.01931-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 03/05/2021] [Indexed: 01/20/2023] Open
Abstract
The Guiana extended-spectrum (GES) β-lactamase GESG170H, GESG170L, and GESG170K mutants showed k cat, Km , and k cat/Km values very dissimilar to those of GES-1 and GES-5. The enhancement of the hydrolytic activity against carbapenems is potentially due to a shift of the substrate in the active site that provides better positioning of the deacylating water molecule caused by the presence of the imidazole ring of H170 and of the long side chain of K170 and L170.
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20
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Stewart NK, Toth M, Stasyuk A, Lee M, Smith CA, Vakulenko SB. Inhibition of the Clostridioides difficile Class D β-Lactamase CDD-1 by Avibactam. ACS Infect Dis 2021; 7:1164-1176. [PMID: 33390002 PMCID: PMC8826747 DOI: 10.1021/acsinfecdis.0c00714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Avibactam is a potent diazobicyclooctane inhibitor of class A and C β-lactamases. The inhibitor also exhibits variable activity against some class D enzymes from Gram-negative bacteria; however, its interaction with recently discovered class D β-lactamases from Gram-positive bacteria has not been studied. Here, we describe microbiological, kinetic, and mass spectrometry studies of the interaction of avibactam with CDD-1, a class D β-lactamase from the clinically important pathogen Clostridioides difficile, and show that avibactam is a potent irreversible mechanism-based inhibitor of the enzyme. X-ray crystallographic studies at three time-points demonstrate the rapid formation of a stable CDD-1-avibactam acyl-enzyme complex and highlight differences in the anchoring of the inhibitor by class D enzymes from Gram-positive and Gram-negative bacteria.
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Affiliation(s)
- Nichole K Stewart
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Marta Toth
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Anastasiya Stasyuk
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California 94025, United States
| | - Mijoon Lee
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Clyde A Smith
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California 94025, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Sergei B Vakulenko
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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21
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Ellington MJ, Davies F, Jauneikaite E, Hopkins KL, Turton JF, Adams G, Pavlu J, Innes AJ, Eades C, Brannigan ET, Findlay J, White L, Bolt F, Kadhani T, Chow Y, Patel B, Mookerjee S, Otter JA, Sriskandan S, Woodford N, Holmes A. A Multispecies Cluster of GES-5 Carbapenemase-Producing Enterobacterales Linked by a Geographically Disseminated Plasmid. Clin Infect Dis 2021; 71:2553-2560. [PMID: 31746994 PMCID: PMC7744980 DOI: 10.1093/cid/ciz1130] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/18/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Early and accurate treatment of infections due to carbapenem-resistant organisms is facilitated by rapid diagnostics, but rare resistance mechanisms can compromise detection. One year after a Guiana Extended-Spectrum (GES)-5 carbapenemase-positive Klebsiella oxytoca infection was identified by whole-genome sequencing (WGS; later found to be part of a cluster of 3 cases), a cluster of 11 patients with GES-5-positive K. oxytoca was identified over 18 weeks in the same hospital. METHODS Bacteria were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, antimicrobial susceptibility testing followed European Committee on Antimicrobial Susceptibility Testing guidelines. Ertapenem-resistant isolates were referred to Public Health England for characterization using polymerase chain reaction (PCR) detection of GES, pulsed-field gel electrophoresis (PFGE), and WGS for the second cluster. RESULTS The identification of the first GES-5 K. oxytoca isolate was delayed, being identified by WGS. Implementation of a GES-gene PCR informed the occurrence of the second cluster in real time. In contrast to PFGE, WGS phylogenetic analysis refuted an epidemiological link between the 2 clusters; it also suggested a cascade of patient-to-patient transmission in the later cluster. A novel GES-5-encoding plasmid was present in K. oxytoca, Escherichia coli, and Enterobacter cloacae isolates from unlinked patients within the same hospital group and in human and wastewater isolates from 3 hospitals elsewhere in the United Kingdom. CONCLUSIONS Genomic sequencing revolutionized the epidemiological understanding of the clusters; it also underlined the risk of covert plasmid propagation in healthcare settings and revealed the national distribution of the resistance-encoding plasmid. Sequencing results also informed and led to the ongoing use of enhanced diagnostic tests for detecting carbapenemases locally and nationally.
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Affiliation(s)
- Matthew J Ellington
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom.,Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, National Infections Service, Public Health England, London, United Kingdom
| | - Frances Davies
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Elita Jauneikaite
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom.,Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Katie L Hopkins
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom.,Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, National Infections Service, Public Health England, London, United Kingdom
| | - Jane F Turton
- Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, National Infections Service, Public Health England, London, United Kingdom
| | - George Adams
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Jiri Pavlu
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Andrew J Innes
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Christopher Eades
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Eimear T Brannigan
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Jacqueline Findlay
- Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, National Infections Service, Public Health England, London, United Kingdom
| | - Leila White
- Microbiology, Royal Preston Hospital, Lancashire Teaching Hospitals National Health Service Foundation Trust, Preston, United Kingdom
| | - Frances Bolt
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Tokozani Kadhani
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Yimmy Chow
- North West London Health Protection Team, Public Health England, London, United Kingdom
| | - Bharat Patel
- Public Health Laboratory London, National Infections Service, Public Health England, London, United Kingdom
| | - Siddharth Mookerjee
- Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Jonathan A Otter
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom.,Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Shiranee Sriskandan
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Neil Woodford
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom.,Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, National Infections Service, Public Health England, London, United Kingdom
| | - Alison Holmes
- National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom.,Imperial College Healthcare National Health Service Trust, London, United Kingdom
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22
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Mehta SC, Furey IM, Pemberton OA, Boragine DM, Chen Y, Palzkill T. KPC-2 β-lactamase enables carbapenem antibiotic resistance through fast deacylation of the covalent intermediate. J Biol Chem 2021; 296:100155. [PMID: 33273017 PMCID: PMC7895804 DOI: 10.1074/jbc.ra120.015050] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 01/23/2023] Open
Abstract
Serine active-site β-lactamases hydrolyze β-lactam antibiotics through the formation of a covalent acyl-enzyme intermediate followed by deacylation via an activated water molecule. Carbapenem antibiotics are poorly hydrolyzed by most β-lactamases owing to slow hydrolysis of the acyl-enzyme intermediate. However, the emergence of the KPC-2 carbapenemase has resulted in widespread resistance to these drugs, suggesting it operates more efficiently. Here, we investigated the unusual features of KPC-2 that enable this resistance. We show that KPC-2 has a 20,000-fold increased deacylation rate compared with the common TEM-1 β-lactamase. Furthermore, kinetic analysis of active site alanine mutants indicates that carbapenem hydrolysis is a concerted effort involving multiple residues. Substitution of Asn170 greatly decreases the deacylation rate, but this residue is conserved in both KPC-2 and non-carbapenemase β-lactamases, suggesting it promotes carbapenem hydrolysis only in the context of KPC-2. X-ray structure determination of the N170A enzyme in complex with hydrolyzed imipenem suggests Asn170 may prevent the inactivation of the deacylating water by the 6α-hydroxyethyl substituent of carbapenems. In addition, the Thr235 residue, which interacts with the C3 carboxylate of carbapenems, also contributes strongly to the deacylation reaction. In contrast, mutation of the Arg220 and Thr237 residues decreases the acylation rate and, paradoxically, improves binding affinity for carbapenems. Thus, the role of these residues may be ground state destabilization of the enzyme-substrate complex or, alternatively, to ensure proper alignment of the substrate with key catalytic residues to facilitate acylation. These findings suggest modifications of the carbapenem scaffold to avoid hydrolysis by KPC-2 β-lactamase.
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Affiliation(s)
- Shrenik C Mehta
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Ian M Furey
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Orville A Pemberton
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - David M Boragine
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Timothy Palzkill
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA.
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First Detection of GES-5-Producing Escherichia coli from Livestock-An Increasing Diversity of Carbapenemases Recognized from German Pig Production. Microorganisms 2020; 8:microorganisms8101593. [PMID: 33081194 PMCID: PMC7602714 DOI: 10.3390/microorganisms8101593] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 12/13/2022] Open
Abstract
Resistance to carbapenems due to carbapenemase-producing Enterobacteriaceae (CPE) is an increasing threat to human health worldwide. In recent years, CPE could be found only sporadically from livestock, but concern rose that livestock might become a reservoir for CPE. In 2019, the first GES carbapenemase-producing Escherichia coli from livestock was detected within the German national monitoring on antimicrobial resistance. The isolate was obtained from pig feces and was phenotypically resistant to meropenem and ertapenem. The isolate harbored three successive blaGES genes encoding for GES-1, GES-5 and GES-5B in an incomplete class-I integron on a 12 kb plasmid (pEC19-AB02908; Acc. No. MT955355). The strain further encoded for virulence-associated genes typical for uropathogenic E. coli, which might hint at an increased pathogenic potential. The isolate produced the third carbapenemase detected from German livestock. The finding underlines the importance CPE monitoring and detailed characterization of new isolates.
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Spread of Klebsiella pneumoniae ST45 Producing GES-5 Carbapenemase or GES-1 Extended-Spectrum β-Lactamase in Newborns and Infants. Antimicrob Agents Chemother 2020; 64:AAC.00595-20. [PMID: 32631822 DOI: 10.1128/aac.00595-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Al-Zahrani IA, Al-Ahmadi BM. Dissemination of VIM-producing Pseudomonas aeruginosa associated with high-risk clone ST654 in a tertiary and quaternary hospital in Makkah, Saudi Arabia. J Chemother 2020; 33:12-20. [PMID: 32602782 DOI: 10.1080/1120009x.2020.1785741] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
To the best of our knowledge, no molecular surveillance that has been conducted to identify the most common clones of carbapenem-resistant Pseudomonas aeruginosa (CRPA) in western Saudi Arabia. Therefore, this study aimed to identify genetic diversity and the most common CRPA clones in this region. Thirty-five CRPA isolates were collected from a tertiary and quaternary hospital in Makkah. bla VIM was the most common carbapenemase-encoding gene (11 CRPA isolates), while blaGES was reported in only three isolates. CRPA isolates were subjected to multi- locus sequence typing and showed relatively high genetic diversity with 20 sequence types. Approximately one-third (31.4%) of the CRPA isolates belonged to two high-risk clones (ST235 and ST654). This troublesome finding raises serious concerns about the emergence and further dissemination of CRPA high-risk clones in local hospitals and suggest that surveillance programs should be established in this region to monitor and control clonal dissemination of all multidrug resistant bacteria, including CRPA.
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Affiliation(s)
- Ibrahim A Al-Zahrani
- Faculty of Applied Medical Sciences, Medical Laboratory Technology Department, King Abdulaziz University, Jeddah, Saudi Arabia.,Special infectious Agents Unit-Biosafety Level-3, King Fahad Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Bashaer M Al-Ahmadi
- Faculty of Applied Medical Sciences, Medical Laboratory Technology Department, King Abdulaziz University, Jeddah, Saudi Arabia
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Probing the mechanisms of inhibition for various inhibitors of metallo-β-lactamases VIM-2 and NDM-1. J Inorg Biochem 2020; 210:111123. [PMID: 32622213 DOI: 10.1016/j.jinorgbio.2020.111123] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/28/2020] [Accepted: 05/28/2020] [Indexed: 12/15/2022]
Abstract
To probe the mechanism of inhibition of several previously-published metallo-β-lactamase (MBL) inhibitors for the clinically-important MBL Verona integron-encoded metallo-β-lactamase 2 (VIM-2), equilibrium dialyses with metal analyses, native state electrospray ionization mass spectrometry (ESI-MS), and UV-Vis spectrophotometry were utilized. The mechanisms of inhibition were analyzed for ethylenediaminetetraacetic acid (EDTA); dipicolinic acid (DPA) and DPA analogs 6-(1H-tetrazol-5-yl)picolinic acid (1T5PA) and 4-(3-aminophenyl)pyridine-2,6-dicarboxylic acid (3AP-DPA); thiol-containing compounds, 2,3-dimercaprol, thiorphan, captopril, and tiopronin; and 5-(pyridine-3-sulfonamido)-1,3-thiazole-4-carboxylic acid (ANT-431). UV-Vis spectroscopy and native-state ESI-MS results showed the formation of ternary complexes between VIM-2 and 1T5PA, ANT-431, thiorphan, captopril, and tiopronin, while a metal stripping mechanism was shown with VIM-2 and EDTA and DPA. The same approaches were used to show the formation of a ternary complex between New Delhi Metallo-β-lactamase (NDM-1) and ANT-431. The studies presented herein show that most of the inhibitors utilize a similar mechanism of inhibition as previously reported for NDM-1. These studies also demonstrate that native mass spectrometry can be used to probe the mechanism of inhibition at lower enzyme/inhibitor concentrations than has previously been achieved.
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Evaluating the antimicrobial resistance patterns and molecular frequency of bla oxa-48 and bla GES-2 genes in Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from burn wound infection in Tehran, Iran. New Microbes New Infect 2020; 37:100686. [PMID: 32774866 PMCID: PMC7394744 DOI: 10.1016/j.nmni.2020.100686] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 02/23/2020] [Accepted: 04/16/2020] [Indexed: 02/08/2023] Open
Abstract
The aim of this study is to evaluate the antimicrobial resistance patterns and molecular frequency of blaGES-2 and blaoxa-48 genes in Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from burn wound infection in Tehran, Iran. In this study, 50 isolates of A. baumannii and 48 isolates of P. aeruginosa were collected from the Burn Unit of Shahid Motahari Hospital at Tehran, Iran. Antibiotic susceptibility tests of all isolates were carried out using the disc diffusion method, and the production of extended-spectrum β-lactamases (ESBLs) in isolates was surveyed by the double disc synergy method and based on CLSI (2019 AST M100) criteria. Finally, the frequency of blaGES-2 and blaoxa-48 genes was surveyed by PCR. Antibiotic susceptibility tests showed that 48/48 (100%) of P. aeruginosa isolates and 49/50 (98%) of A. baumannii isolates were resistant to ceftriaxone and cefotaxime, respectively. Ceftazidime exhibited the lowest (26/48; 54.1%) resistance rates against P. aeruginosa isolates. The production of ESBLs was seen in 8/48 (16.6%) and 3/50 (6%) of P. aeruginosa and A. baumannii isolates, respectively. On the basis of conventional PCR and sequencing, the frequencies of the blaGES-2 gene among P. aeruginosa and A. baumannii was 87.5% and 58%, respectively. Moreover, blaoxa-48 gene was detected in 70.83% and 92% of P. aeruginosa and A. baumannii isolates, respectively. Results suggest that antibiotic-resistant A. baumannii and P. aeruginosa strains isolated from burn patients are frequently found; therefore, it is absolutely necessary to implement continuous screening and follow-up programmes for detecting antimicrobial resistance.
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Targeting the Class A Carbapenemase GES-5 via Virtual Screening. Biomolecules 2020; 10:biom10020304. [PMID: 32075131 PMCID: PMC7072645 DOI: 10.3390/biom10020304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 12/29/2022] Open
Abstract
The worldwide spread of β-lactamases able to hydrolyze last resort carbapenems contributes to the antibiotic resistance problem and menaces the successful antimicrobial treatment of clinically relevant pathogens. Class A carbapenemases include members of the KPC and GES families. While drugs against KPC-type carbapenemases have recently been approved, for GES-type enzymes, no inhibitors have yet been introduced in therapy. Thus, GES carbapenemases represent important drug targets. Here, we present an in silico screening against the most prevalent GES carbapenemase, GES-5, using a lead-like compound library of commercially available compounds. The most promising candidates were selected for in vitro validation in biochemical assays against recombinant GES-5 leading to four derivatives active as high micromolar competitive inhibitors. For the best inhibitors, the ability to inhibit KPC-2 was also evaluated. The discovered inhibitors constitute promising starting points for hit to lead optimization.
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Byun JH, Seo Y, Kim D, Kim M, Lee H, Yong D, Lee K, Chong Y. An agar plate-based modified carbapenem inactivation method (p-mCIM) for detection of carbapenemase-producing Enterobacteriaceae. J Microbiol Methods 2019; 168:105781. [PMID: 31756348 DOI: 10.1016/j.mimet.2019.105781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/13/2019] [Accepted: 11/18/2019] [Indexed: 12/15/2022]
Abstract
Detecting carbapenemase-producing Enterobacteriaceae (CPE) has become increasingly difficult due to the emergence of diverse enzymes. The aim of the study was to evaluate an agar plate-based modified carbapenem inactivation method (p-mCIM) for detection of CPE. Stock strains and clinical isolates of CPE were used to evaluate the p-mCIM. The p-mCIM was performed as described for the mCIM, except that meropenem disks were placed on the lawn of test organisms on Mueller-Hinton agar (MHA) plates. Among 17 stock strains of CPE, six of eight KPC-2-like- and all six NDM-1-like carbapenemase-producing strains were positive by the p-mCIM without incubation in the carbapenem inactivation (CI) step. Among 380 CPE clinical isolates detected, 308 and 38 were KPC-2-like and NDM-1-like enzyme producers, respectively. The required incubation time in the CI step to show all isolates were positive by p-mCIM was 3 h for isolates with KPC-2-like enzyme and 1 h for isolates with metallo-β-lactamases. Twenty-eight of 30 isolates with OXA-48-like enzymes were p-mCIM positive. Sensitivities of both the p-mCIM and the mCIM (based on inhibition zone of ≤15 mm) for detection of CPE were 100%. All 70 ertapenem-nonsusceptible, but carbapenemase gene-negative isolates tested were both p-mCIM (based on inhibition zone of ≥21 mm) and mCIM negative. In conclusion, performance of the p-mCIM, which uses a lawn of bacterial colonies on MHA plate instead of a bacteria-suspended Tryptic soy broth tube in the CI step, is essentially identical to that of the CLSI-recommended mCIM in the detection of clinical isolates of Enterobacteriaceae producing carbapenemases including difficult to detect blaOXA-48-like enzymes.
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Affiliation(s)
- Jung-Hyun Byun
- Department of Laboratory Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, (52727) 79 Gangnam-ro, Jinju, Gyeongnam, South Korea
| | - Yonghee Seo
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Severance Hospital, Yonsei University College of Medicine, (03722) 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Daewon Kim
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Severance Hospital, Yonsei University College of Medicine, (03722) 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| | - Myungsook Kim
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Severance Hospital, Yonsei University College of Medicine, (03722) 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| | - Hyukmin Lee
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Severance Hospital, Yonsei University College of Medicine, (03722) 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| | - Dongeun Yong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Severance Hospital, Yonsei University College of Medicine, (03722) 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| | - Kyungwon Lee
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Severance Hospital, Yonsei University College of Medicine, (03722) 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| | - Yunsop Chong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Severance Hospital, Yonsei University College of Medicine, (03722) 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
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Tooke CL, Hinchliffe P, Lang PA, Mulholland AJ, Brem J, Schofield CJ, Spencer J. Molecular Basis of Class A β-Lactamase Inhibition by Relebactam. Antimicrob Agents Chemother 2019; 63:AAC.00564-19. [PMID: 31383664 PMCID: PMC6761529 DOI: 10.1128/aac.00564-19] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/04/2019] [Indexed: 12/23/2022] Open
Abstract
β-Lactamase production is the major β-lactam resistance mechanism in Gram-negative bacteria. β-Lactamase inhibitors (BLIs) efficacious against serine β-lactamase (SBL) producers, especially strains carrying the widely disseminated class A enzymes, are required. Relebactam, a diazabicyclooctane (DBO) BLI, is in phase 3 clinical trials in combination with imipenem for the treatment of infections by multidrug-resistant Enterobacteriaceae We show that relebactam inhibits five clinically important class A SBLs (despite their differing spectra of activity), representing both chromosomal and plasmid-borne enzymes, i.e., the extended-spectrum β-lactamases L2 (inhibition constant 3 μM) and CTX-M-15 (21 μM) and the carbapenemases KPC-2, -3, and -4 (1 to 5 μM). Against purified class A SBLs, relebactam is an inferior inhibitor compared with the clinically approved DBO avibactam (9- to 120-fold differences in half maximal inhibitory concentration [IC50]). MIC assays indicate relebactam potentiates β-lactam (imipenem) activity against KPC-producing Klebsiella pneumoniae, with similar potency to avibactam (with ceftazidime). Relebactam is less effective than avibactam in combination with aztreonam against Stenotrophomonas maltophilia K279a. X-ray crystal structures of relebactam bound to CTX-M-15, L2, KPC-2, KPC-3, and KPC-4 reveal its C2-linked piperidine ring can sterically clash with Asn104 (CTX-M-15) or His/Trp105 (L2 and KPCs), rationalizing its poorer inhibition activity than that of avibactam, which has a smaller C2 carboxyamide group. Mass spectrometry and crystallographic data show slow, pH-dependent relebactam desulfation by KPC-2, -3, and -4. This comprehensive comparison of relebactam binding across five clinically important class A SBLs will inform the design of future DBOs, with the aim of improving clinical efficacy of BLI-β-lactam combinations.
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Affiliation(s)
- Catherine L Tooke
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - Philip Hinchliffe
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - Pauline A Lang
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Jürgen Brem
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | | | - James Spencer
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
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31
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Shurina BA, Page RC. Influence of substrates and inhibitors on the structure of Klebsiella pneumoniae carbapenemase-2. Exp Biol Med (Maywood) 2019; 244:1596-1604. [PMID: 31161945 DOI: 10.1177/1535370219854322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The hydrolysis of last resort carbapenem antibiotics by Klebsiella pneumoniae carbapenemase-2 (KPC-2) presents a significant danger to global health. Combined with horizontal gene transfer, the emergence KPC-2 threatens to quickly expand carbapenemase activity to ever increasing numbers of pathogens. Our understanding of KPC-2 has greatly increased over the past decade thanks, in great part, to 20 crystal structures solved by groups around the world. These include apo KPC-2 structures, along with structures featuring a library of 10 different inhibitors representing diverse structural and functional classes. Herein we focus on cataloging the available KPC-2 structures and presenting a discussion of key aspects of each structure and important relationships between structures. Although the available structures do not provide information on dynamic motions with KPC-2, and the family of structures indicates small conformational changes across a wide array of bound inhibitors, substrates, and products, the structures provide a strong foundation for additional studies in the coming years to discover new KPC-2 inhibitors. Impact statement The work herein is important to the field as it provides a clear and succinct accounting of available KPC-2 structures. The work advances the field by collecting and analyzing differences and similarities across the available structures. This work features new analyses and interpretations of the existing structures which will impact the field in a positive way by making structural insights more widely available among the beta-lactamase community.
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Affiliation(s)
- Ben A Shurina
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Richard C Page
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
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Liu X, Dong S, Ma Y, Xu H, Zhao H, Gao Q. N-(Sulfamoylbenzoyl)-L-proline Derivatives as Potential Non-β-lactam ESBL Inhibitors: Structure-Based Lead Identification, Medicinal Chemistry and Synergistic Antibacterial Activities. Med Chem 2019; 15:196-206. [DOI: 10.2174/1573406414666180816123232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 05/01/2018] [Accepted: 06/04/2018] [Indexed: 11/22/2022]
Abstract
Background:
There is an urgent need to develop novel inhibitors against clinically
widespread extended-spectrum β-lactamases (ESBLs) to meet the challenges of the ever-evolving
threat of antibiotic resistances. Most existing ESBL inhibitors sharing a common chemical feature
of β-lactam ring in their molecule, this structural characteristic makes them intrinsically susceptible
to enzymatic breakdown by the resistance mechanisms employed by the bacteria.
Objective:
The aim of this study was to screen and discover novel lead compounds by using Lproline
as initial scaffold to create a “non-sulfur, non-β-lactam” new chemotypes for potential
ESBL inhibitors.
Methods:
Structure-based molecular docking and virtual screening were employed in the novel
inhibitor generation process for lead compound screening and SAR analysis. Evaluation of the
ESBL inhibitory activity of the lead compounds was performed in combination with three of the
most susceptible antibiotics: ceftazidime, meropenem and ampicillin, against thirteen ESBL enzymes
including four new CTX-M harboring strains and four KPC-2 producing species.
Results:
L-proline derived (S)-1-(2-sulfamoylbenzoyl)pyrrolidine-2-carboxylic acid (compound
6) as a “non-sulfur, non-β-lactam” and the most potential ESBL inhibitor was identified. Compound
6 possesses ideal anti-resistance activities by reducing MICs of ceftazidime, meropenem
and ampicillin by 16-133, 32-133 and 67-267 fold respectiveily. The inhibitory mechanism of 6
with CTX-M, KPC-2 and penicillinase were proposed and probed with molecular docking analysis.
Conclusion:
Given that the simple proline derivative but promising synergistic antibacterial
properties of compound 6 augers well for further investigations into its in vivo efficacy.
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Affiliation(s)
- Xinyu Liu
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Shengjie Dong
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Yuru Ma
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Hu Xu
- Department of Medicinal Chemistry, Gudui BioPharma Technology Inc., 5 Lanyuan Road, Huayuan Industrial Park, Tianjin 300384, China
| | - Hongxia Zhao
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Qingzhi Gao
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
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Spyrakis F, Bellio P, Quotadamo A, Linciano P, Benedetti P, D'Arrigo G, Baroni M, Cendron L, Celenza G, Tondi D. First virtual screening and experimental validation of inhibitors targeting GES-5 carbapenemase. J Comput Aided Mol Des 2019; 33:295-305. [PMID: 30603820 DOI: 10.1007/s10822-018-0182-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 12/20/2018] [Indexed: 12/18/2022]
Abstract
The worldwide spread of beta-lactamases with hydrolytic activity extended to last resort carbapenems is aggravating the antibiotic resistance problem and endangers the successful antimicrobial treatment of clinically relevant pathogens. As recently highlighted by the World Health Organization, new strategies to contain antimicrobial resistance are urgently needed. Class A carbapenemases include members of the KPC, GES and SFC families. These enzymes have the ability to hydrolyse penicillins, cephalosporins and carbapenems, while also being less susceptible to available beta-lactam inhibitors, such as clavulanic acid. The KPC family is the most prevalent. It is mostly found on plasmids in Klebsiella pneumoniae, meaning that great amounts of attention, in terms of inhibitor design and structural biology, have been dedicated to it, whereas no efforts have yet been dedicated to GES-type enzymes, despite their ability to rapidly and horizontally disseminate. We herein report the first in silico screening against GES-5, which is the most dangerous GES-type beta-lactamase, using a library of 800K commercially available candidates that all share drug-like properties, such as their MW, logP, rotatable bonds and HBA/HBD atoms. The best screening results were filtered to enrich the number of different chemotypes, and then submitted to molecular docking. The 34 most promising candidates were selected for in vitro validation in biochemical assays against recombinant GES-5. Six hits acted as inhibitors, in the high micromolar range, towards GES-5 and led to the identification of the first, novel chemotypes with inhibitory activity against this clinically relevant carbapenemase.
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Affiliation(s)
- Francesca Spyrakis
- Department of Drug Science and Technology, University of Turin, Via Giuria 9, 10125, Turin, Italy.
| | - Pierangelo Bellio
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, via Vetoio 1, 67100, L'Aquila, Italy
| | - Antonio Quotadamo
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| | - Pasquale Linciano
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| | - Paolo Benedetti
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy
- Consortium for Computational Molecular and Materials Sciences (CMS), Via Elce di Sotto 8, 06123, Perugia, Italy
| | - Giulia D'Arrigo
- Department of Drug Science and Technology, University of Turin, Via Giuria 9, 10125, Turin, Italy
| | - Massimo Baroni
- Molecular Discovery Limited, U.501 Centennial Park, Centennial Ave, Elstree, Borehamwood, Hertfordshire, WD6 3FG, UK
| | - Laura Cendron
- Department of Biology, University of Padua, Viale G. Colombo 3, 35121, Padua, Italy
| | - Giuseppe Celenza
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, via Vetoio 1, 67100, L'Aquila, Italy
| | - Donatella Tondi
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy.
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P174E Substitution in GES-1 and GES-5 β-Lactamases Improves Catalytic Efficiency toward Carbapenems. Antimicrob Agents Chemother 2018; 62:AAC.01851-17. [PMID: 29507065 DOI: 10.1128/aac.01851-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 02/07/2018] [Indexed: 12/27/2022] Open
Abstract
GES-type β-lactamases are a group of enzymes that have evolved their hydrolytic activity against carbapenems. In this study, the role of residue 174 inside the Ω-loop of GES-1 and GES-5 was investigated. GES-1P174E and GES-5P174E mutants, selected by site saturation mutagenesis, were purified and kinetically characterized. In comparison with GES-1 and GES-5 wild-type enzymes, GES-1P174E and GES-5P174E mutants exhibited lower kcat and kcat/Km values for cephalosporins and penicillins. Concerning carbapenems, GES-1P174E shared higher kcat values but lower Km values than those calculated for GES-1. The GES-1P174E and GES-5P174E mutants showed high hydrolytic efficiency for imipenem, with kcat/Km values 100- and 660-fold higher, respectively, than those of GES-1. Clavulanic acid and tazobactam are good inhibitors for both GES-1P174E and GES-5P174E Molecular dynamic (MD) simulations carried out for GES-1, GES-5, GES-1P174E, and GES-5P174E complexed with imipenem and meropenem have shown that mutation at position 174 induces a drastic increase of enzyme flexibility, in particular in the Ω-loop. The circular dichroism (CD) spectroscopy spectra of the four enzymes indicate that the P174E substitution in GES-1 and GES-5 does not affect the secondary structural content of the enzymes.
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González-Plaza JJ, Šimatović A, Milaković M, Bielen A, Wichmann F, Udiković-Kolić N. Functional Repertoire of Antibiotic Resistance Genes in Antibiotic Manufacturing Effluents and Receiving Freshwater Sediments. Front Microbiol 2018; 8:2675. [PMID: 29387045 PMCID: PMC5776109 DOI: 10.3389/fmicb.2017.02675] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/21/2017] [Indexed: 11/21/2022] Open
Abstract
Environments polluted by direct discharges of effluents from antibiotic manufacturing are important reservoirs for antibiotic resistance genes (ARGs), which could potentially be transferred to human pathogens. However, our knowledge about the identity and diversity of ARGs in such polluted environments remains limited. We applied functional metagenomics to explore the resistome of two Croatian antibiotic manufacturing effluents and sediments collected upstream of and at the effluent discharge sites. Metagenomic libraries built from an azithromycin-production site were screened for resistance to macrolide antibiotics, whereas the libraries from a site producing veterinary antibiotics were screened for resistance to sulfonamides, tetracyclines, trimethoprim, and beta-lactams. Functional analysis of eight libraries identified a total of 82 unique, often clinically relevant ARGs, which were frequently found in clusters and flanked by mobile genetic elements. The majority of macrolide resistance genes identified from matrices exposed to high levels of macrolides were similar to known genes encoding ribosomal protection proteins, macrolide phosphotransferases, and transporters. Potentially novel macrolide resistance genes included one most similar to a 23S rRNA methyltransferase from Clostridium and another, derived from upstream unpolluted sediment, to a GTPase HflX from Emergencia. In libraries deriving from sediments exposed to lower levels of veterinary antibiotics, we found 8 potentially novel ARGs, including dihydrofolate reductases and beta-lactamases from classes A, B, and D. In addition, we detected 7 potentially novel ARGs in upstream sediment, including thymidylate synthases, dihydrofolate reductases, and class D beta-lactamase. Taken together, in addition to finding known gene types, we report the discovery of novel and diverse ARGs in antibiotic-polluted industrial effluents and sediments, providing a qualitative basis for monitoring the dispersal of ARGs from environmental hotspots such as discharge sites of pharmaceutical effluents.
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Affiliation(s)
- Juan J González-Plaza
- Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ana Šimatović
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Milena Milaković
- Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ana Bielen
- Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
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Pemberton OA, Zhang X, Chen Y. Molecular Basis of Substrate Recognition and Product Release by the Klebsiella pneumoniae Carbapenemase (KPC-2). J Med Chem 2017; 60:3525-3530. [PMID: 28388065 DOI: 10.1021/acs.jmedchem.7b00158] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Carbapenem-resistant Enterobacteriaceae are resistant to most β-lactam antibiotics due to the production of the Klebsiella pneumoniae carbapenemase (KPC-2) class A β-lactamase. Here, we present the first product complex crystal structures of KPC-2 with β-lactam antibiotics containing hydrolyzed cefotaxime and faropenem. They provide experimental insights into substrate recognition by KPC-2 and its unique cephalosporinase/carbapenemase activity. These structures also represent the first product complexes for a wild-type serine β-lactamase, elucidating the product release mechanism of these enzymes in general.
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Affiliation(s)
- Orville A Pemberton
- Department of Molecular Medicine, University of South Florida , 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
| | - Xiujun Zhang
- Department of Molecular Medicine, University of South Florida , 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida , 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
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Smith CA, Nossoni Z, Toth M, Stewart NK, Frase H, Vakulenko SB. Role of the Conserved Disulfide Bridge in Class A Carbapenemases. J Biol Chem 2016; 291:22196-22206. [PMID: 27590339 PMCID: PMC5063999 DOI: 10.1074/jbc.m116.749648] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/31/2016] [Indexed: 08/30/2023] Open
Abstract
Some members of the class A β-lactamase family are capable of conferring resistance to the last resort antibiotics, carbapenems. A unique structural feature of these clinically important enzymes, collectively referred to as class A carbapenemases, is a disulfide bridge between invariant Cys69 and Cys238 residues. It was proposed that this conserved disulfide bridge is responsible for their carbapenemase activity, but this has not yet been validated. Here we show that disruption of the disulfide bridge in the GES-5 carbapenemase by the C69G substitution results in only minor decreases in the conferred levels of resistance to the carbapenem imipenem and other β-lactams. Kinetic and circular dichroism experiments with C69G-GES-5 demonstrate that this small drop in antibiotic resistance is due to a decline in the enzyme activity caused by a marginal loss of its thermal stability. The atomic resolution crystal structure of C69G-GES-5 shows that two domains of this disulfide bridge-deficient enzyme are held together by an intensive hydrogen-bonding network. As a result, the protein architecture and imipenem binding mode remain unchanged. In contrast, the corresponding hydrogen-bonding networks in NMCA, SFC-1, and SME-1 carbapenemases are less intensive, and as a consequence, disruption of the disulfide bridge in these enzymes destabilizes them, which causes arrest of bacterial growth. Our results demonstrate that the disulfide bridge is essential for stability but does not play a direct role in the carbapenemase activity of the GES family of β-lactamases. This would likely apply to all other class A carbapenemases given the high degree of their structural similarity.
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Affiliation(s)
- Clyde A Smith
- From the Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California 94025 and
| | - Zahra Nossoni
- the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Marta Toth
- the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Nichole K Stewart
- the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Hilary Frase
- the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Sergei B Vakulenko
- the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
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Prevalence and Fate of Carbapenemase Genes in a Wastewater Treatment Plant in Northern China. PLoS One 2016; 11:e0156383. [PMID: 27227329 PMCID: PMC4882038 DOI: 10.1371/journal.pone.0156383] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 05/15/2016] [Indexed: 01/09/2023] Open
Abstract
Carbapenemase-producing strains of bacteria, which were primarily found in the medical field, have increasingly been found in the environment, thus posing potential risks to public health. One possible way for carbapenemase genes to enter the environment is via wastewater. Therefore, the goal of this study was to determine the occurrence and fate of five high-risk carbapenemase genes in a wastewater treatment plant (WWTP) in northern China using real-time qPCR. Results showed that the blaKPC-2, blaGES-1, and blaIMP-1 genes prevailed throughout all processing stages (even in the chlorination disinfection unit) in the WWTP, whereas the blaVIM-2 and blaOXA-48 genes were not detected in all samples. Worryingly, considerable amounts of carbapenemase genes ((1.54 ± 0.61) × 103 copies/mL to (2.14± 0.41) × 105 copies/mL) were detected in WWTP effluent samples, while the majority of the carbapenemase genes were transported to the dewatered sludge with concentrations from (6.51 ± 0.14) × 109 copies/g to (6.18 ± 0.63) × 1010 copies/g dry weight. Furthermore, a total of 97 KPC-2-producing strains, belonging to 8 bacterial genera, were isolated from the WWTP. Sequencing of 16S rRNA revealed that most of KPC-2 producing isolates were opportunistic pathogens, including Klebsiella spp. (10.3%), Enterococcus spp. (11.3%), Acinetobacter spp. (19.6%), Escherichia spp. (12.4%), Shigella spp. (17.5%), Stenotrophomonas spp. (10.3%) and Wautersiella spp. (9.3%). Moreover, blaKPC-2 genes were identified for the first time in Paenibacillus spp. isolates (an indigenous bacteria), indicating an increased risk of horizontal transfer between clinical pathogens and environmental bacteria. Indeed, a conjugation experiment demonstrated transfer of the blaKPC-2 gene to an E.coli J53 strain from a Klebsiella strain isolated from the WWTP. To our knowledge, this is the first study to obtain Paenibacillus spp. isolates carrying the carbapenemase gene and to quantify the abundance of carbapenemase genes in the environment.
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Naas T, Dortet L, Iorga BI. Structural and Functional Aspects of Class A Carbapenemases. Curr Drug Targets 2016; 17:1006-28. [PMID: 26960341 PMCID: PMC5405625 DOI: 10.2174/1389450117666160310144501] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/02/2015] [Accepted: 03/05/2016] [Indexed: 01/28/2023]
Abstract
The fight against infectious diseases is probably one of the greatest public health challenges faced by our society, especially with the emergence of carbapenem-resistant gram-negatives that are in some cases pan-drug resistant. Currently,β-lactamase-mediated resistance does not spare even the newest and most powerful β-lactams (carbapenems), whose activity is challenged by carbapenemases. The worldwide dissemination of carbapenemases in gram-negative organisms threatens to take medicine back into the pre-antibiotic era since the mortality associated with infections caused by these "superbugs" is very high, due to limited treatment options. Clinically-relevant carbapenemases belong either to metallo-β- lactamases (MBLs) of Ambler class B or to serine-β-lactamases (SBLs) of Ambler class A and D enzymes. Class A carbapenemases may be chromosomally-encoded (SME, NmcA, SFC-1, BIC-1, PenA, FPH-1, SHV-38), plasmid-encoded (KPC, GES, FRI-1) or both (IMI). The plasmid-encoded enzymes are often associated with mobile elements responsible for their mobilization. These enzymes, even though weakly related in terms of sequence identities, share structural features and a common mechanism of action. They variably hydrolyse penicillins, cephalosporins, monobactams, carbapenems, and are inhibited by clavulanate and tazobactam. Three-dimensional structures of class A carbapenemases, in the apo form or in complex with substrates/inhibitors, together with site-directed mutagenesis studies, provide essential input for identifying the structural factors and subtle conformational changes that influence the hydrolytic profile and inhibition of these enzymes. Overall, these data represent the building blocks for understanding the structure-function relationships that define the phenotypes of class A carbapenemases and can guide the design of new molecules of therapeutic interest.
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Affiliation(s)
- Thierry Naas
- Service de Bactériologie- Hygiène, Hôpital de Bicêtre, APHP, EA7361, Faculté de Médecine Paris- Sud, LabEx LERMIT, Le Kremlin-Bicêtre, France.
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Class D β-lactamases do exist in Gram-positive bacteria. Nat Chem Biol 2015; 12:9-14. [PMID: 26551395 PMCID: PMC4684797 DOI: 10.1038/nchembio.1950] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/22/2015] [Indexed: 12/22/2022]
Abstract
Production of β-lactamases of the four molecular classes (A, B, C, and D) is the major mechanism of bacterial resistance to β-lactams, the largest class of antibiotics that have saved countless lives since their inception 70 years ago. Although several hundred efficient class D enzymes have been identified in Gram-negative pathogens over the last four decades, they have not been reported in Gram-positive bacteria. Here we demonstrate that efficient class D β-lactamases capable of hydrolyzing a wide array of β-lactam substrates are widely disseminated in various species of environmental Gram-positive organisms. Class D enzymes of Gram-positive bacteria have a distinct structural architecture and employ a unique substrate binding mode quite different from that of all currently known class A, C, and D β-lactamases. They constitute a novel reservoir of antibiotic resistance enzymes.
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Structural basis for carbapenem-hydrolyzing mechanisms of carbapenemases conferring antibiotic resistance. Int J Mol Sci 2015; 16:9654-92. [PMID: 25938965 PMCID: PMC4463611 DOI: 10.3390/ijms16059654] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 02/06/2023] Open
Abstract
Carbapenems (imipenem, meropenem, biapenem, ertapenem, and doripenem) are β-lactam antimicrobial agents. Because carbapenems have the broadest spectra among all β-lactams and are primarily used to treat infections by multi-resistant Gram-negative bacteria, the emergence and spread of carbapenemases became a major public health concern. Carbapenemases are the most versatile family of β-lactamases that are able to hydrolyze carbapenems and many other β-lactams. According to the dependency of divalent cations for enzyme activation, carbapenemases can be divided into metallo-carbapenemases (zinc-dependent class B) and non-metallo-carbapenemases (zinc-independent classes A, C, and D). Many studies have provided various carbapenemase structures. Here we present a comprehensive and systematic review of three-dimensional structures of carbapenemase-carbapenem complexes as well as those of carbapenemases. We update recent studies in understanding the enzymatic mechanism of each class of carbapenemase, and summarize structural insights about regions and residues that are important in acquiring the carbapenemase activity.
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