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Sy SKB, Zhuang L, Xia H, Beaudoin ME, Schuck VJ, Nichols WW, Derendorf H. A mathematical model-based analysis of the time-kill kinetics of ceftazidime/avibactam against Pseudomonas aeruginosa. J Antimicrob Chemother 2019; 73:1295-1304. [PMID: 29415212 DOI: 10.1093/jac/dkx537] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 12/19/2017] [Indexed: 01/28/2023] Open
Abstract
Objectives To characterize quantitatively the effect of avibactam in potentiating ceftazidime against MDR Pseudomonas aeruginosa by developing a mathematical model to describe the bacterial response to constant concentration time-kill information and validating it using both constant and time-varying concentration-effect data from in vitro and in vivo infection systems. Methods The time course of the bacterial population dynamics in the presence of static concentrations of ceftazidime and avibactam was modelled using a two-state pharmacokinetic/pharmacodynamic (PK/PD) model, consisting of active and resting states, to account for bactericidal activities, bacteria-mediated ceftazidime degradation and inhibition of degradation by avibactam. Ceftazidime's effect on the bacterial population was described as an enhancement of the death rate of the active population, with the effect of avibactam being to increase ceftazidime potency. Model validation was performed by comparing simulated time courses of bacterial responses with those from in vitro and in vivo experimental exposures of ceftazidime and avibactam that represented those predicted in an average patient dosed with 2 g/0.5 g ceftazidime/avibactam administered every 8 h as 2 h infusions. Results The two-state model successfully described the bacterial population dynamics, ceftazidime degradation and its inhibition by avibactam. For external validation, the model correctly predicted the bacterial response of P. aeruginosa isolates evaluated in in vitro hollow-fibre and in vivo neutropenic mouse thigh and lung infection models. Conclusions The PK/PD model and modelled strains successfully replicated the spread in activity when compared with a large selection of P. aeruginosa strains reported in the literature.
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Affiliation(s)
- Sherwin K B Sy
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Luning Zhuang
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Huiming Xia
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | | | | | | | - Hartmut Derendorf
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
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Sy SKB, Zhuang L, Xia H, Schuck VJ, Nichols WW, Derendorf H. A model-based analysis of pharmacokinetic-pharmacodynamic (PK/PD) indices of avibactam against Pseudomonas aeruginosa. Clin Microbiol Infect 2018; 25:904.e9-904.e16. [PMID: 30394361 DOI: 10.1016/j.cmi.2018.10.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 10/11/2018] [Accepted: 10/17/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The aim of the present work was to use a semi-mechanistic pharmacokinetic-pharmacodynamic (PK/PD) model developed from in vitro time-kill measurements with P. aeruginosa to compare different pharmacodynamic indices derived from simulated human avibactam exposures, with respect to their degree of correlation with the modelled bacterial responses. METHODS A mathematical model of the effect of ceftazidime-avibactam on the growth dynamics of P. aeruginosa was used to simulate bacterial responses to modelled human exposures from fractionated avibactam dosing regimens with a fixed ceftazidime dosing regimen (2 or 8 g q8h as a 2-h infusion). The relatedness of the 24-h change in bacterial density and avibactam exposure parameters was evaluated to determine exposure parameter that closely correlated with bacterial growth/killing responses. RESULTS Frequent dosing was associated with higher efficacy, resulting in a reduction of avibactam daily dose. The best-fit PD index of avibactam determined from the simulation was fT > CT of 1 mg/L avibactam and q8h was the longest dosing interval able to achieve 2-log kill: 41-87% (3.3 h to 7.0 h out of 8-h interval, respectively). The avibactam exposure magnitude required to achieve a 2-log kill in the simulations was dependent on the susceptibility of the bacterial isolate to ceftazidime. CONCLUSIONS Avibactam activity in combination with ceftazidime against multidrug resistant P. aeruginosa correlated with fT > CT. Setting a threshold avibactam concentration to 1 mg/L, superimposed over a simulated human-like exposure of ceftazidime, achieved at least 2-log kill for the clinical dose of 500 mg q8h avibactam as a 2-h infusion, depending on the minimum inhibitory concentration of ceftazidime alone.
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Affiliation(s)
- S K B Sy
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - L Zhuang
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - H Xia
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | | | | | - H Derendorf
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA.
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Sy SKB, Zhuang L, Beaudoin ME, Kircher P, Tabosa MAM, Cavalcanti NCT, Grunwitz C, Pieper S, Schuck VJ, Nichols WW, Derendorf H. Potentiation of ceftazidime by avibactam against β-lactam-resistant Pseudomonas aeruginosa in an in vitro infection model. J Antimicrob Chemother 2017; 72:1109-1117. [PMID: 28077672 DOI: 10.1093/jac/dkw535] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 11/11/2016] [Indexed: 12/15/2022] Open
Abstract
Objectives This study evaluated the in vitro pharmacodynamics of combinations of ceftazidime and the non-β-lactam β-lactamase inhibitor, avibactam, against ceftazidime-, piperacillin/tazobactam- and meropenem-multiresistant Pseudomonas aeruginosa by a quantitative time-kill method. Methods MICs of ceftazidime plus 0-16 mg/L avibactam were determined against eight isolates of P. aeruginosa . Single-compartment, 24 h time-kill kinetics were investigated for three isolates at 0-16 mg/L avibactam with ceftazidime at 0.25-4-fold the MIC as measured at the respective avibactam concentration. Ceftazidime and avibactam concentrations were measured by LC-MS/MS during the time-kill kinetic studies to evaluate drug degradation. Results Avibactam alone displayed no antimicrobial activity. MICs of ceftazidime decreased by 8-16-fold in the presence of avibactam at 4 mg/L. The changes in log 10 cfu/mL at both the 10 h and 24 h timepoints (versus 0 h) revealed bacterial killing at ≥1-fold MIC. Significantly higher concentrations of ceftazidime alone, as compared with those of ceftazidime in combination, were required to produce any given kill. Without avibactam, ceftazidime degradation was significant (defined as degradation t 1/2 < 24 h), with as little as 19% ± 18% of the original concentration remaining at 8 h for the most resistant strain. In combination with avibactam, ceftazidime degradation at ≥ 1-fold MIC was negligible. Conclusion The addition of avibactam protected ceftazidime from degradation in a dose-dependent manner and restored its cidal and static activity at concentrations in combination well below the MIC of ceftazidime alone.
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Affiliation(s)
- Sherwin K B Sy
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Luning Zhuang
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | | | - Philipp Kircher
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Maria A M Tabosa
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Noely C T Cavalcanti
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Christian Grunwitz
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Sebastian Pieper
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | | | | | - Hartmut Derendorf
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA
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Sy SKB, Zhuang L, Xia H, Beaudoin M, Schuck VJ, Derendorf H. Prediction of in vivo and in vitro infection model results using a semimechanistic model of avibactam and aztreonam combination against multidrug resistant organisms. CPT Pharmacometrics Syst Pharmacol 2017; 6:197-207. [PMID: 28145085 PMCID: PMC5351411 DOI: 10.1002/psp4.12159] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 11/01/2016] [Accepted: 11/11/2016] [Indexed: 01/05/2023]
Abstract
The combination of aztreonam‐avibactam is active against multidrug‐resistant Enterobacteriaceae that express metallo‐β‐lactamases. A complex synergistic interaction exists between aztreonam and avibactam bactericidal activities that have not been quantitatively explored. A two‐state semimechanistic pharmacokinetic/pharmacodynamic (PK/PD) logistic growth model was developed to account for antimicrobial activities in the combination of bacteria‐mediated degradation of aztreonam and the inhibition of aztreonam degradation by avibactam. The model predicted that changing regimens of 2 g aztreonam plus 0.375 and 0.6 g avibactam as a 1‐hour infusion were qualitatively similar to that observed from in vivo murine thigh infection and hollow‐fiber infection models previously reported in the literature with 24‐hour log kill ≥1. The current approach to characterize the effect of avibactam in enhancing aztreonam activity from time‐kill study was accomplished by shifting the half‐maximal effective concentration (EC50) of aztreonam in increasing avibactam concentration using a nonlinear equation as a function of avibactam concentration, providing a framework for translational predictions.
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Affiliation(s)
- SKB Sy
- Department of Pharmaceutics, College of PharmacyUniversity of FloridaGainesvilleFloridaUSA
| | - L Zhuang
- Department of Pharmaceutics, College of PharmacyUniversity of FloridaGainesvilleFloridaUSA
| | - H Xia
- Department of Molecular Genetics and Microbiology, College of MedicineUniversity of FloridaGainesvilleFloridaUSA
| | | | | | - H Derendorf
- Department of Pharmaceutics, College of PharmacyUniversity of FloridaGainesvilleFloridaUSA
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Sy SKB, Beaudoin ME, Zhuang L, Löblein KI, Lux C, Kissel M, Tremmel R, Frank C, Strasser S, Heuberger JAAC, Mulder MB, Schuck VJ, Derendorf H. In vitropharmacokinetics/pharmacodynamics of the combination of avibactam and aztreonam against MDR organisms. J Antimicrob Chemother 2016; 71:1866-80. [DOI: 10.1093/jac/dkw082] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 02/21/2016] [Indexed: 11/12/2022] Open
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Berkhout J, Melchers MJ, van Mil AC, Seyedmousavi S, Lagarde CM, Schuck VJ, Nichols WW, Mouton JW. Pharmacodynamics of Ceftazidime and Avibactam in Neutropenic Mice with Thigh or Lung Infection. Antimicrob Agents Chemother 2016; 60:368-75. [PMID: 26525790 PMCID: PMC4704241 DOI: 10.1128/aac.01269-15] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/22/2015] [Indexed: 11/20/2022] Open
Abstract
Avibactam is a new non-β-lactam β-lactamase inhibitor that shows promising restoration of ceftazidime activity against microorganisms producing Ambler class A extended-spectrum β-lactamases (ESBLs) and carbapenemases such as KPCs, class C β-lactamases (AmpC), and some class D enzymes. To determine optimal dosing combinations of ceftazidime-avibactam for treating infections with ceftazidime-resistant Pseudomonas aeruginosa, pharmacodynamic responses were explored in murine neutropenic thigh and lung infection models. Exposure-response relationships for ceftazidime monotherapy were determined first. Subsequently, the efficacy of adding avibactam every 2 h (q2h) or q8h to a fixed q2h dose of ceftazidime was determined in lung infection for two strains. Dosing avibactam q2h was significantly more efficacious, reducing the avibactam daily dose for static effect by factors of 2.7 and 10.1, whereas the mean percentage of the dosing interval that free drug concentrations remain above the threshold concentration of 1 mg/liter (%fT>C(T) 1 mg/liter) yielding bacteriostasis was similar for both regimens, with mean values of 21.6 (q2h) and 18.5 (q8h). Dose fractionation studies of avibactam in both the thigh and lung models indicated that the effect of avibactam correlated well with %fT>C(T) 1 mg/liter. This parameter of avibactam was further explored for four P. aeruginosa strains in the lung model and six in the thigh model. Parameter estimates of %fT>C(T) 1 mg/liter for avibactam ranged from 0 to 21.4% in the lung model and from 14.1 to 62.5% in the thigh model to achieve stasis. In conclusion, addition of avibactam enhanced the effect of ceftazidime, which was more pronounced at frequent dosing and well related with %fT>C(T) 1 mg/liter. The thigh model appeared more stringent, with higher values, ranging up to 62.5% fT>C(T) 1 mg/liter, required for a static effect.
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Affiliation(s)
- Johanna Berkhout
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands
| | - Maria J Melchers
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Anita C van Mil
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands
| | | | - Claudia M Lagarde
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Virna J Schuck
- AstraZeneca Pharmaceuticals, Waltham, Massachusetts, USA
| | | | - Johan W Mouton
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
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