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Medrano FJ, Hernando-Amado S, Martínez JL, Romero A. A new type of Class C β-lactamases defined by PIB-1. A metal-dependent carbapenem-hydrolyzing β-lactamase, from Pseudomonas aeruginosa: Structural and functional analysis. Int J Biol Macromol 2024; 277:134298. [PMID: 39097051 DOI: 10.1016/j.ijbiomac.2024.134298] [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: 04/03/2024] [Revised: 07/18/2024] [Accepted: 07/28/2024] [Indexed: 08/05/2024]
Abstract
Antibiotic resistance is one of most important health concerns nowadays, and β-lactamases are the most important resistance determinants. These enzymes, based on their structural and functional characteristics, are grouped in four categories (A, B, C and D). We have solved the structure of PIB-1, a Pseudomonas aeruginosa chromosomally-encoded β-lactamase, in its apo form and in complex with meropenem and zinc. These crystal structures show that it belongs to the Class C β-lactamase group, although it shows notable differences, especially in the Ω- and P2-loops, which are important for the enzymatic activity. Functional analysis showed that PIB-1 is able to degrade carbapenems but not cephalosporins, the typical substrate of Class C β-lactamases, and that its catalytic activity increases in the presence of metal ions, especially zinc. They do not bind to the active-site but they induce the formation of trimers that show an increased capacity for the degradation of the antibiotics, suggesting that this oligomer is more active than the other oligomeric species. While PIB-1 is structurally a Class C β-lactamase, the low sequence conservation, substrate profile and its metal-dependence, prompts us to position this enzyme as the founder of a new group inside the Class C β-lactamases. Consequently, its diversity might be wider than expected.
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Affiliation(s)
- Francisco Javier Medrano
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
| | - Sara Hernando-Amado
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Darwin 3, 28043 Madrid, Spain
| | - José Luis Martínez
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Darwin 3, 28043 Madrid, Spain
| | - Antonio Romero
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
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2
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Zhang S, Liao X, Ding T, Ahn J. Role of β-Lactamase Inhibitors as Potentiators in Antimicrobial Chemotherapy Targeting Gram-Negative Bacteria. Antibiotics (Basel) 2024; 13:260. [PMID: 38534695 DOI: 10.3390/antibiotics13030260] [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: 02/25/2024] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 03/28/2024] Open
Abstract
Since the discovery of penicillin, β-lactam antibiotics have commonly been used to treat bacterial infections. Unfortunately, at the same time, pathogens can develop resistance to β-lactam antibiotics such as penicillins, cephalosporins, monobactams, and carbapenems by producing β-lactamases. Therefore, a combination of β-lactam antibiotics with β-lactamase inhibitors has been a promising approach to controlling β-lactam-resistant bacteria. The discovery of novel β-lactamase inhibitors (BLIs) is essential for effectively treating antibiotic-resistant bacterial infections. Therefore, this review discusses the development of innovative inhibitors meant to enhance the activity of β-lactam antibiotics. Specifically, this review describes the classification and characteristics of different classes of β-lactamases and the synergistic mechanisms of β-lactams and BLIs. In addition, we introduce potential sources of compounds for use as novel BLIs. This provides insights into overcoming current challenges in β-lactamase-producing bacteria and designing effective treatment options in combination with BLIs.
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Affiliation(s)
- Song Zhang
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Xinyu Liao
- Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing 314100, China
| | - Tian Ding
- Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing 314100, China
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Juhee Ahn
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Republic of Korea
- Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing 314100, China
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3
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Gato E, Guijarro-Sánchez P, Alonso-García I, Pedraza-Merino R, Conde A, Lence E, Rumbo-Feal S, Peña-Escolano A, Lasarte-Monterrubio C, Blanco-Martín T, Fernández-González A, Fernández-López MDC, Maceiras R, Martínez-Guitián M, Vázquez-Ucha JC, Martínez-Martínez L, González-Bello C, Arca-Suárez J, Beceiro A, Bou G. In vitro development of imipenem/relebactam resistance in KPC-producing Klebsiella pneumoniae involves multiple mutations including OmpK36 disruption and KPC modification. Int J Antimicrob Agents 2023; 62:106935. [PMID: 37541530 DOI: 10.1016/j.ijantimicag.2023.106935] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 05/08/2023] [Accepted: 07/21/2023] [Indexed: 08/06/2023]
Abstract
OBJECTIVES In order to inform and anticipate potential strategies aimed at combating KPC-producing Klebsiella pneumoniae infections, we analysed imipenem/relebactam and ceftazidime/avibactam single-step mutant frequencies, resistance development trajectories, differentially selected resistance mechanisms and their associated fitness cost using four representative high-risk K. pneumoniae clones. METHODS Mutant frequencies and mutant preventive concentrations were determined using agar plates containing incremental concentrations of β-lactam/β-lactamase inhibitor. Resistance dynamics were determined through incubation for 7 days in 10 mL MH tubes containing incremental concentrations of each antibiotic combination up to their 64 × baseline MIC. Two colonies per strain from each experiment were characterized by antimicrobial susceptibility testing, whole genome sequencing and competitive growth assays (to determine in vitro fitness). KPC variants associated with imipenem/relebactam resistance were characterized by cloning and biochemical experiments, atomic models and molecular dynamics simulation studies. RESULTS Imipenem/relebactam prevented the emergence of single-step resistance mutants at lower concentrations than ceftazidime/avibactam. In three of the four strains evaluated, imipenem/relebactam resistance development emerged more rapidly, and in the ST512/KPC-3 clone reached higher levels compared to baseline MICs than for ceftazidime/avibactam. Lineages evolved in the presence of ceftazidime/avibactam showed KPC substitutions associated with high-level ceftazidime/avibactam resistance, increased imipenem/relebactam susceptibility and low fitness costs. Lineages that evolved in the presence of imipenem/relebactam showed OmpK36 disruption, KPC modifications (S106L, N132S, L167R) and strain-specific substitutions associated with imipenem/relebactam resistance and high fitness costs. Imipenem/relebactam-selected KPC derivatives demonstrated enhanced relebactam resistance through important changes affecting relebactam recognition and positioning. CONCLUSIONS Our findings anticipate potential resistance mechanisms affecting imipenem/relebactam during treatment of KPC-producing K. pneumoniae infections.
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Affiliation(s)
- Eva Gato
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Paula Guijarro-Sánchez
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Isaac Alonso-García
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Rosa Pedraza-Merino
- Unidad de Microbiología, Hospital Universitario Reina Sofía, Departamento de Química Agrícola, Edafología y Microbiología, Universidad de Córdoba, e Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC), España
| | - Adrian Conde
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Emilio Lence
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Soraya Rumbo-Feal
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Andrea Peña-Escolano
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Cristina Lasarte-Monterrubio
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Tania Blanco-Martín
- Unidad de Microbiología, Hospital Universitario Reina Sofía, Departamento de Química Agrícola, Edafología y Microbiología, Universidad de Córdoba, e Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC), España
| | - Ana Fernández-González
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - M Del Carmen Fernández-López
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Romina Maceiras
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain
| | - Marta Martínez-Guitián
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain; NANOBIOFAR, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Juan Carlos Vázquez-Ucha
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain; Ciber de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Luis Martínez-Martínez
- Unidad de Microbiología, Hospital Universitario Reina Sofía, Departamento de Química Agrícola, Edafología y Microbiología, Universidad de Córdoba, e Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC), España; Ciber de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Concepción González-Bello
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Jorge Arca-Suárez
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain; Ciber de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
| | - Alejandro Beceiro
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain; Ciber de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Germán Bou
- Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario, Universitario A Coruña, A Coruña, Spain; Ciber de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
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4
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Sharkady SM, Bailey B, Thompson DK. Characterization of Two Novel AmpC Beta-Lactamases from the Emerging Opportunistic Pathogen, Cedecea neteri. Antibiotics (Basel) 2023; 12:antibiotics12020219. [PMID: 36830129 PMCID: PMC9952435 DOI: 10.3390/antibiotics12020219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/06/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
The genus Cedecea (family Enterobacteriaceae) causes a wide spectrum of acute infections in immunocompromised hosts, from pneumonia and bacteremia to oral ulcers and dialysis-related peritonitis. While Cedecea infections are reported infrequently in the literature, documented clinical cases of this emerging opportunistic human pathogen have occurred worldwide. Cedecea neteri has clinical significance and exhibits antimicrobial drug resistance. However, little is known about the molecular basis underlying the resistance phenotypes in C. neteri. We previously hypothesized that the open-reading frame cnt10470 in the C. neteri SSMD04 genome encodes a chromosomal Ambler class C (AmpC) β-lactamase based on sequence homology. In this study, recombinant polyhistidine-tagged proteins were created by cloning the putative ampC genes from SSMD04 and C. neteri ATCC 33855 (a clinical isolate) into the pET-6xHN expression vector, overexpressing the proteins, and then purifying the recombinant AmpCs (rAmpCs) using immobilized metal affinity chromatography (Ni-NTA). The in vitro enzymatic analysis of the purified rAmpCs was performed to determine the Km and kcat for various β-lactam substrates. The rAmpCs are functional class C β-lactamases when assayed using the chromogenic β-lactamase substrate, nitrocefin. The presence of functional AmpCs in both C. neteri strains underscores the necessity of performing antibiotic susceptibility testing in the management of C. neteri infections.
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5
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Vázquez-Ucha JC, Rodríguez D, Lasarte-Monterrubio C, Lence E, Arca-Suarez J, Maneiro M, Gato E, Perez A, Martínez-Guitián M, Juan C, Oliver A, Bou G, González-Bello C, Beceiro A. 6-Halopyridylmethylidene Penicillin-Based Sulfones Efficiently Inactivate the Natural Resistance of Pseudomonas aeruginosa to β-Lactam Antibiotics. J Med Chem 2021; 64:6310-6328. [PMID: 33913328 DOI: 10.1021/acs.jmedchem.1c00369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pseudomonas aeruginosa, a major cause of nosocomial infections, is considered a paradigm of antimicrobial resistance, largely due to hyperproduction of chromosomal cephalosporinase AmpC. Here, we explore the ability of 6-pyridylmethylidene penicillin-based sulfones 1-3 to inactivate the AmpC β-lactamase and thus rescue the activity of the antipseudomonal ceftazidime. These compounds increased the susceptibility to ceftazidime in a collection of clinical isolates and PAO1 mutant strains with different ampC expression levels and also improved the inhibition kinetics relative to avibactam, displaying a slow deacylation rate and involving the formation of an indolizine adduct. Bromide 2 was the inhibitor with the lowest KI (15.6 nM) and the highest inhibitory efficiency (kinact/KI). Computational studies using diverse AmpC enzymes revealed that the aromatic moiety in 1-3 targets a tunnel-like site adjacent to the catalytic serine and induces the folding of the H10 helix, indicating the potential value of this not-always-evident pocket in drug design.
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Affiliation(s)
- Juan C Vázquez-Ucha
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
| | - Diana Rodríguez
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, Santiago de Compostela 15782, Spain
| | - Cristina Lasarte-Monterrubio
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
| | - Emilio Lence
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, Santiago de Compostela 15782, Spain
| | - Jorge Arca-Suarez
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
| | - María Maneiro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, Santiago de Compostela 15782, Spain
| | - Eva Gato
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
| | - Astrid Perez
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
| | - Marta Martínez-Guitián
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
| | - Carlos Juan
- Servicio de Microbiología y Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdiSBA), Carretera de Valldemossa, 79, Palma de Mallorca 07120, Spain
| | - Antonio Oliver
- Servicio de Microbiología y Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdiSBA), Carretera de Valldemossa, 79, Palma de Mallorca 07120, Spain
| | - German Bou
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
| | - Concepción González-Bello
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, Santiago de Compostela 15782, Spain
| | - Alejandro Beceiro
- Servicio de Microbiología do Complejo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (CICA-INIBIC), Xubias de Arriba, 84, A Coruña 15006, Spain
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6
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Ceftazidime-Avibactam Resistance Mediated by the N 346Y Substitution in Various AmpC β-Lactamases. Antimicrob Agents Chemother 2020; 64:AAC.02311-19. [PMID: 32253219 DOI: 10.1128/aac.02311-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 04/02/2020] [Indexed: 11/20/2022] Open
Abstract
Chromosomal and plasmid-borne AmpC cephalosporinases are a major resistance mechanism to β-lactams in Enterobacteriaceae and Pseudomonas aeruginosa The new β-lactamase inhibitor avibactam effectively inhibits class C enzymes and can fully restore ceftazidime susceptibility. The conserved amino acid residue Asn346 of AmpC cephalosporinases directly interacts with the avibactam sulfonate. Disruption of this interaction caused by the N346Y amino acid substitution in Citrobacter freundii AmpC was previously shown to confer resistance to the ceftazidime-avibactam combination (CAZ-AVI). The aim of this study was to phenotypically and biochemically characterize the consequences of the N346Y substitution in various AmpC backgrounds. Introduction of N346Y into Enterobacter cloacae AmpC (AmpCcloacae), plasmid-mediated DHA-1, and P. aeruginosa PDC-5 led to 270-, 12,000-, and 79-fold decreases in the inhibitory efficacy (k 2/Ki ) of avibactam, respectively. The kinetic parameters of AmpCcloacae and DHA-1 for ceftazidime hydrolysis were moderately affected by the substitution. Accordingly, AmpCcloacae and DHA-1 harboring N346Y conferred CAZ-AVI resistance (MIC of ceftazidime of 16 μg/ml in the presence of 4 μg/ml of avibactam). In contrast, production of PDC-5 N346Y was associated with a lower MIC (4 μg/ml) since this β-lactamase retained a higher inactivation efficacy by avibactam in comparison to AmpCcloacae N346Y. For FOX-3, the I346Y substitution did not reduce the inactivation efficacy of avibactam and the substitution was highly deleterious for β-lactam hydrolysis, including ceftazidime, preventing CAZ-AVI resistance. Since AmpCcloacae and DHA-1 display substantial sequence diversity, our results suggest that loss of hydrogen interaction between Asn346 and avibactam could be a common mechanism of acquisition of CAZ-AVI resistance.
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Gurbani D, Du G, Henning NJ, Rao S, Bera AK, Zhang T, Gray NS, Westover KD. Structure and Characterization of a Covalent Inhibitor of Src Kinase. Front Mol Biosci 2020; 7:81. [PMID: 32509799 PMCID: PMC7248381 DOI: 10.3389/fmolb.2020.00081] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/08/2020] [Indexed: 12/11/2022] Open
Abstract
Unregulated Src activity promotes malignant processes in cancer, but no Src-directed targeted therapies are used clinically, possibly because early Src inhibitors produce off-target effects leading to toxicity. Improved selective Src inhibitors may enable Src-directed therapies. Previously, we reported an irreversible Src inhibitor, DGY-06-116, based on the hybridization of dasatinib and a promiscuous covalent kinase probe SM1-71. Here, we report biochemical and biophysical characterization of this compound. An x-ray co-crystal structure of DGY-06-116: Src shows a covalent interaction with the kinase p-loop and occupancy of the back hydrophobic kinase pocket, explaining its high potency, and selectivity. However, a reversible analog also shows similar potency. Kinetic analysis shows a slow inactivation rate compared to other clinically approved covalent kinase inhibitors, consistent with a need for p-loop movement prior to covalent bond formation. Overall, these results suggest that a strong reversible interaction is required to allow sufficient time for the covalent reaction to occur. Further optimization of the covalent linker may improve the kinetics of covalent bond formation.
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Affiliation(s)
- Deepak Gurbani
- Departments of Biochemistry and Radiation Oncology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, United States
| | - Guangyan Du
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA, United States
| | - Nathaniel J. Henning
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA, United States
| | - Suman Rao
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA, United States
- Harvard Program in Therapeutic Science (HiTS), Harvard Medical School, Boston, MA, United States
| | - Asim K. Bera
- Departments of Biochemistry and Radiation Oncology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, United States
| | - Tinghu Zhang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA, United States
| | - Nathanael S. Gray
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA, United States
| | - Kenneth D. Westover
- Departments of Biochemistry and Radiation Oncology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, United States
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8
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Rodríguez D, Maneiro M, Vázquez-Ucha JC, Beceiro A, González-Bello C. 6-Arylmethylidene Penicillin-Based Sulfone Inhibitors for Repurposing Antibiotic Efficiency in Priority Pathogens. J Med Chem 2020; 63:3737-3755. [PMID: 32196336 DOI: 10.1021/acs.jmedchem.0c00127] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of 6-(aryl)methylidene penicillin-based sulfones 1-7 to repurpose β-lactam antibiotics activity with bacterial species that carry carbapenem-hydrolyzing class D β-lactamases (OXA-23, OXA-24/40 and OXA-48), as well as with class A (TEM-1, CTX-M-2) and class C (CMY-2, DHA-1) enzymes, is reported. The combinations imipenem/3 and imipenem/4 restored almost completely the antibiotic efficacy in OXA-23 and OXA-24/40 carbapenemase-producing A. baumannii strains (1 μg mL-1) and also provided good results for OXA-48 carbapenemase-producing K. pneumoniae strains (4 μg mL-1). Compounds 2-6 in combinations with ceftazidime and ampicillin were also efficient in restoring antibiotic efficacy in E. coli strains carrying class C (CMY-2 and DHA-1) and class A (TEM-1 and CTX-M-2) β-lactamase enzymes, respectively. Kinetic and inhibition studies with the OXA-24/40 enzyme, protein mass spectrometry analysis and docking studies allowed us to gain an insight into the inhibition mechanism and the experimentally observed differences between the ligands.
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Affiliation(s)
- Diana Rodríguez
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, 15782 Santiago de Compostela, Spain
| | - María Maneiro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, 15782 Santiago de Compostela, Spain
| | - Juan C Vázquez-Ucha
- Servicio de Microbiología do Complexo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (INIBIC), Xubias de Arriba, 84, 15006 A Coruña, Spain
| | - Alejandro Beceiro
- Servicio de Microbiología do Complexo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (INIBIC), Xubias de Arriba, 84, 15006 A Coruña, Spain
| | - Concepción González-Bello
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, 15782 Santiago de Compostela, Spain
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Girlich D, Bonnin RA, Dortet L, Naas T. Genetics of Acquired Antibiotic Resistance Genes in Proteus spp. Front Microbiol 2020; 11:256. [PMID: 32153540 PMCID: PMC7046756 DOI: 10.3389/fmicb.2020.00256] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/03/2020] [Indexed: 01/30/2023] Open
Abstract
Proteus spp. are commensal Enterobacterales of the human digestive tract. At the same time, P. mirabilis is commonly involved in urinary tract infections (UTI). P. mirabilis is naturally resistant to several antibiotics including colistin and shows reduced susceptibility to imipenem. However higher levels of resistance to imipenem commonly occur in P. mirabilis isolates consecutively to the loss of porins, reduced expression of penicillin binding proteins (PBPs) PBP1a, PBP2, or acquisition of several antibiotic resistance genes, including carbapenemase genes. In addition, resistance to non-β-lactams is also frequently reported including molecules used for treating UTI infections (e.g., fluoroquinolones, nitrofurans). Emergence and spread of multidrug resistant P. mirabilis isolates, including those producing ESBLs, AmpC cephalosporinases and carbapenemases, are being more and more frequently reported. This review covers Proteus spp. with a focus on the different genetic mechanisms involved in the acquisition of resistance genes to multiple antibiotic classes turning P. mirabilis into a dreadful pandrug resistant bacteria and resulting in difficult to treat infections.
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Affiliation(s)
- Delphine Girlich
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
| | - Rémy A Bonnin
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
| | - Laurent Dortet
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
| | - Thierry Naas
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
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10
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Acquisition of Extended-Spectrum β-Lactamase GES-6 Leading to Resistance to Ceftolozane-Tazobactam Combination in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2018; 63:AAC.01809-18. [PMID: 30323045 DOI: 10.1128/aac.01809-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 10/11/2018] [Indexed: 12/21/2022] Open
Abstract
A clinical Pseudomonas aeruginosa isolate resistant to all β-lactams, including ceftolozane-tazobactam and carbapenems, was recovered. It belonged to sequence type 235 and produced the extended-spectrum β-lactamase (ESBL) GES-6 differing from GES-1 by two amino acid substitutions (E104K and G170S). GES-6 possessed an increased hydrolytic activity toward carbapenems and to ceftolozane and a decreased susceptibility to β-lactamase inhibitors compared to GES-1, except for avibactam. We show here that resistance to ceftolozane-tazobactam may occur through acquisition of a specific ESBL in P. aeruginosa but that ceftazidime-avibactam combination remains an effective alternative.
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11
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Pérez-Llarena FJ, Vázquez-Ucha JC, Kerff F, Zamorano L, Miró E, Cabral MP, Fleites A, Lantero M, Martínez-Martínez L, Oliver A, Galleni M, Navarro F, Beceiro A, Bou G. Increased Antimicrobial Resistance in a Novel CMY-54 AmpC-Type Enzyme with a GluLeu217–218 Insertion in the Ω-Loop. Microb Drug Resist 2018; 24:527-533. [DOI: 10.1089/mdr.2017.0017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | - Frédéric Kerff
- Centre d'Ingénierie des Protéines, Université de Liège, Liège, Belgium
| | - Laura Zamorano
- Servicio de Microbiología, Hospital Universitario Son Espases, Palma de Mallorca, Spain
| | - Elisenda Miró
- Servicio de Microbiología, Hospital de la Santa Creu i Sant Pau/IIB-Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - María Póvoa Cabral
- Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
| | - Ana Fleites
- Servicio de Microbiología, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Marta Lantero
- Servicio de Microbiología, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Luis Martínez-Martínez
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla-IDIVAL, Santander, Spain
- Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Universitario Son Espases, Palma de Mallorca, Spain
| | - Moreno Galleni
- Centre d'Ingénierie des Protéines, Université de Liège, Liège, Belgium
| | - Ferrán Navarro
- Servicio de Microbiología, Hospital de la Santa Creu i Sant Pau/IIB-Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Alejandro Beceiro
- Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
| | - Germán Bou
- Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
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12
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Decuyper L, Jukič M, Sosič I, Žula A, D'hooghe M, Gobec S. Antibacterial and β-Lactamase Inhibitory Activity of Monocyclic β-Lactams. Med Res Rev 2017; 38:426-503. [DOI: 10.1002/med.21443] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/16/2017] [Accepted: 02/08/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Lena Decuyper
- SynBioC Research Group, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering; Ghent University; Ghent Belgium
| | - Marko Jukič
- Faculty of Pharmacy; University of Ljubljana; Ljubljana Slovenia
| | - Izidor Sosič
- Faculty of Pharmacy; University of Ljubljana; Ljubljana Slovenia
| | - Aleš Žula
- Faculty of Pharmacy; University of Ljubljana; Ljubljana Slovenia
| | - Matthias D'hooghe
- SynBioC Research Group, Department of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering; Ghent University; Ghent Belgium
| | - Stanislav Gobec
- Faculty of Pharmacy; University of Ljubljana; Ljubljana Slovenia
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13
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Khoshnood S, Heidary M, Mirnejad R, Bahramian A, Sedighi M, Mirzaei H. Drug-resistant gram-negative uropathogens: A review. Biomed Pharmacother 2017; 94:982-994. [PMID: 28810536 DOI: 10.1016/j.biopha.2017.08.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 07/31/2017] [Accepted: 08/02/2017] [Indexed: 12/27/2022] Open
Abstract
Urinary tract infection(UTI) caused by Gram-negative bacteria is the second most common infectious presentation in community medical practice. Approximately 150 million people are diagnosed with UTI each year worldwide. Drug resistance in Gram-negative uropathogens is a major global concern which can lead to poor clinical outcomes including treatment failure, development of bacteremia, requirement for intravenous therapy, hospitalization, and extended length of hospital stay. The mechanisms of drug resistance in these bacteria are important due to they are often not identified by routine susceptibility tests and have an exceptional potential for outbreaks. Treatment of UTIs depends on the access to effective drugs, which is now threatened by antibiotic resistant Gram-negative uropathogens. Although several effective antibiotics with activity against highly resistant Gram-negatives are available, there is not a unique antibiotic with activity against the high variety of resistance. Therefore, antimicrobial susceptibility tests, correlation between clinicians and laboratories, development of more rapid diagnostic methods, and continuous monitoring of drug resistance are urgent priorities. In this review, we will discuss about the current global status of drug-resistant Gram-negative uropathogens and their mechanisms of drug resistance to provide new insights into their treatment options.
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Affiliation(s)
- Saeed Khoshnood
- Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohsen Heidary
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Reza Mirnejad
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Aghil Bahramian
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mansour Sedighi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Habibollah Mirzaei
- Department of Virology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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Abstract
Given the serious medical burden of β-lactamases, many approaches are being used identify candidate agents for β-lactamase inhibition. Here, we review two β-lactam-β-lactamase inhibitor (BL-BLI) combinations, ceftolozane-tazobactam and ceftazidime-avibactam that recently entered the clinic. In addition, we focus on BL-BLI combinations in preclinical development that have demonstrated activity in clinical isolates via susceptibility testing and/or in in vivo models of infection. We highlight only the BLIs that are able to reduce the Clinical Laboratory Standards Institute (CLSI) breakpoints for the BL partner into the susceptible range. Our analysis includes the primary literature, meeting abstracts, as well as the patent literature.
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15
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Vorberg R, Trapp N, Carreira EM, Müller K. Bicyclo[3.2.0]heptane as a Core Structure for Conformational Locking of 1,3-Bis-Pharmacophores, Exemplified by GABA. Chemistry 2017; 23:3126-3138. [DOI: 10.1002/chem.201605179] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Indexed: 01/26/2023]
Affiliation(s)
- Raffael Vorberg
- Laboratorium für Organische Chemie; ETH Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Nils Trapp
- Laboratorium für Organische Chemie; ETH Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Erick M. Carreira
- Laboratorium für Organische Chemie; ETH Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Klaus Müller
- Laboratorium für Organische Chemie; ETH Zürich; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
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16
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Vallejo JA, Martínez-Guitián M, Vázquez-Ucha JC, González-Bello C, Poza M, Buynak JD, Bethel CR, Bonomo RA, Bou G, Beceiro A. LN-1-255, a penicillanic acid sulfone able to inhibit the class D carbapenemase OXA-48. J Antimicrob Chemother 2016; 71:2171-80. [PMID: 27125555 DOI: 10.1093/jac/dkw105] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/04/2016] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES Carbapenemases are the most important mechanism responsible for carbapenem resistance in Enterobacteriaceae. Among carbapenemases, OXA-48 presents unique challenges as it is resistant to β-lactam inhibitors. Here, we test the capacity of the compound LN-1-255, a 6-alkylidene-2'-substituted penicillanic acid sulfone, to inhibit the activity of the carbapenemase OXA-48. METHODS The OXA-48 gene was cloned and expressed in Klebsiella pneumoniae and Escherichia coli in order to obtain MICs in the presence of inhibitors (clavulanic acid, tazobactam and sulbactam) and LN-1-255. OXA-48 was purified and steady-state kinetics was performed with LN-1-255 and tazobactam. The covalent binding mode of LN-1-255 with OXA-48 was studied by docking assays. RESULTS Both OXA-48-producing clinical and transformant strains displayed increased susceptibility to carbapenem antibiotics in the presence of 4 mg/L LN-1-255 (2-32-fold increased susceptibility) and 16 mg/L LN-1-255 (4-64-fold increased susceptibility). Kinetic assays demonstrated that LN-1-255 is able to inhibit OXA-48 with an acylation efficiency (k2/K) of 10 ± 1 × 10(4) M(-1) s(-1) and a slow deacylation rate (koff) of 7 ± 1 × 10(-4) s(-1). IC50 was 3 nM for LN-1-255 and 1.5 μM for tazobactam. Lastly, kcat/kinact was 500-fold lower for LN-1-255 than for tazobactam. CONCLUSIONS In these studies, carbapenem antibiotics used in combination with LN-1-255 are effective against the carbapenemase OXA-48, an important emerging mechanism of antibiotic resistance. This provides an incentive for further investigations to maximize the efficacy of penicillin sulfone inhibition of class D plasmid-carried Enterobacteriaceae carbapenemases.
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Affiliation(s)
- Juan A Vallejo
- Servicio de Microbiología-Instituto de Investigación Biomédica (INIBIC), 15006 A Coruña, Spain
| | - Marta Martínez-Guitián
- Servicio de Microbiología-Instituto de Investigación Biomédica (INIBIC), 15006 A Coruña, Spain
| | - Juan C Vázquez-Ucha
- Servicio de Microbiología-Instituto de Investigación Biomédica (INIBIC), 15006 A Coruña, Spain
| | - Concepción González-Bello
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Margarita Poza
- Servicio de Microbiología-Instituto de Investigación Biomédica (INIBIC), 15006 A Coruña, Spain
| | - John D Buynak
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275, USA
| | - Christopher R Bethel
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Robert A Bonomo
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA Departments of Biochemistry, Molecular Biology and Microbiology, Pharmacology and Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - German Bou
- Servicio de Microbiología-Instituto de Investigación Biomédica (INIBIC), 15006 A Coruña, Spain
| | - Alejandro Beceiro
- Servicio de Microbiología-Instituto de Investigación Biomédica (INIBIC), 15006 A Coruña, Spain
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17
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Zhang SJ, Sun WW, Cao P, Dong XP, Liu JK, Wu B. Stereoselective Synthesis of Diazabicyclic β-Lactams through Intramolecular Amination of Unactivated C(sp3)–H Bonds of Carboxamides by Palladium Catalysis. J Org Chem 2016; 81:956-68. [PMID: 26745308 DOI: 10.1021/acs.joc.5b02532] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Shi-Jin Zhang
- Pharmacy
College, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- State
Key Laboratory of Phytochemistry and Plant Resources in West China,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Wen-Wu Sun
- State
Key Laboratory of Phytochemistry and Plant Resources in West China,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pei Cao
- State
Key Laboratory of Phytochemistry and Plant Resources in West China,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Xiao-Ping Dong
- Pharmacy
College, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Ji-Kai Liu
- School
of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, China
| | - Bin Wu
- State
Key Laboratory of Phytochemistry and Plant Resources in West China,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- School
of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, China
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18
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Kinetics of the Interaction between BAL29880 and LK157 and the Class C β-Lactamase CHE-1. Antimicrob Agents Chemother 2016; 60:1747-50. [PMID: 26729500 DOI: 10.1128/aac.02062-15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/27/2015] [Indexed: 11/20/2022] Open
Abstract
The chromosome-encoded class C β-lactamase CHE-1 produced by Enterobacter cloacae exhibits a lower sensitivity to avibactam than the P99 enzyme from which it is derived by a 6-residue deletion in the H-10 helix. In the present study, we investigated the sensitivity of CHE-1 to two other β-lactamase inhibitors: LK-157 (or Lek 157), a tricyclic β-lactam, and BAL29880, a bridged monobactam. With both compounds, the second-order rate constants for inactivation were significantly lower for CHE-1, which can thus be considered an inactivator-resistant mutant of P99. However, the second-order rate constant for the inactivation by BAL29880 probably remains adequate for a rather rapid reaction with CHE-1 in the absence of protection by the substrate.
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19
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Analysis of the Structure and Function of FOX-4 Cephamycinase. Antimicrob Agents Chemother 2015; 60:717-28. [PMID: 26525784 DOI: 10.1128/aac.01887-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/14/2015] [Indexed: 12/21/2022] Open
Abstract
Class C β-lactamases poorly hydrolyze cephamycins (e.g., cefoxitin, cefotetan, and moxalactam). In the past 2 decades, a new family of plasmid-based AmpC β-lactamases conferring resistance to cefoxitin, the FOX family, has grown to include nine unique members descended from the Aeromonas caviae chromosomal AmpC. To understand the basis for the unique cephamycinase activity in the FOX family, we determined the first X-ray crystal structures of FOX-4, apo enzyme and the acyl-enzyme with its namesake compound, cefoxitin, using the Y150F deacylation-deficient variant. Notably, recombinant expression of N-terminally tagged FOX-4 also yielded an inactive adenylylated enzyme form not previously observed in β-lactamases. The posttranslational modification (PTM), which occurs on the active site Ser64, would not seem to provide a selective advantage, yet might present an opportunity for the design of novel antibacterial drugs. Substantial ligand-induced changes in the enzyme are seen in the acyl-enzyme complex, particularly the R2 loop and helix H10 (P289 to N297), with movement of F293 by 10.3 Å. Taken together, this study provides the first picture of this highly proficient class C cephamycinase, uncovers a novel PTM, and suggests a possible cephamycin resistance mechanism involving repositioning of the substrate due to the presence of S153P, N289P, and N346I substitutions in the ligand binding pocket.
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20
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In Vivo Evolution of CMY-2 to CMY-33 β-Lactamase in Escherichia coli Sequence Type 131: Characterization of an Acquired Extended-Spectrum AmpC Conferring Resistance to Cefepime. Antimicrob Agents Chemother 2015; 59:7483-8. [PMID: 26392491 DOI: 10.1128/aac.01804-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 09/13/2015] [Indexed: 11/20/2022] Open
Abstract
Cefepime is frequently prescribed to treat infections caused by AmpC-producing Gram-negative bacteria. CMY-2 is the most common plasmid-mediated AmpC (pAmpC) β-lactamase. Unfortunately, CMY variants conferring enhanced cefepime resistance have been reported. Here, we describe the evolution of CMY-2 to an extended-spectrum AmpC (ESAC) in clonally identical Escherichia coli isolates obtained from a patient. The CMY-2-producing E. coli isolate (CMY-2-Ec) was isolated from a wound. Thirty days later, one CMY-33-producing E. coli isolate (CMY-33-Ec) was detected in a bronchoalveolar lavage fluid sample. Two weeks before the isolation of CMY-33-Ec, the patient received cefepime. CMY-33-Ec and CMY-2-Ec were identical by repetitive extragenic palindromic-PCR (rep-PCR), being of hyperepidemic sequence type 131 (ST131) but showing different β-lactam MICs (e.g., cefepime MIC, 16 and ≤ 0.5 μg/ml for CMY-33-Ec and CMY-2-Ec, respectively). Identical CMY-2-Ec isolates were also found in a rectal swab. CMY-33 differs from CMY-2 by a Leu293-Ala294 deletion. Expressed in E. coli strain DH10B, both CMYs conferred resistance to ceftazidime (≥ 256 μg/ml), but the cefepime MICs were higher for CMY-33 than CMY-2 (8 versus 0.25 μg/ml, respectively). The kcat/Km or inhibitor complex inactivation (kinact)/Ki app (μM(-1) s(-1)) indicated that CMY-33 possesses an extended-spectrum β-lactamase (ESBL)-like spectrum compared to that of CMY-2 (e.g., cefoxitin, 0.2 versus 0.4; ceftazidime, 0.2 versus not measurable; cefepime, 0.2 versus not measurable; and tazobactam, 0.0018 versus 0.0009, respectively). Using molecular modeling, we show that a widened active site (∼ 4-Å shift) may play a significant role in enhancing cefepime hydrolysis. This is the first in vivo demonstration of a pAmpC that under cephalosporin treatment expands its substrate spectrum, resembling an ESBL. The prevalence of CMY-2-Ec isolates is rapidly increasing worldwide; therefore, awareness that cefepime treatment may select for resistant isolates is critical.
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