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McLeod SM, Carter NM, Huband MD, Traczewski MM, Bradford PA, Miller AA. Sulbactam-durlobactam susceptibility test method development and quality control ranges for MIC and disk diffusion tests. J Clin Microbiol 2024; 62:e0122823. [PMID: 38095417 PMCID: PMC10793306 DOI: 10.1128/jcm.01228-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/06/2023] [Indexed: 01/18/2024] Open
Abstract
Sulbactam-durlobactam is a β-lactam/β-lactamase inhibitor combination developed to treat hospital-acquired and ventilator-associated bacterial pneumonia caused by Acinetobacter baumannii-calcoaceticus complex (ABC). Durlobactam is a diazabicyclooctane β-lactamase inhibitor with potent activity against Ambler classes A, C, and D serine β-lactamases and restores sulbactam activity against multidrug-resistant ABC. Studies were conducted to establish sulbactam-durlobactam antimicrobial susceptibility testing methods for both broth microdilution minimal inhibitory concentration (MIC) and disk diffusion tests as well as quality control (QC) ranges. To establish the MIC test method, combinations of sulbactam and durlobactam were evaluated using a panel of genetically characterized A. baumannii isolates which were categorized as predicted to be susceptible or resistant based on the spectrum of β-lactamase inhibition by durlobactam. MIC testing with doubling dilutions of sulbactam with a fixed concentration of 4 µg/mL of durlobactam resulted in the greatest discrimination of the pre-defined susceptible and resistant strains. Similarly, the sulbactam/durlobactam 10/10 µg disk concentration showed the best discrimination as well as correlation with the MIC test. A. baumannii NCTC 13304 was selected for QC purposes because it assesses the activity of both sulbactam and durlobactam with clear endpoints. Multi-laboratory QC studies were conducted according to CLSI M23 Tier 2 criteria. A sulbactam-durlobactam broth MIC QC range of 0.5/4-2/4 µg/mL and a zone diameter QC range of 24-30 mm were determined for A. baumannii NCTC 13304 and have been approved by CLSI. These studies will enable clinical laboratories to perform susceptibility tests with accurate and reproducible methods.
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Affiliation(s)
- Sarah M. McLeod
- Entasis Therapeutics Inc. (an affiliate of Innoviva Specialty Therapeutics, Inc.), Waltham, Massachusetts, USA
| | - Nicole M. Carter
- Entasis Therapeutics Inc. (an affiliate of Innoviva Specialty Therapeutics, Inc.), Waltham, Massachusetts, USA
| | | | | | | | - Alita A. Miller
- Entasis Therapeutics Inc. (an affiliate of Innoviva Specialty Therapeutics, Inc.), Waltham, Massachusetts, USA
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Hussein M, Allobawi R, Zhao J, Yu H, Neville SL, Wilksch J, Wong LJM, Baker M, McDevitt CA, Rao GG, Li J, Velkov T. Integrated Transcriptomic and Metabolomic Mapping Reveals the Mechanism of Action of Ceftazidime/Avibactam against Pan-Drug-Resistant Klebsiella pneumoniae. ACS Infect Dis 2023; 9:2409-2422. [PMID: 37878861 PMCID: PMC10714405 DOI: 10.1021/acsinfecdis.3c00264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/02/2023] [Accepted: 10/11/2023] [Indexed: 10/27/2023]
Abstract
Here, we employed an integrated metabolomics and transcriptomics approach to investigate the molecular mechanism(s) of action of ceftazidime/avibactam against a pan-drug-resistant K. pneumoniae clinical isolate from a patient with urinary tract infection. Ceftazidime/avibactam induced time-dependent perturbations in the metabolome and transcriptome of the bacterium, mainly at 6 h, with minimal effects at 1 and 3 h. Metabolomics analysis revealed a notable reduction in essential lipids involved in outer membrane glycerolipid biogenesis. This disruption effect extended to peptidoglycan and lipopolysaccharide biosynthetic pathways, including lipid A and O-antigen assembly. Importantly, ceftazidime/avibactam not only affected the final steps of peptidoglycan biosynthesis in the periplasm, a common mechanism of ceftazidime action, but also influenced the synthesis of lipid-linked intermediates and early stages of cytoplasmic peptidoglycan synthesis. Furthermore, ceftazidime/avibactam substantially inhibited central carbon metabolism (e.g., the pentose phosphate pathway and tricarboxylic acid cycle). Consistently, the dysregulation of genes governing these metabolic pathways aligned with the metabolomics findings. Certain metabolomics and transcriptomics signatures associated with ceftazidime resistance were also perturbed. Consistent with the primary target of antibiotic activity, biochemical assays also confirmed the direct impact of ceftazidime/avibactam on peptidoglycan production. This study explored the intricate interactions of ceftazidime and avibactam within bacterial cells, including their impact on cell envelope biogenesis and central carbon metabolism. Our findings revealed the complexities of how ceftazidime/avibactam operates, such as hindering peptidoglycan formation in different cellular compartments. In summary, this study confirms the existing hypotheses about the antibacterial and resistance mechanisms of ceftazidime/avibactam while uncovering novel insights, including its impact on lipopolysaccharide formation.
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Affiliation(s)
- Maytham Hussein
- Monash
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Rafah Allobawi
- Monash
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Jinxin Zhao
- Monash
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Heidi Yu
- Monash
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Stephanie L. Neville
- Department
of Microbiology and Immunology, The Peter Doherty Institute for Infection
and Immunity, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Jonathan Wilksch
- Department
of Microbiology and Immunology, The Peter Doherty Institute for Infection
and Immunity, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Labell J. M. Wong
- Monash
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Mark Baker
- Discipline
of Biological Sciences, Priority Research Centre in Reproductive Biology,
Faculty of Science and IT, University of
Newcastle, University
Drive, Callaghan, NSW 2308, Australia
| | - Christopher A. McDevitt
- Department
of Microbiology and Immunology, The Peter Doherty Institute for Infection
and Immunity, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Gauri G. Rao
- Division
of Pharmacotherapy and Experimental Therapeutics, Eshelman School
of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599-7355, United
States
| | - Jian Li
- Monash
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Tony Velkov
- Monash
Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
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Tamma PD, Harris PNA, Mathers AJ, Wenzler E, Humphries RM. Breaking Down the Breakpoints: Rationale for the 2022 Clinical and Laboratory Standards Institute Revised Piperacillin-Tazobactam Breakpoints Against Enterobacterales. Clin Infect Dis 2023; 77:1585-1590. [PMID: 36001445 DOI: 10.1093/cid/ciac688] [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: 06/20/2022] [Revised: 08/11/2022] [Accepted: 08/22/2022] [Indexed: 11/14/2022] Open
Abstract
Piperacillin-tazobactam (PTZ) is one of the most common antibiotics administered to hospitalized patients. Its broad activity against gram-negative, gram-positive, and anaerobic pathogens; efficacy in clinical trials across diverse infection types and patient populations; and generally favorable toxicity profile make it a particularly appealing antibiotic agent. PTZ susceptibility interpretive criteria (ie, breakpoints) for the Enterobacterales were initially established in 1992, as the drug was undergoing approval by the US Food and Drug Administration. In the ensuing 30 years, changes in the molecular epidemiology of the Enterobacterales and its impact on PTZ susceptibility testing, mounting pharmacokinetic/pharmacodynamic data generated from sophisticated techniques such as population pharmacokinetic modeling and Monte Carlo simulation, and disturbing safety signals in a large clinical trial prompted the Clinical Laboratory and Standards Institute (CLSI) to review available evidence to determine the need for revision of the PTZ breakpoints for Enterobacterales. After an extensive literature review and formal voting process, the susceptibility criteria were revised in the 2022 CLSI M100 document to the following: ≤8/4 µg/mL (susceptible), 16/4 µg/mL (susceptible dose-dependent), and ≥32/4 µg/mL (resistant). Herein, we provide a brief overview of the CLSI process of antibiotic breakpoint revisions and elaborate on the available data that ultimately led to the decision to revise the PTZ breakpoints.
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Affiliation(s)
- Pranita D Tamma
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Patrick N A Harris
- Faculty of Medicine, UQ Center for Clinical Research, Royal Brisbane and Women's Hospital Campus, University of Queensland, Brisbane, Australia
| | - Amy J Mathers
- Department of Medicine and Pathology, University of Virginia, Charlottesville, Virginia, USA
| | - Eric Wenzler
- Department of Pharmacy Practice, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Romney M Humphries
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Tam VH, Merlau PR, Hudson CS, Kline EG, Eales BM, Smith J, Sofjan AK, Shields RK. Optimal ceftazidime/avibactam dosing exposure against KPC-producing Klebsiella pneumoniae. J Antimicrob Chemother 2022; 77:3130-3137. [PMID: 36031868 PMCID: PMC10205629 DOI: 10.1093/jac/dkac294] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/05/2022] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES Infections due to carbapenem-resistant Enterobacterales are considered urgent public health threats and often treated with a β-lactam/β-lactamase inhibitor combination. However, clinical treatment failure and resistance emergence have been attributed to inadequate dosing. We used a novel framework to provide insights of optimal dosing exposure of ceftazidime/avibactam. METHODS Seven clinical isolates of Klebsiella pneumoniae producing different KPC variants were examined. Ceftazidime susceptibility (MIC) was determined by broth dilution using escalating concentrations of avibactam. The observed MICs were characterized as response to avibactam concentrations using an inhibitory sigmoid Emax model. Using the best-fit parameter values, %fT>MICi was estimated for various dosing regimens of ceftazidime/avibactam. A hollow-fibre infection model (HFIM) was subsequently used to ascertain the effectiveness of selected regimens over 120 h. The drug exposure threshold associated with bacterial suppression was identified by recursive partitioning. RESULTS In all scenarios, ceftazidime MIC reductions were well characterized with increasing avibactam concentrations. In HFIM, bacterial regrowth over time correlated with emergence of resistance. Overall, suppression of bacterial regrowth was associated with %fT>MICi ≥ 76.1% (100% versus 18.2%; P < 0.001). Using our framework, the optimal drug exposure could be achieved with ceftazidime/avibactam 2.5 g every 12 h in 5 out of 7 isolates. Furthermore, ceftazidime/avibactam 2.5 g every 8 h can suppress an isolate deemed resistant based on conventional susceptibility testing method. CONCLUSIONS An optimal drug exposure to suppress KPC-producing bacteria was identified. The novel framework is informative and may be used to guide optimal dosing of other β-lactam/β-lactamase inhibitor combinations. Further in vivo investigations are warranted.
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Affiliation(s)
- Vincent H Tam
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Paul R Merlau
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Cole S Hudson
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Ellen G Kline
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Brianna M Eales
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - James Smith
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Amelia K Sofjan
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Ryan K Shields
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Dingle TC, Pitout J. The Ins and Outs of Susceptibility Testing for New β-Lactam/β-Lactamase Inhibitor Combinations for Gram-Negative Organisms. J Clin Microbiol 2022; 60:e0080721. [PMID: 35387484 PMCID: PMC9297814 DOI: 10.1128/jcm.00807-21] [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] [Indexed: 11/20/2022] Open
Abstract
Ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-relebactam are among the newest β-lactam/β-lactamase inhibitors (BL/BLIs) introduced to the North American antibiotic market. All have broad Gram-negative activity, including against certain carbapenemases. Despite this, susceptibility testing is warranted due to variable activity against certain β-lactamases (e.g., oxacillinases) and the presence of acquired resistance mechanisms in some isolates. Here, we discuss what we know about these new antimicrobial agents and how to navigate implementation of susceptibility testing and reporting of these agents in clinical laboratories.
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Affiliation(s)
- Tanis C. Dingle
- Alberta Precision Laboratories, Calgary, Alberta, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Johann Pitout
- Alberta Precision Laboratories, Calgary, Alberta, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Medical Microbiology, University of Pretoria, Pretoria, South Africa
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Selection of the Appropriate Avibactam Concentration for Use with Ceftibuten in Broth Microdilution Susceptibility Testing. Diagn Microbiol Infect Dis 2022; 103:115673. [DOI: 10.1016/j.diagmicrobio.2022.115673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/27/2022] [Accepted: 03/03/2022] [Indexed: 11/18/2022]
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Sigmoid Emax Modeling To Define the Fixed Concentration of Enmetazobactam for MIC Testing in Combination with Cefepime. Antimicrob Agents Chemother 2021; 65:e0092621. [PMID: 34097479 DOI: 10.1128/aac.00926-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The use of carbapenem antibiotics to treat infections caused by Enterobacterales expressing increasingly aggressive extended-spectrum β-lactamases (ESBLs) has contributed to the emergence of carbapenem resistance. Enmetazobactam is a novel ESBL inhibitor being developed in combination with cefepime as a carbapenem-sparing option for infections caused by ESBL-producing Enterobacterales. Cefepime-enmetazobactam checkerboard MIC profiles were obtained for a challenge panel of cefepime-resistant ESBL-producing clinical isolates of Klebsiella pneumoniae. Sigmoid maximum effect (Emax) modeling described cefepime MICs as a function of enmetazobactam concentration with no bias. A concentration of 8 μg/ml enmetazobactam proved sufficient to restore >95% of cefepime antibacterial activity in vitro against >95% of isolates tested. These results support a fixed concentration of 8 μg/ml of enmetazobactam for MIC testing.
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Davies DT, Leiris S, Zalacain M, Sprynski N, Castandet J, Bousquet J, Lozano C, Llanos A, Alibaud L, Vasa S, Pattipati R, Valige R, Kummari B, Pothukanuri S, De Piano C, Morrissey I, Holden K, Warn P, Marcoccia F, Benvenuti M, Pozzi C, Tassone G, Mangani S, Docquier JD, Pallin D, Elliot R, Lemonnier M, Everett M. Discovery of ANT3310, a Novel Broad-Spectrum Serine β-Lactamase Inhibitor of the Diazabicyclooctane Class, Which Strongly Potentiates Meropenem Activity against Carbapenem-Resistant Enterobacterales and Acinetobacter baumannii. J Med Chem 2020; 63:15802-15820. [DOI: 10.1021/acs.jmedchem.0c01535] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- David T. Davies
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | - Simon Leiris
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | | | - Nicolas Sprynski
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | - Jérôme Castandet
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | - Justine Bousquet
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | - Clarisse Lozano
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | - Agustina Llanos
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | | | - Srinivas Vasa
- GVK Biosciences Pvt. Ltd., Survey No. 125
and 126, IDA, Mallapur, Hyderabad, Telangana 500 076, India
| | - Ramesh Pattipati
- GVK Biosciences Pvt. Ltd., Survey No. 125
and 126, IDA, Mallapur, Hyderabad, Telangana 500 076, India
| | - Ravindar Valige
- GVK Biosciences Pvt. Ltd., Survey No. 125
and 126, IDA, Mallapur, Hyderabad, Telangana 500 076, India
| | - Bhaskar Kummari
- GVK Biosciences Pvt. Ltd., Survey No. 125
and 126, IDA, Mallapur, Hyderabad, Telangana 500 076, India
| | - Srinivasu Pothukanuri
- GVK Biosciences Pvt. Ltd., Survey No. 125
and 126, IDA, Mallapur, Hyderabad, Telangana 500 076, India
| | - Cyntia De Piano
- International Health Management Associates (IHMA), Rte. De I’Ile-au-Bois 1A, 1870 Monthey, Switzerland
| | - Ian Morrissey
- International Health Management Associates (IHMA), Rte. De I’Ile-au-Bois 1A, 1870 Monthey, Switzerland
| | - Kirsty Holden
- Evotec (UK) Ltd., Block 23, Alderley Park, Macclesfield, Cheshire SK10 4TG, U.K
| | - Peter Warn
- Evotec (UK) Ltd., Block 23, Alderley Park, Macclesfield, Cheshire SK10 4TG, U.K
| | - Francesca Marcoccia
- Dipartimento di Biotecnologie Mediche, University of Siena, Viale Bracci 16, Siena 53100, Italy
| | - Manuela Benvenuti
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, Siena 53100, Italy
| | - Cecilia Pozzi
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, Siena 53100, Italy
| | - Giusy Tassone
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, Siena 53100, Italy
| | - Stefano Mangani
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, Siena 53100, Italy
| | - Jean-Denis Docquier
- Dipartimento di Biotecnologie Mediche, University of Siena, Viale Bracci 16, Siena 53100, Italy
| | - David Pallin
- Charles River Laboratories, 8-9 The Spire Green Centre, Harlow, Essex CM19 5TR, U.K
| | - Richard Elliot
- Charles River Laboratories, 8-9 The Spire Green Centre, Harlow, Essex CM19 5TR, U.K
| | - Marc Lemonnier
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
| | - Martin Everett
- Antabio SAS, 436 rue Pierre et Marie Curie, 31670 Labège, France
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Antimicrobial Activity of Aztreonam-Avibactam and Comparator Agents When Tested against a Large Collection of Contemporary Stenotrophomonas maltophilia Isolates from Medical Centers Worldwide. Antimicrob Agents Chemother 2020; 64:AAC.01433-20. [PMID: 32900683 DOI: 10.1128/aac.01433-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/31/2020] [Indexed: 02/06/2023] Open
Abstract
Aztreonam-avibactam was tested against 1,839 Stenotrophomonas maltophilia isolates collected worldwide and demonstrated potent activity against isolates from all geographic regions and infection types (overall MIC50/90, 4/4 mg/liter; 97.8% inhibited at ≤8 mg/liter). Trimethoprim-sulfamethoxazole (TMP-SMX) (MIC50/90, ≤0.5/1 mg/liter; 95.4% susceptible) and minocycline (MIC50/90, 0.5/2 mg/liter; 99.5% susceptible) were also very active. Aztreonam-avibactam inhibited 84.7% of non-TMP-SMX-susceptible isolates at ≤8 mg/liter. Aztreonam-avibactam may represent a valuable option for the treatment of S. maltophilia infections, addressing a major unmet medical need.
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Esposito S, Stone GG, Papaparaskevas J. In vitro activity of aztreonam/avibactam against a global collection of Klebsiella pneumoniae collected from defined culture sources in 2016 and 2017. J Glob Antimicrob Resist 2020; 24:14-22. [PMID: 32841721 DOI: 10.1016/j.jgar.2020.08.004] [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] [Received: 04/30/2020] [Revised: 07/12/2020] [Accepted: 08/03/2020] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES This study reports on the activity of aztreonam/avibactam (ATM-AVI) against a collection of Klebsiella pneumoniae collected in 2016 and 2017. METHODS Non-duplicate K. pneumoniae isolates were collected from four regions (Africa/Middle East, n = 785; Asia-Pacific, n = 1433; Europe, n = 4236; Latin America, n = 1499) and five culture sources (blood, n = 902; intra-abdominal, n = 992; urinary tract, n = 2148; skin and skin structure, n = 1409; lower respiratory tract, n = 2502). MICs were determined at a central laboratory using Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodology. Susceptibility was determined using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. RESULTS For all culture sources, against all K. pneumoniae, the highest rates of susceptibility were seen for amikacin (>84%), ceftazidime/avibactam (>94%), colistin (>92%) and meropenem (>83%), and >99.9% of isolates were inhibited at an ATM-AVI MIC of ≤4 mg/L. Among meropenem-resistant (MEM-R, n = 583) and meropenem-resistant metallo-β-lactamase-negative (MEM-R-MBLN; n = 469) isolates, susceptibility was highest to ceftazidime/avibactam (79.9% and 99.4%, respectively) and colistin (67.2% and 62.7%, respectively). All MEM-R-MBLN isolates from blood, intra-abdominal, urinary tract and skin and skin structure sources, and all but one isolate from respiratory sources, were inhibited at an ATM-AVI MIC of ≤2 mg/L. Against the meropenem-resistant metallo-β-lactamase positive (MEM-R-MBLP; n = 114) isolates, susceptibility to colistin was between 75.0% (urinary tract isolates) and 93.3% (lower respiratory tract isolates). All MEM-R-MBLP isolates were inhibited at an ATM-AVI MIC of ≤0.5 mg/L. CONCLUSIONS ATM-AVI is active against K. pneumoniae isolates from a range of culture sources across Africa/Middle East, Asia-Pacific, Europe and Latin America. ATM-AVI also has activity against MEM-R-MBLN and MEM-R-MBLP isolates.
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Affiliation(s)
- S Esposito
- Department of Infectious Diseases, University of Salerno, Salerno, Italy
| | - G G Stone
- Pfizer Inc., 558 Eastern Point Rd, Groton, CT 06340, USA
| | - J Papaparaskevas
- Microbiology Department, Medical School, National and Kapodistrian University of Athens, Mikras Asias 75, 11527 Athens, Greece.
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In Vitro Activity of Ceftazidime-Avibactam against Isolates from Respiratory and Blood Specimens from Patients with Nosocomial Pneumonia, Including Ventilator-Associated Pneumonia, in a Phase 3 Clinical Trial. Antimicrob Agents Chemother 2020; 64:AAC.02356-19. [PMID: 32071051 DOI: 10.1128/aac.02356-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/12/2020] [Indexed: 12/12/2022] Open
Abstract
Nosocomial pneumonia (NP), including ventilator-associated pneumonia (VAP), is increasingly associated with multidrug-resistant Gram-negative pathogens. This study describes the in vitro activity of ceftazidime-avibactam, ceftazidime, and relevant comparator agents against bacterial pathogens isolated from patients with NP, including VAP, enrolled in a ceftazidime-avibactam phase 3 trial. Gram-positive pathogens were included if coisolated with a Gram-negative pathogen. In vitro susceptibility was determined at a central laboratory using Clinical and Laboratory Standards Institute broth microdilution methods. Of 817 randomized patients, 457 (55.9%) had ≥1 Gram-negative bacterial pathogen(s) isolated at baseline, and 149 (18.2%) had ≥1 Gram-positive pathogen(s) coisolated. The most common isolated pathogens were Klebsiella pneumoniae (18.8%), Pseudomonas aeruginosa (15.8%), and Staphylococcus aureus (11.5%). Ceftazidime-avibactam was highly active in vitro against 370 isolates of Enterobacteriaceae, with 98.6% susceptible (MIC90, 0.5 μg/ml) compared with 73.2% susceptible for ceftazidime (MIC90, >64 μg/ml). The percent susceptibility values for ceftazidime-avibactam and ceftazidime against 129 P. aeruginosa isolates were 88.4% and 72.9% (MIC90 values of 16 μg/ml and 64 μg/ml), respectively. Among ceftazidime-nonsusceptible Gram-negative isolates, ceftazidime-avibactam percent susceptibility values were 94.9% for 99 Enterobacteriaceae and 60.0% for 35 P. aeruginosa MIC90 values for linezolid and vancomycin (permitted per protocol for Gram-positive coverage) were within their respective MIC susceptibility breakpoints against the Gram-positive pathogens isolated. This analysis demonstrates that ceftazidime-avibactam was active in vitro against the majority of Enterobacteriaceae and P. aeruginosa isolates from patients with NP, including VAP, in a phase 3 trial. (This study has been registered at ClinicalTrials.gov under identifier NCT01808092.).
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12
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In Vitro Evaluation of Antifungal Drug Combinations against Multidrug-Resistant Candida auris Isolates from New York Outbreak. Antimicrob Agents Chemother 2020; 64:AAC.02195-19. [PMID: 31932367 DOI: 10.1128/aac.02195-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/04/2020] [Indexed: 01/29/2023] Open
Abstract
Since 2016, New York hospitals and health care facilities have faced an unprecedented outbreak of the pathogenic yeast Candida auris We tested over 1,000 C. auris isolates from affected facilities and found high resistance to fluconazole (MIC > 256 mg/liter) and variable resistance to other antifungal drugs. Therefore, we tested if two-drug combinations are effective in vitro against multidrug-resistant C. auris Broth microdilution antifungal combination plates were custom manufactured by TREK Diagnostic System. We used 100% inhibition endpoints for the drug combination as reported earlier for the intra- and interlaboratory agreements against Candida species. The results were derived from 12,960 readings, for 15 C. auris isolates tested against 864 two-drug antifungal combinations for nine antifungal drugs. Flucytosine (5FC) at 1.0 mg/liter potentiated the most combinations. For nine C. auris isolates resistant to amphotericin B (AMB; MIC ≥ 2.0 mg/liter), AMB-5FC (0.25/1.0 mg/liter) yielded 100% inhibition. Six C. auris isolates resistant to three echinocandins (anidulafungin [AFG], MIC ≥ 4.0 mg/liter; caspofungin [CAS], MIC ≥ 2.0 mg/liter; and micafungin [MFG], MIC ≥ 4.0 mg/liter) were 100% inhibited by AFG-5FC and CAS-5FC (0.0078/1 mg/liter) and MFG-5FC (0.12/1 mg/liter). None of the combinations were effective for C. auris 18-1 and 18-13 (fluconazole [FLC] > 256 mg/liter, 5FC > 32 mg/liter) except MFG-5FC (0.1/0.06 mg/liter). Thirteen isolates with a high voriconazole (VRC) MIC (>2 mg/liter) were 100% inhibited by the VRC-5FC (0.015/1 mg/liter). The simplified two-drug combination susceptibility test format would permit laboratories to provide clinicians and public health experts with additional data to manage multidrug-resistant C. auris.
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Dose Selection and Validation for Ceftazidime-Avibactam in Adults with Complicated Intra-abdominal Infections, Complicated Urinary Tract Infections, and Nosocomial Pneumonia. Antimicrob Agents Chemother 2019; 63:AAC.02187-18. [PMID: 30670413 DOI: 10.1128/aac.02187-18] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Avibactam is a non-β-lactam β-lactamase inhibitor that has been approved in combination with ceftazidime for the treatment of complicated intra-abdominal infections, complicated urinary tract infections, and nosocomial pneumonia, including ventilator-associated pneumonia. In Europe, ceftazidime-avibactam is also approved for the treatment of Gram-negative infections with limited treatment options. Selection and validation of the ceftazidime-avibactam dosage regimen was guided by an iterative process of population pharmacokinetic (PK) modelling, whereby population PK models for ceftazidime and avibactam were developed using PK data from clinical trials and updated periodically. These models were used in probability of target attainment (PTA) simulations using joint pharmacodynamic (PD) targets for ceftazidime and avibactam derived from preclinical data. Joint PTA was calculated based on the simultaneous achievement of the individual PK/PD targets (50% free time above the ceftazidime-avibactam MIC for ceftazidime and free time above a critical avibactam threshold concentration of 1 mg/liter for avibactam). The joint PTA analyses supported a ceftazidime-avibactam dosage regimen of 2,000 + 500 mg every 8 h by 2-h intravenous infusion for patients with creatinine clearance (CLCR) >50 ml/min across all approved indications and modified dosage regimens for patients with CLCR ≤50 ml/min. Subgroup simulations for individual phase 3 patients showed that the dosage regimen was robust, with high target attainment (>95%) against MICs ≤8 mg/liter achieved regardless of older age, obesity, augmented renal clearance, or severity of infection. This review summarizes how the approved ceftazidime-avibactam dosage regimens were developed and validated using PK/PD targets, population PK modeling, and PTA analyses.
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Ceftazidime-Avibactam Susceptibility Breakpoints against Enterobacteriaceae and Pseudomonas aeruginosa. Antimicrob Agents Chemother 2018; 62:AAC.02590-17. [PMID: 30061279 DOI: 10.1128/aac.02590-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 07/16/2018] [Indexed: 12/20/2022] Open
Abstract
Clinical susceptibility breakpoints against Enterobacteriaceae and Pseudomonas aeruginosa for the ceftazidime-avibactam dosage regimen of 2,000/500 mg every 8 h (q8h) by 2-h intravenous infusion (adjusted for renal function) have been established by the FDA, CLSI, and EUCAST as susceptible (MIC, ≤8 mg/liter) and resistant (MIC, >8 mg/liter). The key supportive data from pharmacokinetic/pharmacodynamic analyses, in vitro surveillance, including molecular understanding of relevant resistance mechanisms, and efficacy in regulatory clinical trials are collated and analyzed here.
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