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Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering
The emergence of Klebsiella pneumoniae carbapenemases (KPCs), β-lactamases that inactivate “last-line” antibiotics such as imipenem, represents a major challenge to contemporary antibiotic therapies. The combination of ceftazidime (CAZ) and avibactam (AVI), a potent β-lactamase inhibitor, represents...
Autores principales: | , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Microbiology
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5666153/ https://www.ncbi.nlm.nih.gov/pubmed/29089425 http://dx.doi.org/10.1128/mBio.00528-17 |
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author | Barnes, Melissa D. Winkler, Marisa L. Taracila, Magdalena A. Page, Malcolm G. Desarbre, Eric Kreiswirth, Barry N. Shields, Ryan K. Nguyen, Minh-Hong Clancy, Cornelius Spellberg, Brad Papp-Wallace, Krisztina M. Bonomo, Robert A. |
author_facet | Barnes, Melissa D. Winkler, Marisa L. Taracila, Magdalena A. Page, Malcolm G. Desarbre, Eric Kreiswirth, Barry N. Shields, Ryan K. Nguyen, Minh-Hong Clancy, Cornelius Spellberg, Brad Papp-Wallace, Krisztina M. Bonomo, Robert A. |
author_sort | Barnes, Melissa D. |
collection | PubMed |
description | The emergence of Klebsiella pneumoniae carbapenemases (KPCs), β-lactamases that inactivate “last-line” antibiotics such as imipenem, represents a major challenge to contemporary antibiotic therapies. The combination of ceftazidime (CAZ) and avibactam (AVI), a potent β-lactamase inhibitor, represents an attempt to overcome this formidable threat and to restore the efficacy of the antibiotic against Gram-negative bacteria bearing KPCs. CAZ-AVI-resistant clinical strains expressing KPC variants with substitutions in the Ω-loop are emerging. We engineered 19 KPC-2 variants bearing targeted mutations at amino acid residue Ambler position 179 in Escherichia coli and identified a unique antibiotic resistance phenotype. We focus particularly on the CAZ-AVI resistance of the clinically relevant Asp179Asn variant. Although this variant demonstrated less hydrolytic activity, we demonstrated that there was a prolonged period during which an acyl-enzyme intermediate was present. Using mass spectrometry and transient kinetic analysis, we demonstrated that Asp179Asn “traps” β-lactams, preferentially binding β-lactams longer than AVI owing to a decreased rate of deacylation. Molecular dynamics simulations predict that (i) the Asp179Asn variant confers more flexibility to the Ω-loop and expands the active site significantly; (ii) the catalytic nucleophile, S70, is shifted more than 1.5 Å and rotated more than 90°, altering the hydrogen bond networks; and (iii) E166 is displaced by 2 Å when complexed with ceftazidime. These analyses explain the increased hydrolytic profile of KPC-2 and suggest that the Asp179Asn substitution results in an alternative complex mechanism leading to CAZ-AVI resistance. The future design of novel β-lactams and β-lactamase inhibitors must consider the mechanistic basis of resistance of this and other threatening carbapenemases. |
format | Online Article Text |
id | pubmed-5666153 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | American Society for Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-56661532017-11-03 Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering Barnes, Melissa D. Winkler, Marisa L. Taracila, Magdalena A. Page, Malcolm G. Desarbre, Eric Kreiswirth, Barry N. Shields, Ryan K. Nguyen, Minh-Hong Clancy, Cornelius Spellberg, Brad Papp-Wallace, Krisztina M. Bonomo, Robert A. mBio Research Article The emergence of Klebsiella pneumoniae carbapenemases (KPCs), β-lactamases that inactivate “last-line” antibiotics such as imipenem, represents a major challenge to contemporary antibiotic therapies. The combination of ceftazidime (CAZ) and avibactam (AVI), a potent β-lactamase inhibitor, represents an attempt to overcome this formidable threat and to restore the efficacy of the antibiotic against Gram-negative bacteria bearing KPCs. CAZ-AVI-resistant clinical strains expressing KPC variants with substitutions in the Ω-loop are emerging. We engineered 19 KPC-2 variants bearing targeted mutations at amino acid residue Ambler position 179 in Escherichia coli and identified a unique antibiotic resistance phenotype. We focus particularly on the CAZ-AVI resistance of the clinically relevant Asp179Asn variant. Although this variant demonstrated less hydrolytic activity, we demonstrated that there was a prolonged period during which an acyl-enzyme intermediate was present. Using mass spectrometry and transient kinetic analysis, we demonstrated that Asp179Asn “traps” β-lactams, preferentially binding β-lactams longer than AVI owing to a decreased rate of deacylation. Molecular dynamics simulations predict that (i) the Asp179Asn variant confers more flexibility to the Ω-loop and expands the active site significantly; (ii) the catalytic nucleophile, S70, is shifted more than 1.5 Å and rotated more than 90°, altering the hydrogen bond networks; and (iii) E166 is displaced by 2 Å when complexed with ceftazidime. These analyses explain the increased hydrolytic profile of KPC-2 and suggest that the Asp179Asn substitution results in an alternative complex mechanism leading to CAZ-AVI resistance. The future design of novel β-lactams and β-lactamase inhibitors must consider the mechanistic basis of resistance of this and other threatening carbapenemases. American Society for Microbiology 2017-10-31 /pmc/articles/PMC5666153/ /pubmed/29089425 http://dx.doi.org/10.1128/mBio.00528-17 Text en Copyright © 2017 Barnes et al. https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Research Article Barnes, Melissa D. Winkler, Marisa L. Taracila, Magdalena A. Page, Malcolm G. Desarbre, Eric Kreiswirth, Barry N. Shields, Ryan K. Nguyen, Minh-Hong Clancy, Cornelius Spellberg, Brad Papp-Wallace, Krisztina M. Bonomo, Robert A. Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering |
title | Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering |
title_full | Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering |
title_fullStr | Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering |
title_full_unstemmed | Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering |
title_short | Klebsiella pneumoniae Carbapenemase-2 (KPC-2), Substitutions at Ambler Position Asp179, and Resistance to Ceftazidime-Avibactam: Unique Antibiotic-Resistant Phenotypes Emerge from β-Lactamase Protein Engineering |
title_sort | klebsiella pneumoniae carbapenemase-2 (kpc-2), substitutions at ambler position asp179, and resistance to ceftazidime-avibactam: unique antibiotic-resistant phenotypes emerge from β-lactamase protein engineering |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5666153/ https://www.ncbi.nlm.nih.gov/pubmed/29089425 http://dx.doi.org/10.1128/mBio.00528-17 |
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