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Chikunova A, Manley MP, Heijjer CN, Drenth CS, Cramer-Blok AJ, Ahmad MUD, Perrakis A, Ubbink M. Conserved proline residues prevent dimerization and aggregation in the β-lactamase BlaC. Protein Sci 2024; 33:e4972. [PMID: 38533527 DOI: 10.1002/pro.4972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 03/28/2024]
Abstract
Evolution leads to conservation of amino acid residues in protein families. Conserved proline residues are usually considered to ensure the correct folding and to stabilize the three-dimensional structure. Surprisingly, proline residues that are highly conserved in class A β-lactamases were found to tolerate various substitutions without large losses in enzyme activity. We investigated the roles of three conserved prolines at positions 107, 226, and 258 in the β-lactamase BlaC from Mycobacterium tuberculosis and found that mutations can lead to dimerization of the enzyme and an overall less stable protein that is prone to aggregate over time. For the variant Pro107Thr, the crystal structure shows dimer formation resembling domain swapping. It is concluded that the proline substitutions loosen the structure, enhancing multimerization. Even though the enzyme does not lose its properties without the conserved proline residues, the prolines ensure the long-term structural integrity of the enzyme.
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Affiliation(s)
- A Chikunova
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - M P Manley
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - C N Heijjer
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - C S Drenth
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - A J Cramer-Blok
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - M Ud Din Ahmad
- Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - A Perrakis
- Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Oncode Institute, Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - M Ubbink
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Department of Infectious Diseases, Imperial College, London, UK
- Zocdoc, New York City, New York, USA
- ZoBio BV, Leiden, The Netherlands
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2
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Xia L, Xu X, Li M, Zhang X, Cao F. Afzelin induces immunogenic cell death against lung cancer by targeting NQO2. BMC Complement Med Ther 2023; 23:381. [PMID: 37891619 PMCID: PMC10605937 DOI: 10.1186/s12906-023-04221-3] [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: 02/27/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023] Open
Abstract
BACKGROUND Lung cancer is one of the most common malignant cancers worldwide. Previous studies have shown that Afzelin, a flavonoid, possesses anticancer activity. The aim of this study was to explore Afzelin's effect on lung cancer cells and delineate potential anti-cancer mechanism. METHODS The effect of Afzelin on cell viability, proliferation, and apoptosis of lung cancer cells i.e., A549 and H1299 cells, was studied. The targets for Afzelin in lung cancer were predicted using SwissTargetPrediction, Next, the GO analysis and pathway enrichment were analyzed using String. For in vitro studies, the overexpression plasmid of NQO2, the identified target of Afzelin, was transfected into Afzelin-treated cells to verify the regulatory role of Afzelin on its target and signaling pathway. RESULTS In in vitro studies, Afzelin markedly inhibited cell viability, proliferation, and raised apoptotic rate of A549 and H1299 cells. In addition, Afzelin activated endoplasmic reticulum (ER) stress and increased ATP, HMGB1, and CRT levels in lung cancer cells, indicating that Afzelin induced immunogenic cell death (ICD). SwissTargetPrediction identified NQO2 as a target of Afzelin. Further, Afzelin markedly inhibited NQO2 protein expression and in turn, overexpression of NQO2 attenuated the effect of Afzelin on A549 and H1299 cells. CONCLUSION Afzelin inhibits lung cancer progression by targeting NQO2, in turn, activating ER stress and inducing ICD.
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Affiliation(s)
- Lei Xia
- Department of Medical Oncology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, No. 16369, Jingshi Road, Jinan, Shandong, 250000, China
| | - Xiaoqing Xu
- The First Clinical College, Shandong University of Traditional Chinese Medicine, Jinan, 250355, Shandong, China
| | - Meijun Li
- Department of Traditional Chinese Medicine, Zibo Central Hospital, Zibo, 255036, Shandong, China
| | - Xinyue Zhang
- The First Clinical College, Shandong University of Traditional Chinese Medicine, Jinan, 250355, Shandong, China
| | - Fang Cao
- Department of Medical Oncology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, No. 16369, Jingshi Road, Jinan, Shandong, 250000, China.
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Özen A, Elif Öztürkkan F, Uğurlu G, Akbaba GB, Sertçelik M, Hökelek T, Necefoğlu H. 4-(3-oxo-1,3-dihydroisobenzofuran-1-yl)aminobenzoic acid and its complexes: Synthesis, Crystal Structures, Theoretical Calculations and In Vitro and In silico Antibacterial Properties. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2023.134932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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4
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In vitro activity of celastrol in combination with thymol against carbapenem-resistant Klebsiella pneumoniae isolates. J Antibiot (Tokyo) 2022; 75:679-690. [PMID: 36167781 DOI: 10.1038/s41429-022-00566-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/03/2022] [Accepted: 09/06/2022] [Indexed: 12/26/2022]
Abstract
Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial and community-acquired infections. Klebsiella has developed resistance against antimicrobials including the last resort class; carbapenem. Currently, treatment options for carbapenem-resistant-Klebsiella (CRK) are very limited. This study aims to restore carbapenem effectiveness against CRK using celastrol and thymol. Clinical Klebsiella isolates were identified using biochemical and molecular methods. Antimicrobial susceptibility was determined using disk-diffusion method. Carbapenemase-production was tested phenotypically and genotypically. Celastrol and thymol-MICs were determined and the carbapenemase-inhibitory effect of sub-MICs was investigated. Among 85 clinical Klebsiella isolates, 72 were multi-drug-resistant and 43 were meropenem-resistant. Phenotypically, 39 isolates were carbapenemase-producer. Genotypically, blaNDM1 was detected in 35 isolates, blaVIM in 17 isolates, blaOXA in 18 isolates, and blaKPC was detected only in 6 isolates. Celastrol showed significant inhibitory effect against carbapenemase-hydrolytic activity. Meropenem-MIC did not decrease in presence of celastrol, only 2-fold decrease was observed with thymol, while 4-64 fold decrease was observed when meropenem was combined with both celastrol and thymol. Furthermore, thymol increased CRK cell wall-permeability. Molecular docking revealed that celastrol is superior to thymol for binding to KPC and VIM-carbapenemase. Our study showed that celastrol is a promising inhibitor of multiple carbapenemases. While meropenem-MIC were not affected by celastrol alone and decreased by only 2-folds with thymol, it decreased by 4-64 folds in presence of both celastrol and thymol. Thymol increases the permeability of CRK-envelope to celastrol. The triple combination (meropenem/celastrol/thymol) could be useful for developing more safe and effective analogues to restore the activity of meropenem and other β-lactams.
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Lund BA, Thomassen AM, Carlsen TJW, Leiros HKS. Biochemical and biophysical characterization of the OXA-48-like carbapenemase OXA-436. Acta Crystallogr F Struct Biol Commun 2021; 77:312-318. [PMID: 34473108 PMCID: PMC8411929 DOI: 10.1107/s2053230x21008645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/18/2021] [Indexed: 11/08/2023] Open
Abstract
The crystal structure of the class D β-lactamase OXA-436 was solved to a resolution of 1.80 Å. Higher catalytic rates were found at higher temperatures for the clinically important antibiotic imipenem, indicating better adaptation of OXA-436 to its mesophilic host than OXA-48, which is believed to originate from an environmental source. Furthermore, based on the most populated conformations during 100 ns molecular-dynamics simulations, it is postulated that the modulation of activity involves conformational shifts of the α3-α4 and β5-β6 loops. While these changes overall do not cause clinically significant shifts in the resistance profile, they show that antibiotic-resistance enzymes exist in a continuum. It is believed that these seemingly neutral differences in the sequence exist on a path leading to significant changes in substrate selectivity.
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Affiliation(s)
- Bjarte Aarmo Lund
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway
| | - Ane Molden Thomassen
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway
| | - Trine Josefine Warg Carlsen
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway
| | - Hanna-Kirsti Schrøder Leiros
- The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway
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Abstract
Very low antibiotic concentrations have been shown to drive the evolution of antimicrobial resistance. While substantial progress has been made to understand the driving role of low concentrations during resistance development for different antimicrobial classes, the importance of β-lactams, the most commonly used antibiotics, is still poorly studied. Our current understanding of how low antibiotic concentrations shape the evolution of contemporary β-lactamases is limited. Using the widespread carbapenemase OXA-48, we tested the long-standing hypothesis that selective compartments with low antibiotic concentrations cause standing genetic diversity that could act as a gateway to developing clinical resistance. Here, we subjected Escherichia coli expressing blaOXA-48, on a clinical plasmid, to experimental evolution at sub-MICs of ceftazidime. We identified and characterized seven single variants of OXA-48. Susceptibility profiles and dose-response curves showed that they increased resistance only marginally. However, in competition experiments at sub-MICs of ceftazidime, they demonstrated strong selectable fitness benefits. Increased resistance was also reflected in elevated catalytic efficiencies toward ceftazidime. These changes are likely caused by enhanced flexibility of the Ω- and β5-β6 loops and fine-tuning of preexisting active site residues. In conclusion, low-level concentrations of β-lactams can drive the evolution of β-lactamases through cryptic phenotypes which may act as stepping-stones toward clinical resistance. IMPORTANCE Very low antibiotic concentrations have been shown to drive the evolution of antimicrobial resistance. While substantial progress has been made to understand the driving role of low concentrations during resistance development for different antimicrobial classes, the importance of β-lactams, the most commonly used antibiotics, is still poorly studied. Here, we shed light on the evolutionary impact of low β-lactam concentrations on the widespread β-lactamase OXA-48. Our data indicate that the exposure to β-lactams at very low concentrations enhances β-lactamase diversity and drives the evolution of β-lactamases by significantly influencing their substrate specificity. Thus, in contrast to high concentrations, low levels of these drugs may substantially contribute to the diversification and divergent evolution of these enzymes, providing a standing genetic diversity that can be selected and mobilized when antibiotic pressure increases.
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7
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Dabos L, Zavala A, Bonnin RA, Beckstein O, Retailleau P, Iorga BI, Naas T. Substrate Specificity of OXA-48 after β5-β6 Loop Replacement. ACS Infect Dis 2020; 6:1032-1043. [PMID: 32156115 DOI: 10.1021/acsinfecdis.9b00452] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OXA-48 carbapenemase has rapidly spread in many countries worldwide with several OXA-48-variants being described, differing by a few amino acid (AA) substitutions or deletions, mostly in the β5-β6 loop. While single AA substitutions have only a minor impact on OXA-48 hydrolytic profiles, others with 4 AA deletions result in loss of carbapenem hydrolysis and gain of expanded-spectrum cephalosporin (ESC) hydrolysis. We have replaced the β5-β6 loop of OXA-48 with that of OXA-18, a clavulanic-acid inhibited oxacillinase capable of hydrolyzing ESCs but not carbapenems. The hybrid enzyme OXA-48Loop18 was able to hydrolyze ESCs and carbapenems (although with a lower kcat), even though the β5-β6 loop was longer and its sequence quite different from that of OXA-48. The kinetic parameters of OXA-48Loop18 were in agreement with the MIC values. X-ray crystallography and molecular modeling suggest that the conformation of the grafted loop allows the binding of bulkier substrates, unlike that of the native loop, expanding the hydrolytic profile. This seems to be due not only to differences in AA sequence, but also to the backbone conformation the loop can adopt. Finally, our results provide further experimental evidence for the role of the β5-β6 loop in substrate selectivity of OXA-48-like enzymes and additional details on the structure-function relationship of β-lactamases, demonstrating how localized changes in these proteins can alter or expand their function, highlighting their plasticity.
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Affiliation(s)
- Laura Dabos
- EA7361 “Structure, Dynamic, Function and Expression of Broad Spectrum β-Lactamases”, Université Paris Sud, Université Paris Saclay, LabEx Lermit, Faculty of Medicine, 94270 Le Kremlin-Bicêtre, France
- Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur−APHP−Université Paris Sud, 75015 Paris, France
| | - Agustin Zavala
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Saclay, Labex LERMIT, 91190 Gif-sur-Yvette, France
| | - Rémy A. Bonnin
- EA7361 “Structure, Dynamic, Function and Expression of Broad Spectrum β-Lactamases”, Université Paris Sud, Université Paris Saclay, LabEx Lermit, Faculty of Medicine, 94270 Le Kremlin-Bicêtre, France
- Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur−APHP−Université Paris Sud, 75015 Paris, France
- Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-Producing Enterobacteriaceae, 94270 Le Kremlin-Bicêtre, France
| | - Oliver Beckstein
- Department of Physics and Center for Biological Physics, Arizona State University, Tempe, 85281 Arizona, United States
| | - Pascal Retailleau
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Saclay, Labex LERMIT, 91190 Gif-sur-Yvette, France
| | - Bogdan I. Iorga
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Saclay, Labex LERMIT, 91190 Gif-sur-Yvette, France
| | - Thierry Naas
- EA7361 “Structure, Dynamic, Function and Expression of Broad Spectrum β-Lactamases”, Université Paris Sud, Université Paris Saclay, LabEx Lermit, Faculty of Medicine, 94270 Le Kremlin-Bicêtre, France
- Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur−APHP−Université Paris Sud, 75015 Paris, France
- Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-Producing Enterobacteriaceae, 94270 Le Kremlin-Bicêtre, France
- Bacteriology-Hygiene Unit, Assistance Publique/Hôpitaux de Paris, Bicêtre Hospital, 94270 Le Kremlin-Bicêtre, France
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8
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Hirvonen VHA, Mulholland AJ, Spencer J, van der Kamp MW. Small Changes in Hydration Determine Cephalosporinase Activity of OXA-48 β-Lactamases. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00596] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Viivi H. A. Hirvonen
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD United Kingdom
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS United Kingdom
| | - Adrian J. Mulholland
- 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, University Walk, Bristol, BS8 1TD United Kingdom
| | - Marc W. van der Kamp
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD United Kingdom
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS United Kingdom
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Role of Arginine 214 in the Substrate Specificity of OXA-48. Antimicrob Agents Chemother 2020; 64:AAC.02329-19. [PMID: 32071047 DOI: 10.1128/aac.02329-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/11/2020] [Indexed: 11/20/2022] Open
Abstract
Increasing numbers of variants of the carbapenem-hydrolyzing class D β-lactamase OXA-48 are identified in Enterobacterales worldwide. Among them, OXA-181 and OXA-232 are of particular interest, as they differ from each other by a single amino acid substitution at position 214 (R in OXA-181 and S in OXA-232) that results in reduced carbapenem-hydrolyzing activity for OXA-232. To investigate the role of amino acid position 214 (AA214), the X-ray structure of OXA-232 was determined and AA214 of OXA-48 and of OXA-232 was replaced by G, L, D, E, S, R, and K using site-directed mutagenesis. These mutants were phenotypically characterized, and three mutants of OXA-232 were purified to study their steady-state kinetic properties. The X-ray structure of OXA-232 along with molecular modeling studies showed that the interaction via a salt bridge between R214 and D159 in OXA-48 is not possible with the G214 or S214 mutation. In contrast, with K214, which is also positively charged, the interaction with D159 is maintained. With the E214 mutant, an alternative binding conformation of imipenem that is not compatible with a nucleophilic attack by S70 was evidenced. Thus, imipenem has a very poor apparent affinity for the E214 mutant because of its nonproductive binding mode. Similarly, we could explain the lack of temocillin hydrolysis by the OXA-232-S214E mutant, which is due to the unfavorable interaction between the negatively charged R1 substituent of temocillin with the E214 residue. Overall, we demonstrate that AA214 in OXA-48-like β-lactamases is critical for the carbapenemase activity.
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Oueslati S, Retailleau P, Marchini L, Dortet L, Bonnin RA, Iorga BI, Naas T. Biochemical and Structural Characterization of OXA-405, an OXA-48 Variant with Extended-Spectrum β-Lactamase Activity. Microorganisms 2019; 8:microorganisms8010024. [PMID: 31877796 PMCID: PMC7022249 DOI: 10.3390/microorganisms8010024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 12/18/2019] [Indexed: 12/23/2022] Open
Abstract
OXA-48-producing Enterobacterales have now widely disseminated globally. A sign of their extensive spread is the identification of an increasing number of OXA-48 variants. Among them, three are particularly interesting, OXA-163, OXA-247 and OXA-405, since they have lost carbapenem activities and gained expanded-spectrum cephalosporin hydrolytic activity subsequent to a four amino-acid (AA) deletion in the β5–β6 loop. We investigated the mechanisms responsible for substrate specificity of OXA-405. Kinetic parameters confirmed that OXA-405 has a hydrolytic profile compatible with an ESBL (hydrolysis of expanded spectrum cephalosporins and susceptibility to class A inhibitors). Molecular modeling techniques and 3D structure determination show that the overall dimeric structure of OXA-405 is very similar to that of OXA-48, except for the β5–β6 loop, which is shorter for OXA-405, suggesting that the length of the β5–β6 loop is critical for substrate specificity. Covalent docking with selected substrates and molecular dynamics simulations evidenced the structural changes induced by substrate binding, as well as the distribution of water molecules in the active site and their role in substrate hydrolysis. All this data may represent the structural basis for the design of new and efficient class D inhibitors.
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Affiliation(s)
- Saoussen Oueslati
- EA7361 “Structure, dynamic, function and expression of broad spectrum β-lactamases”, Faculty of Medicine of Paris-Sud University, Labex LERMIT, University Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (S.O.); (L.D.); (R.A.B.)
| | - Pascal Retailleau
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Labex LERMIT, 91198 Gif-sur-Yvettte, France; (P.R.); (L.M.); (B.I.I.)
| | - Ludovic Marchini
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Labex LERMIT, 91198 Gif-sur-Yvettte, France; (P.R.); (L.M.); (B.I.I.)
| | - Laurent Dortet
- EA7361 “Structure, dynamic, function and expression of broad spectrum β-lactamases”, Faculty of Medicine of Paris-Sud University, Labex LERMIT, University Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (S.O.); (L.D.); (R.A.B.)
- French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, 94270 Le Kremlin-Bicêtre, France
- Bacteriology-Hygiene unit, Bicêtre Hospital, Assistance Publique/Hôpitaux de Paris, 94270 Le Kremlin-Bicêtre, France
| | - Rémy A. Bonnin
- EA7361 “Structure, dynamic, function and expression of broad spectrum β-lactamases”, Faculty of Medicine of Paris-Sud University, Labex LERMIT, University Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (S.O.); (L.D.); (R.A.B.)
- French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, 94270 Le Kremlin-Bicêtre, France
| | - Bogdan I. Iorga
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Labex LERMIT, 91198 Gif-sur-Yvettte, France; (P.R.); (L.M.); (B.I.I.)
| | - Thierry Naas
- EA7361 “Structure, dynamic, function and expression of broad spectrum β-lactamases”, Faculty of Medicine of Paris-Sud University, Labex LERMIT, University Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (S.O.); (L.D.); (R.A.B.)
- French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, 94270 Le Kremlin-Bicêtre, France
- Bacteriology-Hygiene unit, Bicêtre Hospital, Assistance Publique/Hôpitaux de Paris, 94270 Le Kremlin-Bicêtre, France
- Correspondence: ; Tel.: +33-1-45-21-20-19; Fax: +33-1-45-21-63-40
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Abstract
Surveillance studies have shown that OXA-48-like carbapenemases are the most common carbapenemases in Enterobacterales in certain regions of the world and are being introduced on a regular basis into regions of nonendemicity, where they are responsible for nosocomial outbreaks. OXA-48, OXA-181, OXA-232, OXA-204, OXA-162, and OXA-244, in that order, are the most common enzymes identified among the OXA-48-like carbapenemase group. OXA-48 is associated with different Tn1999 variants on IncL plasmids and is endemic in North Africa and the Middle East. OXA-162 and OXA-244 are derivatives of OXA-48 and are present in Europe. OXA-181 and OXA-232 are associated with ISEcp1, Tn2013 on ColE2, and IncX3 types of plasmids and are endemic in the Indian subcontinent (e.g., India, Bangladesh, Pakistan, and Sri Lanka) and certain sub-Saharan African countries. Overall, clonal dissemination plays a minor role in the spread of OXA-48-like carbapenemases, but certain high-risk clones (e.g., Klebsiella pneumoniae sequence type 147 [ST147], ST307, ST15, and ST14 and Escherichia coli ST38 and ST410) have been associated with the global dispersion of OXA-48, OXA-181, OXA-232, and OXA-204. Chromosomal integration of bla OXA-48 within Tn6237 occurred among E. coli ST38 isolates, especially in the United Kingdom. The detection of Enterobacterales with OXA-48-like enzymes using phenotypic methods has improved recently but remains challenging for clinical laboratories in regions of nonendemicity. Identification of the specific type of OXA-48-like enzyme requires sequencing of the corresponding genes. Bacteria (especially K. pneumoniae and E. coli) with bla OXA-48, bla OXA-181, and bla OXA-232 are emerging in different parts of the world and are most likely underreported due to problems with the laboratory detection of these enzymes. The medical community should be aware of the looming threat that is posed by bacteria with OXA-48-like carbapenemases.
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12
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Abstract
Infections due to carbapenemase-producing Gram-negative pathogens are associated with limited treatment options and consequently lead to increased mortality and morbidity. In response, combinations of existing β-lactams and novel β-lactamase inhibitors, such as ceftazidime-avibactam (CAZ-AVI), have been developed as alternative treatment options. To understand the development of resistance and evolutionary trajectories under CAZ-AVI exposure, we studied the effects of ceftazidime (CAZ) and CAZ-AVI on the carbapenemase OXA-48 and the epidemic OXA-48 plasmid in Escherichia coli Exposure of CAZ and CAZ-AVI resulted in single (P68A) and double (P68A,Y211S) amino acid substitutions in OXA-48, respectively. The antimicrobial susceptibility data and enzyme kinetics showed that the P68A substitution was responsible for an increased activity toward CAZ, whereas P68A,Y211S led to a decrease in the inhibitory activity of AVI. X-ray crystallography and molecular modeling of the mutants demonstrated increased flexibility within the active site, which could explain the elevated CAZ hydrolysis and reduced inhibitory activity of AVI. Interestingly, these substitutions resulted in collateral effects compromising the activity of OXA-48 toward carbapenems and penicillins. Moreover, exposure to CAZ-AVI selected for mutations within the OXA-48-encoding plasmid that severely reduced fitness in the absence of antimicrobial selection. These evolutionary trade-offs may contribute to limit the evolution of OXA-48-mediated CAZ and CAZ-AVI resistance, as well as potentially resensitize isolates toward other therapeutic alternatives.IMPORTANCE The recent introduction of novel β-lactam/β-lactamase inhibitor combinations like ceftazidime-avibactam has increased our ability to treat infections caused by multidrug-resistant Gram-negative bacteria, including carbapenemase-producing Enterobacterales However, the increasing number of cases of reported resistance to ceftazidime-avibactam is a concern. OXA-48 is a carbapenemase that has no significant effect on ceftazidime, but is inhibited by avibactam. Since isolates with OXA-48 frequently harbor extended-spectrum β-lactamases that are inhibited by avibactam, it is likely that ceftazidime-avibactam will be used to treat infections caused by OXA-48-producing Enterobacterales. Our data show that exposure to ceftazidime-avibactam can lead to changes in OXA-48, resulting in increased ability to hydrolyze ceftazidime and withstand the inhibitory effect of avibactam. Thus, resistance toward ceftazidime-avibactam among OXA-48-producing Enterobacterales should be monitored. Interestingly, the compromising effect of the amino acid substitutions in OXA-48 on other β-lactams and the effect of ceftazidime-avibactam exposure on the epidemic OXA-48 plasmid indicate that the evolution of ceftazidime-avibactam resistance comes with collateral effects.
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